Which animal is the only known venomous primate?

The slow loris is the only known venomous primate.

Slow lorises produce a toxin from glands on their upper arms. When threatened, a loris may raise its arms and combine the secretion with saliva, creating a bite that can cause severe reactions in predators and humans. The venom’s precise effects vary, and researchers continue to study its chemistry and biological role.

Slow lorises are small, nocturnal primates from South and Southeast Asia. They move deliberately through forest canopies and feed on fruit, insects, tree gum and other foods. Their large forward-facing eyes support night activity, while a strong grip helps them cling to branches for long periods.

The venom does not make every loris bite medically dangerous in the same way, and the animals are not aggressive by nature. Several slow loris species face pressure from habitat loss and illegal wildlife trade. Their distinctive appearance has also contributed to harmful demand as exotic pets.