Capybaras, the world’s largest rodents, are strict plant eaters that live mostly on grasses and water plants.1PubMed. Bacterial diversity in the cecum of the world’s largest living rodent (Hydrochoerus hydrochaeris) They are pickier than their placid image suggests, shifting to richer plants as the seasons change.2Journal of Tropical Ecology. Foraging patterns of capybaras in a seasonally flooded savanna of Venezuela And like guinea pigs, their relatives, they cannot make their own vitamin C, which shapes how they have to be fed in captivity.
What Wild Capybaras Eat Through the Year
Where water plants are available, they dominate the menu. In one wetland, water plants made up most of the diet and land plants only about 15%.3PubMed Central. Nutrition of Six Selected Neo-Tropical Mammals in Trinidad and Tobago with the Potential for Domestication Capybaras swim to their feeding spots, stay 30 to 80 minutes, dive for plants and surface to chew.4PubMed Central. Nutrition of Six Selected Neo-Tropical Mammals in Trinidad and Tobago with the Potential for Domestication On land or in shallows, a feeding capybara clips plants close to the ground with its front teeth.
Grass is the other staple. In a southern Brazilian marsh, a tall marsh grass was the top food in winter, spring and summer, with a different grass leading in fall.5Brazilian Archives of Biology and Technology. Feeding habits of capybaras (Hydrochoerus hydrochaeris, Linnaeus 1766), in the Ecological Reserve of Taim (ESEC – Taim) – south of Brazil
Grasses and water plants are fibrous and tough, unlike fruit. Some grasses also carry gritty silica that wears teeth down. They are mostly structural material, so each mouthful holds less usable energy than fruit or seeds do. A capybara has to take in a large volume and chew a lot, and it digests slowly, which is why feeding fills so much of its day.
Capybaras are not eat-anything animals. They pass over available plants for preferred ones. In the dry season, capybaras grazed reeds and a low grass about equally even though their quality differed.6Journal of Tropical Ecology. Foraging patterns of capybaras in a seasonally flooded savanna of Venezuela In the rainy season they almost ignored reeds and ate mainly a grass richer in energy and protein.7Journal of Tropical Ecology. Foraging patterns of capybaras in a seasonally flooded savanna of Venezuela The reeds had not vanished; the animals simply had a better option.
Choice is not only about nutrition, though. In another region, the plants eaten most heavily held more energy, but eaten and ignored plants were otherwise nutritionally similar.8Rangeland Ecology & Management. Forage Quality of Plant Species Consumed by Capybaras (Hydrochoerus hydrochaeris) in the Paraná River Delta, Argentina Taste, texture or plant chemistry probably also guides what they pick.9Rangeland Ecology & Management. Forage Quality of Plant Species Consumed by Capybaras (Hydrochoerus hydrochaeris) in the Paraná River Delta, Argentina
How Capybaras Digest Tough Plants
Capybaras use an enlarged fermenting pouch at the start of the large intestine to break down plants.10PubMed. Bacterial diversity in the cecum of the world’s largest living rodent (Hydrochoerus hydrochaeris) Bacteria living there digest fiber the animal can’t break down on its own.11PubMed. Bacterial diversity in the cecum of the world’s largest living rodent (Hydrochoerus hydrochaeris) The catch is that this happens after the stomach and small intestine, where most absorption takes place. The bacteria also make protein and vitamins, and much of that would simply be lost in the droppings without a second pass.
Capybaras produce two kinds of droppings: firm olive-green pellets and a paler, pasty kind.12Elsevier (Applied Animal Behaviour Science). A note on the cecotrophy behavior in capybara (Hydrochaeris hydrochaeris) The pasty kind holds on average 37% more protein than the pellets.13Elsevier (Applied Animal Behaviour Science). A note on the cecotrophy behavior in capybara (Hydrochaeris hydrochaeris) Capybaras eat these soft droppings to reclaim that protein,14PubMed. Bacterial diversity in the cecum of the world’s largest living rodent (Hydrochoerus hydrochaeris) and they tend to do it in the early morning.15Studies on Neotropical Fauna and Environment. Twenty‐four‐hour activity and Coprophagy by Capybaras(Hydrochaeris hydrochaeris)
This is normal, not a sign of illness. Cows ferment their food in a chambered stomach before it reaches the intestines, and chew cud. Capybaras, like rabbits, ferment afterward and re-eat droppings instead.
All that fibrous food also suits their teeth. The front teeth grow throughout life, and constant grinding of coarse plants keeps them worn to length. Without enough coarse food, teeth can overgrow.
When and How Capybaras Feed
Capybaras have about four bursts of activity in 24 hours.16Studies on Neotropical Fauna and Environment. Twenty‐four‐hour activity and Coprophagy by Capybaras(Hydrochaeris hydrochaeris) In the dry season three come after dark, while in the wet season they split two by day and two by night.17Studies on Neotropical Fauna and Environment. Twenty‐four‐hour activity and Coprophagy by Capybaras(Hydrochaeris hydrochaeris) At night, groups move quickly to grazing spots, keeping together with soft calls.18Studies on Neotropical Fauna and Environment. Twenty‐four‐hour activity and Coprophagy by Capybaras(Hydrochaeris hydrochaeris)
The seasonal shift follows conditions. In the dry season, heat pushes them to rest in water or shade by day and graze after dark. In the wet season, cooler weather and food in more places make daytime grazing easier, which fits the even split.
What Capybaras Eat in Captivity
A sample daily ration shows how heavily the diet leans on forage:
- A 50 kg capybara eating about 2% of body weight needs about 1 kg of feed (dry) a day.19Kiezebrink. What Do Capybaras Eat? Their Diet in the Wild and Captivity
- Browse: half, about 500 g, as leafy branches and shrubs.20Kiezebrink. What Do Capybaras Eat? Their Diet in the Wild and Captivity
- Grass: 30%, about 300 g, as grass, alfalfa and hay.21Kiezebrink. What Do Capybaras Eat? Their Diet in the Wild and Captivity
- Greens: 10%, about 100 g, as leafy greens and cabbage.22Kiezebrink. What Do Capybaras Eat? Their Diet in the Wild and Captivity
- Pellets: 10%, about 100 g, as concentrate pellets.23Kiezebrink. What Do Capybaras Eat? Their Diet in the Wild and Captivity
The 1 kg figure is dry feed, so fresh greens, which are mostly water, weigh more on the scale than their share suggests.
Hay and browse do more than fill the stomach. Coarse forage keeps the fermenting pouch working steadily, since its bacteria depend on a constant flow of fiber, and it wears down the teeth as they grow.
Fresh foods matter too. At one zoo, capybaras with hair loss and skin problems got seven extra vegetables, greens and fruits added to their diet.24PubMed. Added dietary vegetables and fruits improved coat quality of capybara in Seoul Zoo, Republic of Korea: A case study Vitamin C in their diet rose from about 300–400 to over 600 mg per kg of dry food.25PubMed. Added dietary vegetables and fruits improved coat quality of capybara in Seoul Zoo, Republic of Korea: A case study Within 6 months their coats grew thicker and glossier and they gained weight.26PubMed. Added dietary vegetables and fruits improved coat quality of capybara in Seoul Zoo, Republic of Korea: A case study
For safe choices, offer unlimited grass hay as the base. Use pellets made for herbivores, such as guinea pig or capybara feed, and avoid sugary treats and processed human food. Pet capybaras are restricted in many places, so check local laws first.
Pups nurse first but nibble grass within days, then move to hay and grass as they wean. They still need vitamin C from fresh food.
When changing the diet, introduce new foods gradually over days, because the gut bacteria need time to adjust. Watch the droppings: firm pellets and normal pasty droppings suggest it is going well, while loose droppings suggest slowing down.
Vitamin C and Other Diet Problems
Capybaras fed without vitamin C developed scurvy, a vitamin C deficiency, with sore gums and breaking front teeth, and one died.27PubMed. Scurvy in capybaras bred in captivity in Argentine Signs appeared between 25 and 104 days.28PubMed. Scurvy in capybaras bred in captivity in Argentine They also grew much more slowly, and pregnancy was affected, especially early on.29PubMed. Scurvy in capybaras bred in captivity in Argentine
Vitamin C is needed to build the protein that holds gums, skin and other tissues together, which explains why gums and teeth are hit early. It also breaks down in stored or dried food, so an old, dry diet can fall short even when it looks complete.
Watch for bleeding or swollen gums, cracked or uneven front teeth, a thin coat, hair loss or weight loss. Diarrhea or reduced appetite call for an exotic vet.
Other problems come from imbalance. Unbalanced diets are linked to tooth decay, overgrown teeth, obesity, gut inflammation and diabetes.30Kiezebrink. What Do Capybaras Eat? Their Diet in the Wild and Captivity Too much fruit may cause abnormal fermentation in the hindgut because of its sugar.31Kiezebrink. What Do Capybaras Eat? Their Diet in the Wild and Captivity
Do Capybaras Eat Crops
In Brazil, capybaras often damage farm fields.32Scientia Agricola. Damage caused by capybaras in a corn Field In one cornfield they damaged 26% of the planted area, most heavily along the field edges.33Scientia Agricola. Damage caused by capybaras in a corn Field In another farm area they favored rice when available but ate the most corn.34PubMed. Feeding behavior and crop damage caused by capybaras (Hydrochoerus hydrochaeris) in an agricultural landscape Corn and rice are grasses, close relatives of what they already eat in the wild.
Protection works best on the side facing a wetland or river. Fencing that blocks the approach, or a strip of non-crop vegetation between water and crop, can reduce how much reaches the planted rows.