Capybaras are closely related to guinea pigs and to chinchillas. When they are full-grown, they weigh about 55 kg, or 100 pounds. The capybara's stocky body is about a meter, or 3 feet, long, and its shoulder is about 60 centimeters, or about two feet, high off the ground. Females are usually bigger and heavier than males. Capybaras have brown or reddish-brown fur. When they are old their fur is thin, their skin can get sunburned easily. Their eyes and ears and nostrils are high on their heads, so they can easily be kept above water when the capybara is swimming.