June 22, 2010 Millions of years before humans began battling it
out over beachfront property, a similar phenomenon was unfolding
in a diverse group of island lizards. Often mistaken for
chameleons or geckos, Anolis lizards fight fiercely for
resources, responding to rivals by doing push-ups and puffing
out their throat pouches. But anoles also compete in ways that
shape their bodies over evolutionary time, says a new study in
the journal Evolution. Anolis lizards colonized the Caribbean
from South America some 40 million years ago and quickly evolved
a wide range of shapes and sizes. "When anoles first arrived in
the islands there were no other lizards quite like them, so
there was abundant opportunity to diversify," said author Luke
Mahler of Harvard University. Free from rivals in their new
island homes, Anolis lizards evolved differences in leg length,
body size, and other characteristics as they adapted to
different habitats. Today, the islands of Cuba, Hispaniola,
Jamaica and Puerto Rico -- collectively