We mammals haven't been good poisoners. There are a few primitive forms that secrete toxins—the platypus has poison spines, and an unusual insectivore on a few Caribbean islands, Solenodon, has grooved fangs and secretes a salivary toxin, and itty-bitty shrews have toxic saliva—but our class just hasn't had much natural talent for venom. At least, not recently.
New discoveries of some fragmentary fossils in Canada have shown that there were some flourishing species of small, poison-fanged mammals running around in the Palaeocene, 60 million years ago.
Continue reading "Bisonalveus browni, a venomous mammal" (on Pharyngula)