THE EVOLUTION OF A SPECIES CAN HAPPEN QUICKLY. I have always thought of the evolution of species as a process taking a long time—on a scale of tens of thousands of years. The more recent Economist article gives an example of a species developing a defense against an invasive species in less than 80 years. The cane toad, introduced to Australia in 1935, is poisonous to predators. Yet, as this wikipedia article confirms, some snake species have been reported to have already adapted smaller jaws so that they are unable to swallow large cane toads which have large quantities of poison.
The Economist article also gives an example of an evolutionary advantage that took less than 15 years: “In America, it took mussels less than 15 years to gain thicker shells that invading Asian crabs could not crack.”
A species can learn behavior quickly too, it turns out. Two species have learned to eat cane toads safely. The Torresian crow attacks the toad through the neck and avoids their glands. The Australian dwarf corcodile has learned to eat only the hind legs of the toad.
Tanner told me about a few species of possums that have extremely high resistance to the venoms of snakes within their eco systems. The snakes’ venom / possums’ anti-venom abilities have grown exponentially in this sort of arms race.