Peripatus is a genus of Onychophora (velvet worms). It is a invertebrate which gives birth to live young rather than laying eggs. It is said to be a living fossil because it has been unchanged for approximately 570 million years. This unique animal has the appearance of a caterpillar with its many pairs of legs, while its structure has many similarities to arthropods, but it also has many similarities to annelids, with some special features all of its own.