Even before hatching, some reptiles and birds can shift toward favorable
The power to cuddle up to warmth or cringe away from overheating may be widespread among reptile and bird embryos still in the egg, researchers say.
Earlier studies found two species of turtle embryos moving toward warmth or away from dangerously high heat (SN: 6/18/11, p. 9). Now tests of 12 diverse species find active repositioning, says ecologist Wei-Guo Du of the Chinese Academy of Sciences in Beijing.
Embryonic Chinese alligators (Alligator sinensis) shifted more than a centimeter toward heating pads, Du and his colleagues report in the March American Naturalist. Embryos of Pekin ducks (Anas platyrhynchosdomestica) repositioned almost a centimeter, and those of three other birds on average shifted a few millimeters. Embryos of three kinds of snakes edged several millimeters toward warmth or several millimeters