Incubating eggs of the tropical skink (Carlia longipes; pictured) at different temperatures results in hatchlings with legs adapted for different terrains.

Brett Goodman, now at the University of Adelaide in Australia, and his colleagues caught female skinks living in a mixed habitat of forest and rocks. These lizards lay clutches of two eggs, and the researchers split 76 sets of sibling eggs to incubate at temperatures reflecting either the forest floor (about 28.5 °C) or rock surfaces (about 23.5 °C).

Eggs incubated at the cooler temperature hatched into long-legged skinks that could sprint and climb more quickly than their warm-incubated siblings. When given a choice, the cool-incubated skinks spent more time in rocky areas, whereas skinks incubated at the warmer temperature had shorter legs and preferred leaf litter.

Credit: GREG CALVERT

Am. Nat. http://dx.doi.org/10.1086/673299 (2013)