A grown-up capybara is around 60 cm tall and can weigh up to 65 kg - more than most kids in your class. They have webbed feet, perfect for swimming, and their eyes, ears and nose are all near the top of their head so they can stay almost underwater and still see, hear and breathe.
Capybaras are famously calm and friendly. They are happy to share their space with all sorts of other animals: turtles, monkeys, ducks, cats, even crocodile-like caimans. There are countless photos online of birds sitting on capybaras' backs and even other animals napping on them. They just don't mind.
They live in groups of around 10 to 20, led by the oldest female. They eat grass and water plants and spend most of the day either grazing, lounging in the shade, or floating in the water to stay cool. They communicate in soft squeaks, clicks, whistles and grunts.
Capybaras are great swimmers. They can hold their breath underwater for around 5 minutes, which they use to nap or to hide from anything that might want to chase them. Sometimes you'll spot a whole family floating gently down a river, only their noses showing above the surface.