Are there any poisonous mammals?

Venomous mammals are mammals that manufacture venom and utilize it to kill or cripple prey, protect themselves against predators or conspecifics, or in agonistic confrontations. Mammalian venoms are a diverse group with varying compositions and mechanisms of action, originating in three orders of mammals: Eulipotyphla, Monotremata, and Chiroptera. It has been hypothesized that certain Primates, a fourth order, are poisonous. Mark Dufton of the University of Strathclyde has proposed that contemporary mammalian predators do not require venom since they can kill rapidly with their teeth or claws, but venom, no matter how sophisticated, requires time to cripple prey.

Despite the scarcity of venom among extant mammals, poisonous spurs similar to those of the contemporary platypus may be found in the majority of non-therian Mammaliaformes groups. Venom is far more frequent in other vertebrates; there are many more species of poisonous reptiles (for example, venomous snakes) and fish (e.g. stonefish). Some birds (e.g., hooded pitohui) are dangerous to eat or touch, but no bird species is known to be venomous. There are a few poisonous amphibian species; salamandrid salamanders can extrude sharp venom-tipped ribs.