I used to think that the paradoxical platypus and certain shrews were the only venomous mammals. But it turns out that poisons, if not venoms, are surprisingly common in mammals. A recent report in Proceedings of the Royal Society B described an African rat that uses a poison to repel lions and other pesky predators. Now Natalie Angier has a roundup of mammal bad boys, all of them dabblers in nasty toxins of one sort or another. Here’s an excerpt from The New York Times:
Venoms and repellents are hardly rare in nature: Many insects, frogs, snakes, jellyfish and other phyletic characters use them with abandon. But mammals generally rely, for defense or offense, on teeth, claws, muscles, keen senses or quick wits.
Every so often, however, a mammalian lineage discovers the wonders of chemistry, of nature’s burbling beakers and tubes. And somewhere in the distance a mad cackle sounds.
Skunks and zorilles mimic the sulfurous, anoxic stink of a swamp. The male duck-billed platypus infuses its heel spurs with a cobralike poison. The hedgehog declares: Don’t quite get the point of my spines? Allow me to sharpen their sting with a daub of venom I just chewed off the back of a Bufo toad.
Other mammals chemically gird themselves against smaller foes: Capuchin monkeys ward off mosquitoes and ticks with extracts gathered from millipedes and ants, while black-tailed deer rub themselves liberally with potent antimicrobial secretions produced by glands in their hooves. According to William Wood, a chemistry professor at Humboldt State University in California, these secretions have been shown to be effective against a broad array of micro-organisms, including acne bacteria and athlete’s-foot fungus, which could explain why teenage deer are especially diligent with the hoof-rubbing routine right before the annual deer prom.
For each newly identified instance of a chemical fix, researchers seek to identify its benefits, drawbacks and evolutionary back story, and to compare it with other known cases of chemical arms. Distinctive themes have emerged.
Read the rest of Angier’s article here.