According to the National Wildlife Federation, the animals that eat lemurs are primarily fossa, which is a relative of the mongoose that lives in Madagascar. However, recently humans have also started to eat lemurs, due mostly to poverty.
Lemurs are primates classified as prosimians, which means that they came before other primates and monkeys. These animals live only in Madagascar and a few surrounding islands, descendants of a primate that hitched a ride to the island millions of years ago. There is even an extinct species of lemur that weighed as much as a gorilla, although now the biggest lemurs are the size of a house cat.
The fossa, which is the main predator of lemurs, has a feline appearance, although it is really related to a mongoose. This animal can climb trees, which puts the tree-dwelling lemurs in danger, and has sharp claws and teeth. It is also evolved from an ancestor that came from mainland Africa. Earlier species used to be large -- about the size of a lion.
Humans in Madagascar have also started hunting lemurs for their meat because of the poverty of the island. This puts many of the endangered lemur species even more at risk.