Asia | The Javan slow loris (Nycticebus javanicus) is the subject of the first long-term study and conservation project of the poisonous primates. Status: Critically Endangered. Range: Three provinces in Indonesia. Population: Unknown; severely fragmented and believed to be decreasing. Slow lorises are arboreal primates that move quadrupedally between branches. They are nocturnal and omnivorous, feeding on plant matter and insects.