A tug of war between survival and fitness: How chameleons become even brighter without predators around
Invasive species offer a rare research opportunity, as they often colonize new environments very different to their native habitat. One such species is the Jackson's three-horned chameleon (Triocerus j. xantholophus), which ...
Our study, published today in Science Advances, shows Hawaiian chameleons display much brighter social signals than individuals from their native habitat range in East Africa—and could represent an example of rapid evolution.
A long way from home
In 1972, about 36 Jackson's chameleons made their way from their native Kenya to the Hawaiian island of Oahu, destined for the pet trade.
The chameleons were a little worse for wear by the time they arrived in Hawaii, following a long and taxing journey that would have begun days before they were loaded onto the plane in Nairobi.
The story goes that an Oahu pet shop owner, Robin Ventura, opened the crate in his garden to give them fresh air and an opportunity to recover. Presumably, he underestimated the speed with which chameleons can move (and recover)—and they quickly dispersed into the surrounding area.
This founding population represented an accidental invasion, and subsequently became an unplanned experiment in evolution. What happens when an animal with colorful social displays—from a population with lots of bird and snake predators—is introduced to an island virtually free of predators?
Many lizard species, such as this Augrabies flat lizard, have bright colours on body parts that are less visible to predators such as birds. Credit: Martin Whiting