Given the diversity of lemurs on the island of Madagascar, it's not surprising that some of them have more specialized diets. Bamboo lemurs (Hapalemur sp.) are among the specialist species, their diet consisting almost entirely of bamboo. This diet results in them ingesting a considerable amount of cyanide, although the reason for their immunity to the effects of cyanide is still unknown. There are several species, the most common being Hapalemur griseus, and compared to other lemurs this species appears to be at less risk of extinction. The IUCN entry for H. griseus notes that the status of the species had not been assessed in over a decade, though, and may have changed since 1996.