Rodents, which are classified into the order Rodentia, make up the largest group of mammals, with a combined total of 2,277 species. Comprising about 40% of all mammal species, rodents have become a diverse and widespread army. Rodents are characterised by a single pair of continuously growing incisors on the upper and lower jaws and have adapted to thrive in a plethora of distinct habitats. From towering forests to underground tunnels, from barren deserts to hostile rivers, rodents have dominated every continent on earth, except Antarctica.
The capybara (Hydrochoerus hydrochaeris) is a prime demonstration of rodents’ profound adaptability. Capybaras are the largest rodents in the world. Sheep-sized guinea pigs, they have semi-aquatic lives in the swamps and forests of South America. Their streamlined bodies, coarse fur and partially-webbed feet are all adaptations to living in swampy habitats. Their nose, eyes and ears are all located near the top of their head to stay vigilant whilst swimming.
Capybaras need to stay alert, for their large size and docile behaviour attracts predators from across the Amazon. They are a favourite food of jaguars, cougars, ocelots, caimans and anacondas. Young capybaras are even more vulnerable, being targeted from the sky by eagles and vultures. The fact that capybaras provide for such a vast array of predators gives them huge importance to the ecology of the Amazon rainforest and the whole of South America – which is under dire threat due to deforestation, mining and unsustainable agriculture.
Herbivores, capybaras feed mainly on grasses and aquatic plants. Their diet may not seem unique, but capybaras are autocoprophagous. This means that they eat their own faeces. Carrying out this peculiar, and rather gross, activity gives them a source of bacterial gut flora to help digest the cellulose in their grass-heavy diet. It also allows them to extract the maximum amount of nutrients from their food.
A gregarious species, capybaras usually live in large herds of 10-20 individuals, although some groups can contain up to 100 members! Females have one batch of four to five offspring every year at the end of the wet season, when the grass is most nutritious. The mother then has the difficult job of protecting her young from the many threats they will face.
Thankfully, as a whole, capybaras are not considered a threatened species. However, they are hunted excessively in some areas for their meat and skin, resulting in the loss of some local populations. The survival of the capybara is vital to the survival of countless other species of which they provide for.
Hennessy, K., Wiggins, V. (2014) Animal Encyclopedia: The Definitive Visual Guide. 2nd edn. London. Dorling Kindersley.