Amphibian Empire

Toads have “taken over” almost all of the modern world after an ancestral mutation allowed the creatures to thrive under drier conditions that their amphibian peers. “Cane toads are seemingly innocuous enough. First imported to Australia to control a beetle pest of sugarcane fields, they are now frog-marching their way across the island continent, wreaking havoc on in situ flora and fauna. The key to their domination has been protection from would-be predators and an ability to breed fast. But how were cane toads gifted with those traits in the first place? A new study published February 5 in Science aims to answer that question. Biologist Ines Van Bocxlaer of Vrije University Brussels and her colleagues analyzed the kinds of traits that allow various toad species to thrive under many conditions and thereby expand their ranges: independence from constant access to water and humidity; glands that produce poison as protection from predators (which double as water storage); and an ability to lay large amounts of fast-hatching eggs in temporary waters, among others. Perhaps most surprisingly, at least in the case of toads, bigger body size is better. Unsurprisingly, the cane toad—and many of its 500 Bufonidae family brethren—shares most of these traits, including a propensity for quick adaptation and blitzkrieg-like range expansion.”