About the size of a rabbit, the mouse deer is considered the smallest ruminant in the world. They are primitive herbivores that have existed for 30 million years. Its large eyes and small nose give it the appearance of a rodent, which is where its name comes from.

The fur is orange-brown. They lack horns or antlers, but in males, the upper tusks protrude and curve backwards. They are animals with a shy nature and nocturnal habits. They must hide among the vegetation to avoid falling prey to birds, snakes or mammals. They form monogamous couples. The male marks his and the female's territory with the secretion of a gland located in the jaw. The babies are born fully formed and active, and stand up after half an hour of life. The young become sexually mature at 5 months.