What does the temperature of a compost heap have to do with a
baby's sex? As many gardeners know, a well-tended compost heap
generates considerable heat as the mound of organic material
decays. Ever wonder who invented this gardener's aid? Well, it
just might have been a crocodile! A female crocodile or
alligator doesn't sit on her eggs to keep them warm. She covers
them with soil and vegetation, and as this material starts to
"compost," the nest mound heats up. But don't think the
temperature of an alligator nest is a trivial matter. The nest
is made with just the right mixture of mud and vegetation to
create a precise range of internal temperatures. Why so
specific? Because the sex of hatchling crocs and gators is
determined by the temperature within the nest! Eggs incubated at
around 89 degrees Fahrenheit produce females, while those at
temperatures below 87 degrees produce mainly males. In a well-
constructed croc nest the eggs on top will be a few degrees
cooler than those closer to the bottom, and -- VOI