University of California, Berkeley, herpetologist Jim McGuire was slogging through the rain forests of Indonesia's Sulawesi Island one night this past summer when he grabbed what he thought was a male ...

The antiarch fish, a type of placoderm, was the first species to reproduce by internal fertilization—and it did so sideways, "square-dance style." The fishes' interlocking arms help the male ...

"In species with internal fertilization -- like mammals, birds and insects -- sperm fertilize eggs inside the female's body, while in species with external fertilization -- like sea urchins and many ...

Evidence of bony organs in ancient, armour-plated fish suggests that they copulated even though many of their descendants stopped doing so. The history of sex may have to be rewritten thanks to a ...

Frogs exhibit an amazing variety of reproductive behaviors, ranging from brooding their eggs in their mouths to carrying tadpoles on their backs. Fewer than a dozen species of 6,000+ worldwide have ...