Venomous mammals

Venomous mammals are animals of the class Mammalia that produce venom, which they use to kill or disable prey, or to defend themselves from predators or conspecifics. In modern nature, venomous mammals are rare. Mammalian venoms form a heterogeneous group having different compositions and modes of action and are present in three orders of mammals, Insectivora, Monotremata, and Chiroptera. A fourth order, Primates, is proposed to have venomous representatives. To explain the rarity of venom delivery in Mammalia, Mark Dufton of the University of Strathclyde has suggested that modern mammalian predators do not need venom because they are able to kill quickly with their teeth or claws, whereas venom, no matter how sophisticated, requires time to disable prey.

In spite of the rarity of venom among extant mammals, venom may be an ancestral feature among mammals, as venomous spurs akin to those of the modern platypus are found in most non-therian Mammaliaformes groups.

Venom is much more common among other vertebrates; there are many more species of venomous reptiles (e.g. venomous snakes), and fish (e.g. stonefish). There is no known species of venomous bird. However, some birds are poisonous to eat or touch, and Sinornithosaurus, a dinosaur related to birds, may have had a venomous bite. There are only a few species of venomous amphibians; certain salamandrid salamanders can extrude sharp venom-tipped ribs.

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