Giant Rodents of South America Roedores gigantes de América del Sur カピバラの巨大な祖先水豚巨祖先

The largest rodent discovered so far is the massive Josephoartigasia Monesi, who was about the size of a bull buffalo (and much bigger than a 2-year-old Hereford bull – a Hereford bull only weighs about 700 kg!) and weighed about 1000 kg, with a very powerful bite force. Isostylomys laurillardi is thought to have been nearly as large.  Arazamys castiglionii weighed about 800 – 900 kg, smaller than Josephoartigasia Monesi and Isostylomys, but larger than Phoberomys; they were almost the size of a buffalo.

For reference: Pleistocene: 2.58 million years ago – 11,700 years ago, ended with the Ice Age. Pliocene: 5.333 million years ago – 2.58 million years ago. Miocene: 23.03 million years ago – 5.333 million years ago. Oligocene: 33.9 million years ago – 23.03 million years ago. Tertiary: 65 million years ago – 2.588 million years ago. Quaternary 2.6 million years ago into the present.

Phoberomys compared to human size and capybara

Size comparison between human, capybara and the genus Phoberomys. Phoberomys only weighed about 700 kg. Josephoartigasia Monesi was much larger and weighed 1000 kg

This is an overview of some of the many species of giant rodent who roamed South America during the Miocene, Pliocene and Pleistocene epochs, which lasted from 23 million years ago until the start of the last Ice Age, 11,700 years ago. Most of these giant rodents lived between 9 – 2 million years ago.

Palaeontologists believe there may have been over 50 species of giant rodent, but when the fossil evidence consists of only one or two fragments of mandible or skull (the bone most likely to survive over millions of years), or a tooth, it can be challenging to identify a species! Teeth survive for thousands, even millions, of years because of the strength of the enamel covering the teeth which is 97% mineral making teeth stronger than bones. Teeth and fragments of skull or mandible, are often the only fossil evidence that palaeontologists have when trying to identify different species of these long extinct giant rodents. Thus the different morphology and size of the teeth, and differing features of fragmentary pieces of skull or mandible, are crucial clues when identifying long extinct species.

Rodents appear in the fossil record in South America at least 31.5 million years ago, during the very early Oligocene.  The earliest caviomorph fossils have been found in Peru and dated to the late Oligocene. Capybaras are caviomorph rodents; the Caviomorpha clade is a subgroup of hystricognath (see paragraph below) rodents. South America was separated from other landmasses during most of the Tertiary, so evidence is lacking as to how rodents reached South America. Hystricognaths originated in Asia, but the South American rodents probably arrived from Africa by raft. The ancestors of most of today’s South American rodents, including capybaras, probably appeared between the middle and late Miocene. These giant rodent lineages in South America went extinct over 1 million years ago, some millions of years ago, with only the capybara alive today as the largest extant rodent. Hydrochoerus hydrochaeris, the most numerous and well-known of the two species of modern-day capybara, weighs on average about 50 to 60 kg, and is about the size of a large dog.

The Hystricognath rodents are an Infraorder of rodents distinguished from other rodents by the bone structure of their skulls. There are 18 families within the Hystricognathi, divided into 2 Parvorders, the Caviomorpha and the Phiomorpha. Capybaras are representatives of the Family Caviidae in the Parvorder Caviomorpha. Caviomorpha are mostly found in South America, with a few species in North America and the Caribbean. The Phiomorpha are found in the Old World.

A Clade is a group believed to include all the evolutionary descendants of a common ancestor.

Rodents are the most abundant group of living mammals. They also vary enormously in size. The smallest, about the size of a pygmy mouse, weighs only a few grams, while the largest, the extinct giant rodent Josephoartigasia Monesi weighed about 1000 kg. Rodents are also one of the most diverse mammals in South America, with over 160 species in total, either living today or extinct species. Today’s rodents include arboreal (tree dwellers), gliding rodents, fossorial (adapted to digging and living primarily but not exclusively underground), cursorial (adapted specifically to run; i.e. can run fast or maintain a constant speed over a long distance) and semi aquatic rodents. During the Tertiary rodents’ range of body size and physical characteristics was wider than today.

Some scientists have suggested these giant rodents may have gone extinct because they were not fast enough to outrun predators, and too large to dig burrows to hide in. Climate change may also have contributed to their demise.

Other extinct giant rodents include: the genus Eumegamys who weighed about 800 – 900 kg, and was a similar size to a hippopotamus. Phoberomys burmeisteri, believed to be the largest of this genus. Phoberomys Pattersoni thought to have weighed about 700 kg, and Phoberomys insolita (although Phoberomys insolita may have been a sub adult Phoberomys pattersoni) thought to have weighed about 400 kg. These predate Josephoartigasia Monesi and lived during the late Miocene in modern day Venezuela. Telicomys gigantissimus, the size of a small rhinoceros, about 2 meters long and with a weight of about 500 kg. and about 70% of the size of Phoberomys pattersoni.  Neoepiblema Acreensis, weighed about 80 kg. (See below for more about these giant rodents)

J Monesi to

Artist’s impression of Josephoartigasia Monesi, who was the size of a massive bull buffalo and weighed about 1000 kg

In 1987, the almost complete skull of Josephoartigasia Monesi was discovered in modern day Uruguay on the coast of the Rio De La Plata, in the San José formation. Based on the strata of the San José formation in which the J Monesi fossil was found, J Monesi lived 4 – 2 million years ago, during the Pliocene and early Pleistocene.

J Monesi is believed to have lived in a lowland forested, wetland habitat such as a delta or estuary. By identifying the diet of an extinct species (see below) scientists are able to speculate on the type of habitat the species lived in based on the vegetation it foraged. J Monesi shared its habitat with giant ground sloths, and predators such as enormous flightless “terror birds” sparassodonts, short faced bears and sabre toothed tigers.

Another feature of J Monesi that is especially interesting are its teeth. J Monesi had enormous, incredibly powerful, chisel -shaped incisors, an adaptation which allowed these incisors to be successfully used in hierarchy battles between males to ensure access to females and breeding rights, and in defence against predators. J Monesi may also have used their enormous incisors for digging in the same way that an elephant uses its tusks. These incisors were able to resist much greater forces than the molars, powered by the masticatory muscles, could generate. The molars are believed to have been used to masticate tough vegetation with forceful bites. Josephoartigasia Monesi’s diet probably consisted of grasses, aquatic plants and the bark of trees and bushes. As large mammals they would have been able to utilise these coarse, low quality food resources which much smaller species would not have been able to digest.

Representatives of the Dinomyidae family frequently had incisors which were able to resist much greater forces than their molars.

Scientific Classification: Josephoartigasia Monesi    Kingdom: Animalia Phylum: Chordata Class Mammalia Order: Rodentia Suborder: Hystricomorpha Infraorder: Hystricognath Family: Dinomyidae Genus: Josephoartigasia Species: Josephoartigasia Monesi

It can be challenging to make an accurate identification of different extinct rodent species as palaeontologists are often working from scant fossil remains, consisting of only a few fragments of mandible or skull (the bone most likely to survive) or a tooth. Some fossils which were thought to represent different species have been reassessed as representing juveniles, sub adults and adults of the same species. Some of these mega rodents had a unique, and complicated tooth morphology which changed as they aged (as is the case with capybaras). This change accounts for some of the erroneous designations of fossils, which were initially thought to represent different species’, but are now considered to be representatives of the same species, but of different ages. With other species the size of the teeth did not grow or change as the animal developed from being a juvenile to an adult. This means that the juvenile and the adult had the same sized teeth and were not different species.

Likewise, it can be difficult to gauge the size of the animal, and make size comparisons between different extinct species, unless the identical parts of the respective bodies are found. For example, the body size for Phoberomys pattersoni is based on parts of the fore limb and hind limb, and these were compared with this species closest living relative, the Pacarana. In the case of Josephoartigasia Monesi an almost complete skull was found. Although J Monesi is known only from this 1.7 foot (just over half a meter) long skull, this provided enough fossil evidence to indicate that this was a new species and the largest rodent who ever lived. To arrive at a body mass for J Monesi this skull was compared with several other living rodent species.

There are two methods scientists use to identify the diet of prehistoric species. Where fossil evidence is available scientists can investigate the preserved contents of the gut and faeces, both inside the body (cololites) and outside the body (coprolites). Scientists also study the chemical isotope in the fossil bones and teeth of these long extinct species, and compare this information with the carbon isotopes of different varieties of plants, to identify the animal’s diet. The isotopic signature of the food eaten by the animal is incorporated into the fossil bones and teeth, and remain stable over tens of thousands, even millions, of years. Teeth are often the only fossil remains of an extinct species which palaeontologists find, as teeth, being harder due to their enamel cover, survive better than bones. Palaeontologists also used the condition of Josephoartigasia Monesi’s teeth, the degree of wear and worn edges, pits and scratches, to assess the type of diet this species relied on.

The almost complete skull of J Monesi provided new information about the anatomy of extinct giant rodents of the Dinomyidae family who are primarily known from scant fossil evidence. The mandible is the largest and strongest facial bone, and forms the lower jaw, acting as a receptacle for the lower teeth. Together with the temporal bone, the mandible articulates on either side forming the temporomandibular joint. Scientists compared the mandible of J Monesi to that of its closest living relative, the Pacarana, to help them rebuild J Monesi skull. To simulate how J Monesi would bite at different locations along the jaw, scientists used a 3-D scan of this Pacarana mandible. J Monesi had an extremely powerful bite, estimated to be 3 times more powerful than a tiger’s bite, and comparable to modern day large crocodilians. The maximum bite force of its incisors has been estimated at close to 500 kg. The molars could only exert a maximum force of about 150 kg (about 300 lbs); thus the incisors were able to exert a much more powerful force.  J Monesi’s incisors were extremely strong and could resist greater forces than the masticatory muscles of the molars could generate, leading scientists to speculate that the primary role of these incisors was use in hierarchical combat, or defence against predators. The molars were primarily used to chew tough vegetation.

Palaeontologists are also able to estimate the bite force and how the stress of chewing might have affected the skull, by using an engineering technique, Finite Element Analysis. The maximum bite force of Josephoartigasia Monesi has been estimated at a maximum of 4165N, which is 3 times as powerful as a tiger.

Josephoartigasia Monesi’s closest living relative is the Pacarana, a critically endangered species at high risk of extinction, and the last surviving member of “their” family, the Dinomyidae. The Pacarana, Dinomys branickii, is a rare hystricognath rodent found only in small areas in South America. They are the second largest rodent species alive today; second only to the capybara, with a body length of about 80 cm (31 inches) and weighing about 15 kg (32 lbs). Pacaranas have a large head and a thick, furry tail. The name comes from the Tupi word meaning “false paca”, named because they look superficially similar to the paca. Due to the Pacarana’s low population levels, scientists had believed the animals were extinct. Like many species around the world today, they are vulnerable to human predation and habitat loss caused by human activities.

The Dinomyidae are a family of hystricognath rodents native to South America. Several extinct members of this family include the largest rodents who have ever lived, including the largest so far discovered, Josephoartigasia Monesi. The Dinomyidae are believed to have been large grazing mammals, the largest representatives of this family disappeared after the formation of the Isthmus of Panama about 3 million years ago, connecting North and South America. There were once many species in this group but now only the Pacarana survives.

The earliest fossils of the Dinomyidae family date from the middle Miocene, and fossils of this family have been found almost throughout South America. The clade reached its highest diversity (i.e. the greatest number of species of this family) in the late Miocene. The family is subdivided into 4 or 5 subfamilies: Potamarchinae (which includes the oldest known representatives of the family, possibly from the middle Miocene to the early Pleistocene). Gyriabrinae (late Miocene to late Pliocene). Dinomyinae (including the only living representative, Dinomyinae branickii – Pacarana). Eumegamyinae (late Miocene to the late Pliocene, and includes some of the largest members of the family). Tetrastylinae (late Miocene to late Pliocene. May be a subgroup of Eumegamyinae or Dinomyinae). It is not possible to determine the anatomy of these animals as there is insufficient fossil evidence: just a few fragments of mandible or skull, or a tooth.

Isostylomys laurillardi.

Artist’s impression of Isostylomys laurillardi, who was almost as large as Josephoartigasia Monesi

Isostylomys laurdillardi, is one of the largest species of giant rodent who lived during the Miocene epoch, 9 – 6.8 million years ago. This species is believed to have weighed almost 1000 kg.

In 2016 scientists found an almost complete and intact skull and part of the jaw of one adult, and the complete lower jaw, with all its teeth intact, and the right heel of a juvenile, of this species. The fossils were found in southern Uruguay in the Camacho Formation of the Rio de la Plata coastal region. Uruguay’s Camacho Formation was laid down during the late Miocene epoch, 12 million years ago – 5 million years ago.

The fossils were in exceptional condition, the best preserved fossils found so far for this species; previous finds amounted to only fragments of skull and the odd tooth. This allowed the scientists to compare tooth development between the adult and juvenile of this species. This led to a new understanding of the other species in this genus, which had previously only been studied from fragmentary fossil evidence.

These fossils, which represent an adult and juvenile, raise questions regarding the classification within their genus, Isostylomys, suggesting that fossils thought to indicate different, related species may in fact represent a single species, due to the way teeth are formed as the rodent ages.

The scientists discovered that the adult tooth shape emerged quite early in the rodent’s development, growing larger as the animal matured. By evaluating earlier fossils, considered to be the tooth forms for prenatal, juvenile and adult, they learned that adult tooth forms could vary in size. This led to an understanding that fossils which had been thought to represent related species, three species of Isostylomys, were in fact just one species of Isostylomys, representing different age groups, rather than different species.

As a result of this analysis, which showed that from a very young age the giant rodents were very similar to the adults, scientists have been able to learn how the world’s largest fossil rodents grow.

Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Rodentia
Suborder: Hystricomorpha
Infraorder: Hystricognathi
Superfamily: Chinchilloidea
Family: †Dinomyidae
Genus: †Isostylomys
Species:Isostylomys laurillardi

Arazamys castiglionii weighed about 800 – 900 kg, smaller than Josephoartigasia Monesi and Isostylomys, but larger than Phoberomys. They were almost the size of a buffalo. This species lived in the late Miocene. An incomplete skull of an adult was found in the Camacho Formation, in the San Jose Department, Uruguay. As with many other members of the Dinomyidae family, the molars are small relative to the large, powerful incisors and the estimated size of the skull.


Artist’s impression of Phoberomys pattersonii

Phoberomys pattersoni was a giant caviomorph rodent who lived during the late Miocene from about 9.0 – 6.8 million years ago. They lived in South America, in modern day Brazil, Argentina, Venezuela and Peru. Sedimentary evidence indicates they lived in coastal wetland habitats consisting of lagoons of shallow water separated from the coast by barriers of sand.

An almost complete fossil skeleton of Phoberomys pattersoni was discovered in 2000, in the Urumaco formation of the Orinoco River delta in Venezuela. The skeleton measured 3 meters (9.8 feet) with a 1.5 meter long tail (4.9 feet). This species was estimated to have weighed about 700 kg (1540 lbs). These size and weight estimates are reasonably accurate as almost an entire skeleton was discovered.

In appearance they may have looked more like a guinea pig than a rat. However, the humerus (which is part of the forelimb) gave a smaller estimate of body size than the femur (which is part of the hind limb), 436 kg as against 741 kg. This suggests that the hind limbs played a more important role in locomotion and weight support. The forelimbs may have been used to manipulate food as is the case with the Pacarama (Dinomyidae branickii) the only living member of this family.

The genus Phoberomys were herbivores, and like many rodent species they had high crowned premolars and molars indicating they were grazing animals i.e. grass eaters. The morphology of its teeth indicates that its diet was abrasive: coarse grasses and probably included aquatic grasses. Like the capybara, Phoberomys are believed to have been semi aquatic. Like Josephoartigasia Monesi, Phoberomys is a member of the family Diomyidae, whose only living relative, the Pacarana, is in danger of extinction.

Predators would have included large, very powerful birds like Brontornis and Kelenken, giant crocodilians. Sabre toothed marsupials would have preyed on the young.

As mentioned previously, reclassification sometimes occurs following further research, due to the challenges of identifying a species based on scant fossil remains, possibly only a few bones or teeth.

As an indication of this: the genus Phoberomys was thought, at one time, to consist of seven species, including: Phoberomys burmeisteri, Phoberomys praecursor, Phoberomys insolita, Phoberomys lozanoi and Phoberomys minima. However, a more recent study of Phoberomys fossils found in the Entre Rios province in Argentina, and dated to the late Miocene epoch, concluded that these were in fact just one species: Phoberomys burmeisteri. The study concluded that the differences among the fossils reflect different ages and stages of development of a single species. This gives an idea of just how difficult it is to accurately identify species from a very sparse fossil record.

Recent research also suggests that Phoberomys pattersoni and Phoberomys insolita may in fact be the same species. Phoberomys insolita had been estimated to be a little larger.

Scientific Classification Phoberomys pattersoni:    Kingdom: Animalia   Phylum: Chordata   Class: Mammalia   Order: Rodentia   Suborder: Histricomorpha   Family: Dinomyidae;   Genus: Phoberomys   Species: Phoberomys pattersoni

Phoberomys burmeisteri is believed to be the largest member of the Phoberomys genus who lived in the late Miocene epoch. The remains of this species was found in the Ituzaingó formation in Entre Rios province in Argentina.

Eumegamys is an extinct genus of giant rodent, about the size of a hippopotamus, of the family Dinomyidae. They lived during the late Miocene and Pliocene. Their fossil remains have been found in the Solimoes Formation in modern day Brazil, the Urumaco Formation in Venezuela, and the Ituzaingó formation in Argentina. It’s skull was about half a meter long (1.65 ft).

Telicomys gigantissimus lived in South America during the late Miocene and early Pliocene epochs (11.2 million – 5.3 million years ago). They were about the size of a small rhinoceros, about 2 meters long, and are thought to have weighed about 500 kg. They also were a member of the family Dinomyidae related to the Pacarana.

Eumegamys paranensis is an extinct species of giant rodent of the family Dinomyidae, who lived during the late Miocene and Pliocene in modern day Brazil, Venezuela and Argentina. It’s skull was 50 cm long. Evaluation of its cheek teeth, and the complexity of the crown, indicate that its diet consisted of coarse vegetation and demanding food items, and it was able to process more food each time it chewed (i.e. each masticatory cycle). Eumegamys paranensis fed on a varied diet, foraging close to the ground. It was probably a wide-ranging species, living near water and in gallery forests (narrow bands of forested area lining rivers) as would have been found in the Mesopotamic area of what is now the Paraná River system in north-east Argentina. This genus also lived in Brazil and Argentina.

Neoepiblema Acreensis is an extinct giant rodent, a relative of chinchillas, who weighed about 80 kg and lived about 10 million years ago in present-day Brazil in South America.

Using computerised tomography to look inside fossil skulls, scientists estimate that the brain of Neoepiblema Acreensis weighed just 47 g, meaning this rodent’s brain was unusually small compared to its body size. Two Neoepiblema Acreensis fossil skulls were studied, which gave an encephalisation quotient of 0.20 for one and 0.33 for the other. South American rodents alive today have an average encephalisation quotient above 1.05.

To compare the brain sizes of different animals of varying weights, scientists calculate a species’ “encephalisation quotient”, which measures the difference between the expected brain size based on body size, and the actual brain size for an animal of a given weight. Any value under 1 means that an animal’s brain is smaller than expected. The ratio between the size of the brain and the size of the body is thought to indicate intellectual ability.

This has led scientists to speculate that Neoepiblema Acreensis was not the brightest rodent. If this was indeed the case, the reason may have been that there were few predators to outwit so a larger brain was not worth the “cost” of maintaining a larger brain.

Critical Care for Capybaras. Capybara Health Care. This Could Save the Life of Your Capybara.

See below for the milk formula for baby capybaras. It is of course very important that any baby capybara who is not suckling (i.e. drinking his mother’s milk) is given the right formula of milk in order for the baby to thrive.

Please also see my blog about capybara diet. Many pet capybaras die prematurely because they are not given the right diet:

What Should I Feed My Pet Capybara?:

If you have a capybara who is not eating properly, or becoming very thin, this nutritional formula made by Oxbow, Critical Care for Herbivores, is recommended by a vet who specialises in treating capybaras. Your capybara may have tooth problems (which will need to be attended to) which makes chewing painful, or he might have an illness, or be recovering from surgery. This product has everything a capybara needs for optimum nutrition and health and recovery.

Remember that if your capybara has not been eating very much, his stomach will have shrunk. This means he will only be able to eat small quantities of food at any one time. You will need to keep offering him this formula, in small quantities, throughout the day to ensure he gets adequate nutrition.

As capybaras age, like humans, they may lose their appetites, or start to eat less. This will result in their stomach shrinking and they may only be able to eat a smaller amount of food at any one time; but they should be encouraged to eat more frequently to offset this. (This will not be necessary if the capybara has access to unlimited grazing or pellets 24/7 and continues to eat sufficient grass and pellets). This Critical Care formula is a good way to boost a capybara’s nutritional requirement.

Critical Care for Herbivores is a high protein, high energy, high fibre, easily digested powdered formula, with all the essential vitamins and minerals.

It is designed to be palatable so that your capybara enjoys it and wants to eat. It contains high-fibre Timothy hay to support proper gut physiology and digestion. It comes as a powder.

One friend found that his capybara did not like this formula when it was mixed with water, but he loved it when it was mixed with unsweetened almond milk. His capybara had already established a love of drinking unsweetened almond milk.

If your capybara is bonded with the human that human MUST give a capybara lots and lots of love and petting. You will need to spend much more time with him than you normally would otherwise we might lose the will to live, give up and die. Petting releases the hormone, oxytocin, and induces relaxation and plays a significant role in the bonding process. Your capybara will be very anxious during this time when he is suffering, and petting will help him relax. I cannot stress too strongly the importance of “being there” for your capybara at this critical time. Your love and time spent with the capybara could be the difference between life and death.

A Critical Care Formula in the form of a crunchy “biscuit”, is also available, and chewing it will be good for your capybara’s teeth.


“Developed with the assistance of top exotics veterinarians and nutritionists, Critical Care is the industry standard in recovery nutrition for herbivores with poor nutritional status resulting from illness or surgery.  Critical Care contains all the essential nutrients of a complete diet, as well as high-fiber timothy hay to support proper gut physiology and digestion.”

Critical Care for Herbivores, contains the following:

Timothy Grass Meal, Soybean Hulls, Soybean Meal, Wheat Germ, Xanthan Gum, Potassium Chloride, Salt, L-Ascorbyl-2-Polyphosphate (Vitamin C), Soybean Oil, Flaxseed, Magnesium Sulfate, Calcium Chloride, Papaya, Pineapple, Cane Molasses, Natural Apple Flavor, Natural Banana Flavor, DL-Methionine, L-Glutamine, Oat Groats, Wheat Middlings, Sodium Bentonite, Yeast Culture (dehydrated), Fat Product, Hydrolyzed Yeast, Inulin, Mixed Tocopherols (preservative), Choline Chloride, Vitamin E Supplement, Zinc Sulfate, Zine Proteinate, Niacin, Copper Sulfate, d-Calcium Pantothenate, Vitamin A Supplement, Manganous Oxide, Riboflavin Supplement, Biotin, Thiamine Mononitrate, Copper Proteinate, Sodium Selenite, Manganese Proteinate, Pyridoxine Hydrochloride, Folic Acid, Vitamin D3 Supplement, Cobalt Carbonate, Vitamin B12 Supplement, Calcium Iodate, Rosemary Extract

Guaranteed Analysis

  • Crude Protein (min) 17.00%
  • Crude Fat (min) 5.00%
  • Crude Fiber (min) 21.00%
  • Crude Fiber (max) 26.00%
  • Moisture (max) 10.00%
  • Ash (max) 10.00%
  • Calcium (min) 0.60%
  • Calcium (max) 0.80%
  • Phosphorus (min) 0.40%
  • Vitamin A (min) 10,000 IU/kg
  • Vitamin D3 (min) 900 IU/kg
  • Vitamin E (min) 190 IU/kg
  • Ascorbic Acid (Vitamin C) (min) 1,500 mg/kg

Calorie Content

  • Metabolizable Energy (calculated) 2,660 kcal/kg or 24 kcal/Tbsp

“Product Highlights:

  • Powdered formula mixes easily to desired consistency
  • Highly versatile – can be tube fed, assist-fed by syringe or spoon, or self-fed by bowl or as top dressing
  • High in fiber; low in carbohydrates
  • Contains readily-absorbable chelated minerals and beneficial prebiotics
  • No refined sugars, artificial preservatives or simple carbohydrates
  • High digestibility and palatability
  • Contains stabilized form of Vitamin C

Available in Anise and Apple-Banana flavors.

Sizes: 36g, 141g, 454g (anise); 141g, 456g (apple-banana)”

The Oxbow critical care formula is also available as a “Fine Grind“, with the same essential nutrition as Critical Care – Herbivore, but in a finer particle size.

Some recovery and emergency cases require added versatility when it comes to delivering critical nutrition.  Critical Care Herbivore – Fine Grind contains the same essential nutrition as Critical Care – Herbivore, but in a finer particle size made to flow easily through nasogastric feeding tubes as small as 5 Fr.  Because of its smaller particle size, Critical Care Herbivore – Fine Grind is ideal for use with small and young patients.

Sizes: 100g

Product Highlights:

  • Finer particle size than Critical Care
  • Powdered formula mixes easily to desired consistency
  • Highly versatile – easily flows through nasogastric tube and syringe
  • High in fiber; low in carbohydrates
  • Contains readily-absorbable chelated minerals and beneficial prebiotics
  • No refined sugars, artificial preservatives or simple carbohydrates
  • High digestibility and palatability
  • Contains stabilized form of Vitamin C


Another product which is very helpful for capybaras with less serious digestive problems is Bene-bac. Friends of mine use this whenever their capybaras become constipated or have very soft poos.

Friends of mine who live with 2 capybaras believe a product called ‘Bene-bac’ (which is a pro-biotic) is a lifesaver, and could have saved the life of their first capybara.  They use it whenever the capybara’s poos become softer and sausage shaped, rather than the encapsulated, olive shaped faeces which capybaras living in their natural habitat pass. Bene-Bac Small Animal Powder is a concentrated live culture of four common digestive bacteria found in the intestinal tracts of mammals. Bene-Bac is recommended any time an animal experiences stress from changing nutritional or environmental conditions. Contains 20 million CFU per gram of viable lactic acid producing bacteria. Powder formula is easy to mix with water.   It comes in 4 different types – the Bene-bac designed for rabbits is the correct one to use.

Constipation: Bene-bac can also be used to treat constipation. It is important to ensure your capybara drinks enough water and has access to fresh water to drink 24 hours a day. A healthy diet of unrestricted access to fresh grass should ensure a capybara does not become constipated. Chewing coarse grasses is essential for the health of capybara teeth.

Product Information

Bene-Bac® Plus Small Animal Powder is recommended any time an animal experiences changing nutritional or environmental conditions.

  • Contains seven fat-encapsulated, common microorganisms found in intestinal tract of small mammals
  • Provides help for changing conditions, including, but not limited to birth, breeding, post-surgery, antibiotic therapy, weaning, worming, showing, boarding and travel
  • Guaranteed 20 million colony-forming units (CFU) of viable bacteria per gram
  • Recommended as part of the management program for all animals subjected to adverse conditions
  • May be used for regular maintenance


Milk Formula For Baby Capybaras:

This is the only milk formula specifically formulated for baby capybaras. It has a higher protein content and fat content than other milk formulas for most other species. It comes from Australia.

Wombaroo Capybara Milk Replacer

DIRECTIONS FOR USE: To make 1 litre of milk mix 190g of powder with 870ml of preboiled warm water. Add about half of the water first, mix to a paste then make up to 1 litre with remaining water and mix thoroughly. An electric whisk can be used for mixing.

Feed Impact Colostrum Supplement to new-borns who did not receive sufficient maternal colostrum.

GROWTH & DEVELOPMENT: Typical birth weight is 1.5 – 2.0 kg. Average daily weight gain is about 50-100g per day until weaning at 3 months (approx. 8kg body weight)3 .


  • Protein 42%
  • Fat 24%
  • Carbohydrate 22%
  • Ash 6%
  • Moisture 4%
  • Metabolisable Energy (ME) 20MJ/kg

©Wombaroo Food Products, Dec 2017. 10 Oborn Rd, Mt Barker SA 5251



INGREDIENTS: Whole milk solids, whey protein, casein, vegetable oils, omega-3 and omega-6 fatty acids, stabilised vitamin C, vitamins and minerals.

TYPICAL COMPOSITION PER LITRE OF PREPARED MILK Protein83gVitamin E14mgFolic Acid1.0mgSodium500mg
Fat49gVitamin K1.0mgVitamin B1219μgMagnesium80mg
-Omega 31.4gVitamin C520mgBiotin80μgZinc5.1mg
-Omega 63.4gThiamine7.1mgCholine130mgIron5.5mg
Energy (ME)3.9MJNiacin29mgCalcium2.2gCopper0.8mg
Vitamin A470μgPantothenic Acid11mgPhosphorus1.6gIodine100μg
Vitamin D34.6gPyridoxine2.4mgPotassium1400mgSelenium25μg
TYPICAL ANALYSIS (Powder) Protein42%
Energy (ME)20 MJ/kg



The Lesser Capybara, Hydrochoerus isthmius. This species of capybara is less well-known then the larger, and much more numerous, Hydrochoerus hydrochaeris. 您知道水豚有2種嗎?這是較小的,數量少得多. カピバラには2種類あることをご存知ですか?この種は小さく、はるかに少ないです

There are 2 species of capybara, the larger Hydrochoerus hydrochaeris, which is the species we all know well, and Hydrochoerus isthmius also called the The Lesser Capybara. The 2 species look very similar. However, the Lesser capybara is smaller, with thicker and wider frontal bones. They have a slightly more angular head and a somewhat darker, brown coloured coat. The Lesser capybara weighs about 28 kg as against 40 – 60 kg for Hydrochoerus hydrochaeris. The 2 species of the genus Hydrochoerus live in habitats which rarely overlap.

Stanford 3

For an interval in the 20th century, the Lesser capybara, Hydrochoerus isthmius , was thought to be a subspecies of the larger Hydrochoerus hydrochaeris. However, genetic studies and studies of their anatomy in the mid-1980s, showed that the Lesser capybara was indeed a separate species. It’s karyotype (genetic sequence) has 2N equals 64 and FN equals 104. The karyotype of the larger Hydrochoerus hydrochaeris is: 2N equals 66 and FN equals 102.

The Lesser capybara breeds throughout the year and gives birth to 3 – 4 pups on average, as against up to 8 pups for Hydrochoerus hydrochaeris. The gestation period is 108 days for the Lesser capybara as against 150.6 days for Hydrochoerus hydrochaeris. The Lesser capybara pups at birth weigh about 1.1 kg (as against 1.5 kg for the larger capybara, Hydrochoerus hydrochaeris). As with Hydrochoerus hydrochaeris, the Lesser capybara can be diurnal or nocturnal, and social or solitary, depending on the season, the habitat and the pressure imposed by hunting.

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There is not a great deal of information about the Lesser capybara, Hydrochoerus isthmius, as relatively few studies of this species have been done. Their conservation status is not known but they may be under threat in some of their traditional habitats. Their numbers are far smaller than Hydrochoerus hydrochaeris, the larger, well-known capybara. Their population status and current distribution in Colombia is unknown.

The Lesser capybara is under threat due to subsistence hunting and the destruction of its habitat. The gallery forests where they live are being cleared and the swamp lands, vital for this semiaquatic species, are being drained. The drainage of the swamp areas bordering the Magdalena River are having a particularly detrimental effect on their numbers.

Predators include jaguars and pumas on land and Cayman in water. Additionally, young capybaras are often attacked by snakes (boa constrictors), crab eating foxes, some birds like the caracara and black vultures.

The Lesser capybara is found in the Caribbean region, the northern end of the Pacific region and the inter-Andean valleys of the Cauca and Magdalena rivers.


If you want to meet a member of this species, this is where you might be able to find them: The Lesser capybara, Hydrochoerus isthmius, is found to the west of the Andes in Panama, Colombia and Venezuela. The larger, and much more well-known species, Hydrochoerus hydrochaeris, is found in every country in South America except Chile. In these other South American countries, Hydrochoerus hydrochaeris is only found to the east of the Andes, from Venezuela in the North to the mouth of the River Plate, in Argentina. The Lesser capybara is found in Panama and this is the only country in Central America where capybaras live. Both species of capybara can be found in Colombia but the habitats in which they live are separated by the Andes; the Lesser capybara lives west of the Andes and the larger Hydrochoerus hydrochaeris lives east of the Andes. The Lesser capybara is found in northern parts of Colombia, along the Caribbean coast, the lowland headwaters of several rivers including the Catatumbo river, and the rivers to the north and west of the Sierra Nevada De Santa Marta. The Lesser capybara is also found in some valleys and in the Department of Choco. In Colombia the species is known as ponche or caco culopando, lancha and piropiro among other names. Populations of capybara in Colombia are thought to be small but there is little information available. Venezuela is the only other country where both species of capybara are found. In Venezuela, the Lesser capybara is only found around Lago de Maracaibo in Zulia state, west of the Andes. In Venezuela, as in Colombia, the 2 species of capybara are separated from each other by the Andes mountains. The 2 species are not sympatric, meaning they do not live in the same or in overlapping geographical areas.

Both species live in the same type of habitat: a wide variety of lowland habitats with access to ponds, lakes, rivers, swamps, streams or reservoirs. These habitats include gallery forests, seasonally flooded savannas and wetlands. The highest elevation where capybaras, only the larger Hydrochoerus hydrochaeris, have been found is 1500 meters in the Chapada dos Veadeiros National Park in Goias State in Brazil.

(A gallery forest is where the forested area forms a thin ribbon of trees, only a few meters wide, along a riverbank or bounding a wetland area. The surrounding area, moving away from the river or wetlands, is primarily grassland with at most a sparse scattering of trees. These gallery forests are able to exist because they draw water from the rivers. The extent of gallery forest are diminishing as a result of human activities.)

Like their larger relations, the Lesser capybara, Hydrochoerus isthmius, is semiaquatic and usually most active during the afternoon and at night to avoid predators. Capybaras have subcutaneous sweat glands which are sparsely distributed throughout the body, meaning that their ability to sweat is not well developed, so in order to control their body temperature (thermoregulate) in the heat of the day, capybaras rest in water or under the shade of trees and bushes. Capybaras also use water to escape from predators, and they prefer to mate in water. Water is also the source of their preferred aquatic plants, an important part of the capybara diet.

Capybaras tend to rest in the morning and then escape the heat of the day, in the early afternoon, by resting in water. The herd then grazes, on and off, from late afternoon until dawn. The capybara is a highly gregarious and social animal, most often found in family groups. These groups may be as small as a male capybara and one or 2 females, or larger groups of related females and a dominant male. There may also be 1 or 2 subordinate males, who are tolerated by the dominant male, because they stay on the periphery of the herd and act as lookout. Subordinate males emit the highest number of warning calls to alert the herd to possible danger. These subordinate males do mate, and the aggregate number of their matings may exceed that of the dominant male, but overall the dominant male mates the most. Female capybaras often prefer to be mated by the dominant male, so if a subordinate male is mating with her, she will often cry out, to alert the dominant male as to what is happening, so that he can come over and drive the subordinate male away. Female capybaras will also spent more time running away from, and alluding, a subordinate male who is trying to mate with them, than when a dominant male is chasing them to mate.

Capybaras are a sedentary species whose home range may extend from 5 – 16 hectares, depending on the amount of grazing available. This home range will include a large area of grassland, as grasses (and aquatic grasses) form the major part of the capybara diet, an area of slightly elevated dry land for resting, and a permanent body of water. Capybaras also live in forested/jungle habitats beside a river. In these forested habitats the family group usually consists of one male and 1 or 2 females. The Lesser capybara also eats algae.

There have been no studies indicating that interbreeding between the 2 species of capybara has taken place. However, in Colombia some capybaras of the larger species, Hydrochoerus hydrochaeris, were taken from the Orinoco River region to recreational houses in the Cauca Valley, from where they escaped into rivers and wetland areas.

Encounters between 2 species of the same genus can lead to hybridisation which may have detrimental effects on hybrid descendants. If these encounters are extensive it may result in the local extinction of both parental species. There is no evidence that this has or could happen to these 2 species of capybara, Hydrochoerus hydrochaeris and Hydrochoerus isthmius.

Scientific classification:

Kingdom: Animalia

Phylum: Chordata

Class: Mammalia

Order: Rodentia

Family Caviidae

Genus Hydrochoerus

Species Hydrochoerus isthmius

The Lifestyle a Pet Capybara Expects 寵物水豚的生活方式 ペットカピバラのライフスタイル

Written by A Couple Who Have Lived With 2 Pet Capybaras for 8 Years

By Marvin Reeder and Elizabeth Ojeda Reeder

Romeo Elizabeth's Room Marvin 21 May 2020

Romeo and Tuff’n relaxing

It has been my observation that Capybaras will rest facing in different directions. They do this in order to be alerted to the first sight of room service delivering their breakfast, or any treats that may be arriving.

Capybaras are much more intelligent than most people realise. The ability to conceptualise is considered a sign of high intelligence. Many people cannot conceptualise, but Tuff’n can! Watch him as he solves his problem

Romeo and Tuff'n in bed with Marvin – Marvin's photo

Romeo and Tuff’n sleep in the family bed with Marvin and Elizabeth every night. They would feel rejected if they were forced to sleep separately from the family

Capybara are very sensitive animals and can be highly adaptable to many different environments. They are also highly intelligent and prefer the comforts of climate control, noise deadening windows, soft cushions to rest on, a comfortable warm bed with a heated blanket and other luxurious and plush surroundings.

Romeo in front of his new LIMO 28 February 2016

Romeo waits for his chauffeur to arrive. Please note the personalised number plate:ROUS. Rodents of Unusual Size for anyone who doesn’t know!

Among the things capybaras need and expect: permanent access to a warm bath and swimming pool, their drinking water to be heated slightly, a full-time masseur, grass and mud.

Romeo and Tuff’n have their own personal vet. She comes to their home, so that they don’t have to do go through the terrifying experience of visiting a public animal hospital. If they require an operation she can anaesthetise them, safely, on the sofa. Romeo is terrified of any building which reminds him of the animal hospital. Taking a capybara to the vet is not only very stressful for the capybara, but can also present many logistical problems. Elizabeth’s sister is a vet and she has created a permanently available prescription for antibiotics in case Romeo or Tuff’n develop an infection, so that they do not have to wait even an extra hour for treatment. Many pet capybaras die because their owners put off seeking treatment due to the cost of visiting a vet who specialises in exotic animals.

Interestingly, not all capybaras require a limousine. Romeo likes to monitor the chauffeur, standing with his front legs on the console, which has been specially padded and carpeted, and whispering instructions into the chauffeur’s ear from time to time, or nibbling his ear. In a limousine Romeo is prevented from having any direct access to the chauffeur by a glass partition. Capybaras may prefer a former racing driver to be their chauffeur; someone who can react quickly to avoid danger.

Romeo Tuff'n Kitchen

Tuff’n, Romeo and Shortrib waiting hopefully in the kitchen.  Every time Romeo and Tuff’n hear sounds emanating from the kitchen, they appear, noses pointing hopefully in the direction of the food

Tuff’n has watched the humans relaxing on li–lo’s in the pool and wants the same experience. He drags his cushion to the side of the pool, jumps in the pool, pulls the cushion in, and relaxes floating:

 Capybaras are exceptionally sensitive emotionally. More so than most humans. They are very aware of the moods of the people around them and can be easily upset. As wild animals their reactions may be instinctive, having evolved over millions of years to protect them from dangers. As a human you may have no idea what you have done to upset them, and why they have suddenly attacked you, with their very sharp teeth.

Capybara teeth are so sharp that the Amerindians of South America used the teeth as a spear point.

Like all rodents, capybaras hate to be controlled. In this, they are the complete opposite of dogs and horses. If you try to control a capybara you will destroy the relationship and the capybara’s trust.

Romeo sleeping with Liz July 2020

Romeo sleeping with Elizabeth on his special bed which includes a massage facility and a choice of positions and a choice of comfort levels

I have been observing and photographing this pair of wild capybara in their unnatural environment for about eight years. It has been my observation that they can be highly manipulative and cunning animals, able to control the minds of others.

I believe that if there were a greater number of capybaras in the world, in time they would become the dominant species and all humans would be subservient to them.

Marvin’s verdict: Please don’t keep a capybara as a pet:  the capybara will suffer.

Photos by Marvin Reeder and Elizabeth Ojeda Reeder

Where Can I Pet a Capybara in America? Why Being with Capybaras Is The Best Experience in the World

If you want to spend time with a capybara, and many other exotic species, the best place I know of is Workhorse Farm in Denton, Maryland. You might even be lucky and meet some baby capybaras.


There are about 30 other species of exotic, rare and domesticated animals on this 40 acre farm including, (as well as Capybaras) camels, zebras, llamas, Asian water buffalo, kangaroos, wallabies, emus, tortoises and draft horses. You may also encounter some baby animals.


You can also tour the farm in a wagon drawn by draft horses.


Many of these animals have been rescued and are looked after by owner Nick Mielke, his family and volunteers.


These are comments made by recent visitors to Workhorse Farm:

“Amazing experience.  My boys loved it”

“We had the best time today.  Highly recommended for adults and kids.”

“Awesome place with incredible animals. a great experience for animal lovers! the owners are super friendly and make you feel right at home!”

Spending time with a capybara is the best experience I know of; in case you didn’t already realise! Capybaras are considered one of the most gregarious species by ethologists (scientists who study animal behaviour). Capybaras who are habituated to people can be exceptionally affectionate. They love to be petted and their reaction (rolling over, looking absolutely blissful and ecstatic, with their hair rising – pilo-erection) is greater than any other animal species I know of.

I have spent at least 6 months of every year for the past 7 years in the company of capybaras: mostly the herd at Nagasaki Bio Park and with my friends’ 2 pet capybaras, Romeo and Tuff’n. I spend all day every day, studying their behaviour and learning how they go about their lives and relationships with other capybaras and humans. I never get bored in the company of capybaras!

Capybaras are very sensitive emotionally, more so than most humans. This may be, in part, because of their high olfactory intelligence (sensitivity to smell). When we are stressed or unhappy our bodies produce hormones, like the stress hormone cortisol, and capybaras can smell this. If I am upset, a capybara will sense this, whereas most humans will not, and will be extra affectionate. If my friends are sick Romeo and Tuff’n will spend all day on the bed with them. If my friends suffer an injury the capybaras seem to know which part of the body is injured and will nuzzle it. When my friends’ nephews come to spend the night Romeo will stay beside them guarding them, as if he knew children need extra protection; normally Romeo would sleep on the bed with my friends.


New born baby Porcupine

Visits are by appointment only. The farm is located 3 miles from Denton, Maryland.

You can contact Nick Mielke, owner of Workhouse Farm, Rescue and Exotics, at this Facebook page:

Phone: +1 410-479-9750

Address: 25883 Garey Road, Denton, Maryland 21629


What Is Cecotrophy? Why Capybaras Eat Their Cecotropes.

Capybaras Eat Their Cecotropes to Increase the Amount of Protein and Other Nutrients They Get from Their Low Nutrient Diet.  Capybaras do not eat their faeces or their poo! They eat their cecotropes.

Io eating his cecotropes 2012

5 month old Io, Donguri’s little son, eating his cecotropes

The capybara diet is highly fibrous and nutritionally low in value. Cecotrophy allows the capybara to digest more nutrients from an otherwise low nutrient diet and maximise the absorption of protein. The ‘cecotrophy’ excreta is different in composition to the usual oval shaped faeces, and contains up to 37% more protein and 30% less fibrous material, depending on the diet. Cecotrophy in capybaras varies in frequency and it can even stop altogether when the capybara’s diet is rich in protein.

Cecotrophy is most frequent when the nutritional quality of the diet is low. In wild populations there is a higher occurrence of cecotrophy during the dry season when food is scarce and lacking nutrients. Capybaras, with their highly efficient mastication and long retention time of undigested compounds in the cecum, can efficiently digest fibrous feedstuffs. (In rabbits large particles are barely fermented and the effect of cecotrophy on fibre digestibility is low.)

It was very interesting watching Ayu. She spent a little while (5 or more minutes) eating her cecotropes. She then moved away. About 40 or so minutes later she came over to me and sat just out of reach. About 15 minutes after this she spent a similar amount of time eating her cecotropes for a second time. Then she settled down again. About 15 minutes later she passed wind, and had one last brief ‘mouthful’. This was about midday.

The average retention time of roughage in the digestive tract of capybaras is 12 (+/- 1.9) hours.

WN Syrup Cecotropes SnapShot(0)

Syrup, Maple’s 3 year old neutered male pup resting between eating his cecotropes

The process by which cecotropes are produced is called “hindgut fermentation”. Food passes through the esophagus, stomach, small intestine, where nutrients are initially absorbed ineffectively, and then into the colon. Through reverse peristalsis, the food is forced back into the cecum where it is broken down into simple sugars (i.e. monosaccharides) by bacterial fermentation. The cecotrope then passes through the colon, the anus, and is eliminated by the animal and then reingested. The process occurs 4 to 8 hours after eating. This type of reingestion to obtain more nutrients is similar to the chewing of cud in cattle.


Capybaras most often practice cecotrophy in the early morning hours when protein content is highest.

In their natural habitat, 70% of the capybaras diet consists of grasses, including aquatic grasses and sedges. Capybaras spend 31% of the day grazing during the wet season, and 42% of the day grazing during the dry season as there is less food and it is less nutritious.

Why Aoba Should Be the Next Female Capybara to Breed at Nagasaki Bio Park青葉が長崎バイオパークで交尾する次の女性カピバラにならなければならない理由. 青葉は赤ちゃんが必要です

In choosing which female capybara should breed it is important to understand the long-term consequences of this decision. The future cohesion of the herd will depend on this decision which is why it is important to choose a capybara who exhibits submissive behaviour as submissive behaviour is essential for the unity of the herd.

Aoba understands the importance of submissive behaviour. This is why Hinase has accepted Aoba. Maple’s female offspring, Milk, Cream and Butter, do not exhibit the submissive behaviour needed to ensure the unity of the herd, which is why Hinase does not accept them and is aggressive towards them.

If the future of the Bio Park herd descends only from Zabon and Maple’s offspring there will be more aggression and less cohesion. It would be a mistake to choose a female capybara to mate on the basis of her malleability, including the ability of the chief capybara keeper to interfere in the bonding process. It is important to understand that the relationship between the capybaras in the herd is the most important herd dynamic to be considered when choosing a female to breed.

WN 40% Magnificent Aoba 10 Sep 2019 034

At every zoo in Europe Aoba would be the obvious choice to breed. She is a large, very healthy capybara in her prime. She is sweet natured and intelligent. Her mother, Momiji, has invested a great deal in Aoba and the future of her bloodline. Momiji was an outstanding mother.

Momiji was a much better mother than Maple and Zabon. Momiji always gave Aoba milk whenever she demanded and allowed her to suckle for twice the usual length of time; Aoba suckled for 8 months rather than the usual 4 months. Momiji would be an outstanding grandmother and it would be a tragedy for her as well as for Aoba and the Bio Park if Aoba was not allowed to breed.

WN 40% Crop Blissful Aoba NIbbled by Babies 21 Sep 2019 006

Aoba and Zabon’s babies enjoy being together. Zabon was very thin and weak, and she had not bonded properly with her pups, so her babies went looking for other “mothers”. Alloparenting is a natural capybara behaviour and they loved Aoba.  She would be a wonderful mother

The decision to mate Zabon for a second year in 2019 was very strange, some might even say cruel, given the suffering Zabon had experienced in 2018 after she gave birth. When Zabon gave birth in 2018 she lost a tremendous amount of weight and was literally skin and bones, she also lost a lot of hair and it seemed touch and go whether she would survive. Zabon also has a chronic foot problem which requires antibiotics to treat, but because she was pregnant she could not be given antibiotics and her foot became extremely swollen and painful. It was so painful that often she was having to hop on three legs. During the later stages of her pregnancy she had great difficulty jumping in and out of the pond when she needed to thermoregulate in the heat of August.

Zabon again became extremely thin after giving birth in 2019. She was often more interested in eating or sleeping than looking after her babies.


In the photos above, you can see how extremely thin Zabon became after giving birth in 2018. She suffered so much and became very weak; too weak to look after her babies.

I have just heard that Zabon died about two months after giving birth. This tragically proves my point that no keeper with an understanding of Capybara Behaviour and Animal Welfare would have chosen to breed Zabon for a second year.

In addition, although Zabon is a very gentle capybara she comes from a very aggressive family. Zabon’s mother, Aki, was so aggressive that she became herd leader at the young age of 3. Her siblings Goemon and Yuzu were also very aggressive.

Unfortunately, Zabon’s babies seen to have inherited the family’s aggressive nature. Ko and Madoka are extremely aggressive, Ko is the most aggressive yearling capybara I have ever encountered. Sasuke and Kikyo also seem very aggressive. The last thing the Biopark needs is more aggressive capybaras.

So choosing to mate Zabon for a second year in 2019, made absolutely no sense.

Maple and her female offspring are not popular with other herd members. Butter is a bit strange, which is probably why Hinase dislikes her, therefore Butter obviously should not breed.

This is some of the submissive behaviour which Aoba exhibits: Aoba nibbles Hinase’s ear and nuzzles her under the chin, both behaviours which Hinase finds very pleasurable. On one occasion Hinase had a very painful mouth wound after Maple bit her. Hinase found some relief in rubbing her morillo which she did many more times than usual each day until the wound healed. Aoba sensed this and went over to Hinase and rubbed Hinase’s morillo using her chin. Aoba is also very sensitive to Hinase’s moods and avoids upsetting her. As a result Hinase has accepted Aoba. I have these behaviours recorded on video (see above and below).

Butter seems oblivious to Hinase’s moods and often behaves in a slightly strange way. Butter can be very aggressive and is not popular with the herd which is why she has gravitated towards humans but this does not make her a good choice for breeding.

If any of Maple’s female offspring were to be mated and become pregnant this would anger Hinase. A heavily pregnant female who is chased by Hinase runs the danger of suffering a miscarriage. ( I believe Ryoko suffered a partial miscarriage when she was frightened by one of the keepers and ran flat out to the edge of the pond. Capybaras seek refuge from danger in water. After a minute or so Ryoko lay down and then experienced three violent spasms. I said to Marc that I thought Ryoko had suffered a miscarriage; she was within three weeks of giving birth at the time of this tragedy. Her pups had to be delivered by C-section. Ryoko became so weak following this procedure that she was attacked by other herd members and she has had to be permanently separated from the herd which is tragic.)

Milk is a much more aggressive capybara than Aoba. It is only her relatively junior place in the hierarchy which keeps her aggression in check.


Hinase particularly hates Butter and frequently chases her. I can understand Hinase’s behaviour as Butter may be slightly mad. Like horses who are not popular with their herd members, Butter and indeed Maple’s other female offspring, seek out human company. This may make them popular with some people but for the future good of the herd, and the dynamic of the herd, these are not the capybaras an informed zoo keeper would choose to breed to.

Aoba comes from the best bloodline at Nagasaki Bio Park. Her grandmother was Donguri, a natural leader who avoided aggression. Donguri was also very compassionate, visiting and giving support to any capybara who had been separated from the herd and was therefore very stressed. Her offspring, Yasuo and Yasuha, and Yamato, and her grandson Choco, inherited this wise, intelligent, compassionate and non-aggressive nature.

LD WN 40% Kikyo on Aoba 01 Oct 24 2019 063

Zabon’s baby, Kikyo, loved resting on Aoba

This bloodline: Donguri, her daughter Momiji and Momiji’s daughter Aoba are likely to provide the most desirable capybaras for the future of the herd. This bloodline also includes Choco, one of the most popular capybaras at the Bio Park who pioneered several new behaviours which captivated the visitors who came to see the capybaras, many of whom came specially to meet Choco. Momiji was a fantastic mother and daughter.

Fantastic Mother Momiji Aoba

Aoba sleeping on fantastic mother Momiji

Momiji was a much better mother than Maple or Zabon. She was always watchful of her young pups and when Choco, Donut and Macaroni joined the main herd at six weeks of age, Momiji took them on a grand tour of the enclosure and the pond showing them the best places to jump out of the pond and to escape the visitors. Momiji always gave her pups milk when they demanded, no matter how greedy and demanding they were. Maple, by contrast, frequently sat on a bench high above her pups, to prevent them from being able to suckle, consequently Cookie and Butter were much smaller than Aoba even though they were a little older.


WN 40% Aoba Smiling 22 Aug 2019 028

To repeat: It Would Be Very Misguided, and a tragedy for Nagasaki Bio Park, Aoba and Momiji If Aoba Was Not Allowed to Mate.


Where Can I Pet A Capybara in England?

These are some Wildlife Parks and Zoos where you can feed and sometimes pet capybaras.

Most zoos in Britain do not allow visitors to enter the capybara enclosure.  However the number of zoos which offer the chance to be with their capybaras is increasing.

A very few zoos offer “animal encounters” where you can feed or pet the capybaras. Although some of these zoos only say that you can feed the capybaras, some people have been able to pet the capybaras as well.

jinx Shepreth

Jinx at Shepreth Wildlife Park

Having spent the past nine years studying and observing capybaras and their behaviour I have come to some conclusions: firstly, capybaras bonded with humans seem to suffer so I believe it is very important for every capybara to be bonded with other members of their species, or with other animals of a suitable species. Capybaras are an exceptionally social and gregarious species and should not be kept alone in a separate enclosure away from other capybaras.

I see no justification for a policy which prevents keepers from petting/touching the capybaras in their care. Quite the opposite. It is very important that animals/capybaras trust their keepers. One way of building up trust is for the keeper to have positive interactions with the animals/capybaras in their care. Capybaras love to be petted If they have been socialised to humans early in their life. This socialisation should take place during what is called the “critical period” which in most species occurs at about 4 to 6 weeks of age.

Building up trust and having direct contact with the capybaras allows keepers to perform healthcare procedures, and other actions, much more easily and reduces the amount of stress animals experience in these situations.

I suspect one of the reasons zoos restrict access to the capybaras, and prefer visitors to feed rather than pet the capybaras, is a fear of litigation if the capybara accidentally bites the human.

Shepreth Wildlife Park, near Cambridge.

Shepreth Wildlife Park may offer one of the best experience for interacting with capybaras.

Jinx Shepreth 2

Jinx at Shepreth Wildlife Park

In 2019 they had four capybaras: Jinx, Daze, Hex and Hoodoo.

In the words of their capybara keeper in 2019: “Hex and Hoodoo are sisters, aged 2. They are new to the park, fairly shy, and choose not to be involved in the public encounters, but watch from a distance. Daze is a male, aged 5. He is also relatively new, and initially also watched encounters from a distance, but recently has come closer, and is now able to be fed from a bowl held by visitors, but we do not touch him yet.

Jinx is the star! She is 5 years old, and is very friendly. She certainly seems to enjoy being scratched around the ears, chest and jawline, and will position herself to get the scratches right where she wants them.

Shepreth Wildlife Park offers encounters with several of our species. We believe that having the chance to experience wild animals close up allows visitors to build empathy with individual characters, which then translates to a appreciation for the species as a whole. It also allows us to fundraise for essential conservation work at home and abroad.

We offer encounters only with species that are suited to the experience, and always with ethics committee approval. The capybaras have proven an ideal species for this and the experience has proved popular with visitors. ”

The charge is £50, which as mentioned above allows the park to fundraise for essential conservation work.

For more information:

South Lakes Safari Zoo, also known as Cumbria Zoo

 Melton Terrace, Lindal-in-Furness, Ulverston, Cumbria, LA12 0LU


Telephone: (+44) 01229 466086

South Lakes Safari Zoo offers animal encounters with capybaras. The cost in 2020 was £50 per person for a visit lasting 20 – 30 minutes, and includes the opportunity to feed the capybaras.

Chessington Zoo which is part of Chessington World of Adventure in Surrey, England.

Another “animal encounter experience” with capybaras is at Chessington Zoo which is part of Chessington World of Adventure in Surrey, England.

Described as: “Hands on Feeding Experience and Learn about the World’s Largest Rodent”

For £30 you can spend 20 – 30 minutes with their capybaras, feeding them. Maximum group size is 4 people. (Long trousers and closed toe shoes must be worn.) Theme Park and Zoo entry are not included in the price.

For more information:

Tommy Lawn Cotswold 2

Tommy Lawn petting British Capybaras at a wildlife park that says they don’t do animal encounters!

Beale Park, north-west of Reading, Berkshire.

Beale Park offers an attractively priced sponsorship scheme which includes the opportunity to meet the capybara keeper by prior arrangement; they are considering including animal encounters in the future. Beale Park has two capybaras, Sharon and Gary, who were born in 2016 and are brother and sister;  like many male capybaras, Gary has been neutered.  The sponsorship scheme costs £35, lasts for 12 months and includes one free entry to the wildlife park.

For more information:

Northumberland Zoo

Address: Eshottheugh Farm, Felton, Morpeth, Northumberland, NE65 9QH

50% Northumberland zoo capybara

Northumberland zoo has a very rewarding Capybara Encounter which in 2020 cost £40 per person, for a 20 minute session with the capybaras. You will meet their family of capybaras and feed them and you will be accompanied by a zookeeper who will be able to answer all your questions about capybaras. The price includes admission to the animal park, a small capybara stuffed toy and a complimentary drink in the tearoom.

You can also become a member of Northumberland zoo and adopt an animal, both of which will give you a 10% discount on your Capybara Encounter.

You can purchase an Encounter from our online shop, in-store or alternatively, Contact Us to organise the encounter over the phone or by email. Pre-booking is recommended, but we may also have availability on the day of availability on the day of your visit, ask in the tearoom for more information.

There may be up to 2 other people taking part in the same Encounter. Regrettably this encounter is not suitable for wheelchair users.

Cotswold Wildlife Park, at Burford, Oxfordshire

10% Cotswold wildlife Park 2019

Capybaras at Cotswold Wildlife Park

Cotswold Wildlife Park has 4 capybaras, two five-year-old adults, Bell and Olly, born 14 January 2014 and 18 December 2014 respectively. The two pups, Apple and Kiwi were born on 5 August 2018.

Cotswold wildlife Park offers a 30 minute animal encounter where you can feed both the capybaras and tapirs together. I was told this is a strictly non-touching experience! Even the keepers do not touch the capybaras.  However one person I know was able to pet the capybaras here!

The encounter lasts 30 minutes and cost £50 per person.

Tommy Lawn Cotswold

Tommy Lawn at a British wildlife park

Drusillas Park, Alfriston, East Sussex

At Drusillas Park you can feed the animals in their “close encounter experiences”. The price for this experience is £80 on a weekday during term time, and £95 at the weekend or during school holidays. If there is a second person there is an extra £45 charge.


Thank you very much Tommy Lawn and Finnick Howard for their contribution to this blog.



25 Mar 2015 005 15% crop Romeo eating grass

Romeo and Tuff’n love fresh grass. They have absolutely no desire for junk food

假设要容纳一家族约 15 只水豚,展场围栏的圈地大小至少要一英亩或半公顷(约 5000 平方公尺),并依照水豚家族的成员多寡来做调整。圈地环境必须要做得像野生水豚的自然环境。

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Romeo swimming

建造一个大水池。水豚必须能自由进出水池。水池的大小至少为 4 公尺 x 8 公尺,并根据水豚家族的成员多寡做调整。原则上水池的深度应该要有 1.3 公尺,但是某些地方应该为 0.3 或 0.6 公尺的浅滩,让水豚可以浸泡在池水中休息。天气炎热的时候,水豚会进入池水中调节体温,保持身体清凉。遇到危险的时候,牠们也会躲到水中避难。被圈养的水豚可能会因为受到追逐而需要进到水中躲避攻击。此外,当水豚在受伤的状态下,也许是牙齿的根部断裂了(水豚具有高冠齿,能一直持续生长。破损的牙齿只要两个多星期就能长回来),此时居於弱势的水豚会躲到水中寻求保护。

empty pond who stole



处於寒冷气候的圈地:适合水豚生活的气候环境温度至少要在摄氏 22 度以上。如果所在地的冬天气候寒冷,圈地中必须设置具有加热器的遮蔽处,避免水豚受寒或冻伤。


草地:吃草是水豚不可或缺的日常活动。经过 2500 万年的演化,水豚的消化系统适应了以青草为主的食物,这样的食物热量低并且提供丰富的纤维素。在南美洲的自然栖地中,水豚以青草、水生植物、鼠尾草属植物为食,也会咀嚼灌木或树木的树皮。为了维持牙齿的健康状态,水豚必须咀嚼粗糙的树皮来控制牙齿的生长。在被圈养的水豚之中,曾有数起死亡案例是因为以质地柔软的食物为主而无法磨牙而导致。被圈养的动物必须要能展现自然习性才能健康成长,而吃草是水豚最重要的其中一项习性。水豚并没有演化出一日两餐的习性,牠们必须要能肚子饿了就可以自己去寻觅青草或其他适合的食物来吃。

Juanita eating grass

饮食:可以提供适当的饲料来作为补充。如果圈地中青草的份量不足以提供水豚的每日所需,则可以用其他绿色的叶类,如甘蓝叶、莴苣等可食的蔬菜叶补充。糖分含量高的蔬果不适合作为水豚的食物,此外也不应该餵食红萝卜,因为红萝卜含有丰富的维生素 A,会导致水豚的肝脏受损。在日本,许多幼年夭折的水豚正是由于肝脏受损。基於这些理由,我们也不应该餵食水果,因为水果的糖分太高了。但是可以餵食一些合适的枝叶,例如野生无花果树的枝叶。水豚喜欢啃树皮因为树皮含有丰富的营养,而且啃树皮对水豚的牙齿好处多多。Bio 3 或 Bene-Bac 之类的益生菌可以缓和轻微的腹泻。



WN scent marking capybara straddling plant for a blog
















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五大领域:1965 年,为了改善农场动物(像是应用于农业的所有动物)的处境,於是才发展出「五大自由」。「五大自由」仅强调人类的基本义务,并没有进一步确保被圈养与动物园中饲养的动物所该拥有的福利。我们需要提供这些动物愉快与正向的生活。为了让这个面向更完善,纽西兰的动物福利科学家大卫•梅勒(David Mellor)提出「五大领域」。「五大领域」的目标是要确保我们所饲养的动物拥有健全的身体与心理状态,这正是动物福利的根基与确保被圈养动物健康快乐不可或缺的基本条件。


2009 年,动物学家与动物福利科学家维琪•梅尔菲(Vicky A. Melfi)为动物园动物福利的知识与方法定出三个主要的分歧点,这里列举出与水豚饲育有关的其中两点:










Translated by Shibachi



25 Mar 2015 005 15% crop Romeo eating grass

Romeo and Tuff’n love fresh grass. They have absolutely no desire for junk food

假設要容納一家族約 15 隻水豚,展場圍欄的圈地大小至少要一英畝或半公頃(約 5000 平方公尺),並依照水豚家族的成員多寡來做調整。圈地環境必須要做得像野生水豚的自然環境。

WN Crop Aoba Milk Pond PLay 05 Jul 2017 055


水豚比人們知道的要聰明得多。看塔夫解決他的問題 水豚比人們知道的要聰明得多。看塔夫解決他的問題。











Romeo swimming

建造一個大水池。水豚必須能自由進出水池。水池的大小至少為 4 公尺 x 8 公尺,並根據水豚家族的成員多寡做調整。原則上水池的深度應該要有 1.3 公尺,但是某些地方應該為 0.3 或 0.6 公尺的淺灘,讓水豚可以浸泡在池水中休息。天氣炎熱的時候,水豚會進入池水中調節體溫,保持身體清涼。遇到危險的時候,牠們也會躲到水中避難。被圈養的水豚可能會因為受到追逐而需要進到水中躲避攻擊。此外,當水豚在受傷的狀態下,也許是牙齒的根部斷裂了(水豚具有高冠齒,能一直持續生長。破損的牙齒只要兩個多星期就能長回來),此時居於弱勢的水豚會躲到水中尋求保護。

empty pond who stole



處於寒冷氣候的圈地:適合水豚生活的氣候環境溫度至少要在攝氏 22 度以上。如果所在地的冬天氣候寒冷,圈地中必須設置具有加熱器的遮蔽處,避免水豚受寒或凍傷。


草地:吃草是水豚不可或缺的日常活動。經過 2500 萬年的演化,水豚的消化系統適應了以青草為主的食物,這樣的食物熱量低並且提供豐富的纖維素。在南美洲的自然棲地中,水豚以青草、水生植物、鼠尾草屬植物為食,也會咀嚼灌木或樹木的樹皮。為了維持牙齒的健康狀態,水豚必須咀嚼粗糙的樹皮來控制牙齒的生長。在被圈養的水豚之中,曾有數起死亡案例是因為以質地柔軟的食物為主而無法磨牙而導致。被圈養的動物必須要能展現自然習性才能健康成長,而吃草是水豚最重要的其中一項習性。水豚並沒有演化出一日兩餐的習性,牠們必須要能肚子餓了就可以自己去尋覓青草或其他適合的食物來吃。

Juanita eating grass

飲食:可以提供適當的飼料來作為補充。如果圈地中青草的份量不足以提供水豚的每日所需,則可以用其他綠色的葉類,如甘藍葉、萵苣等可食的蔬菜葉補充。糖分含量高的蔬果不適合作為水豚的食物,此外也不應該餵食紅蘿蔔,因為紅蘿蔔含有豐富的維生素 A,會導致水豚的肝臟受損。在日本,許多幼年夭折的水豚正是由於肝臟受損。基於這些理由,我們也不應該餵食水果,因為水果的糖分太高了。但是可以餵食一些合適的枝葉,例如野生無花果樹的枝葉。水豚喜歡啃樹皮因為樹皮含有豐富的營養,而且啃樹皮對水豚的牙齒好處多多。Bio 3 或 Bene-Bac 之類的益生菌可以緩和輕微的腹瀉。



WN scent marking capybara straddling plant for a blog
















20% May 16 2014 Mud 045



























五大領域:1965 年,為了改善農場動物(像是應用於農業的所有動物)的處境,於是才發展出「五大自由」。「五大自由」僅強調人類的基本義務,並沒有進一步確保被圈養與動物園中飼養的動物所該擁有的福利。我們需要提供這些動物愉快與正向的生活。為了讓這個面向更完善,紐西蘭的動物福利科學家大衛·梅勒(David Mellor)提出「五大領域」。「五大領域」的目標是要確保我們所飼養的動物擁有健全的身體與心理狀態,這正是動物福利的根基與確保被圈養動物健康快樂不可或缺的基本條件。


2009 年,動物學家與動物福利科學家維琪·梅爾菲(Vicky A. Melfi)為動物園動物福利的知識與方法定出三個主要的分歧點,這裡列舉出與水豚飼育有關的其中兩點:










Translated by Shibachi