Frogs mate in a position called amplexus, with the smaller male clasping the female from behind in a ride that can last two days or more. As she lays eggs, he expels sperm to fertilize them.

When Xenopus frog eggs are experimentally ruptured, their cytoplasm rearranges itself to form compartments similar to cells, according to a study published October 31 in Science. The researchers, led ...

First, eggs hatch into all sorts of creatures - insects, frogs, ducks and dinosaurs, with opportunities for lots of animal movements.