A Somersault for Spawning
The Surinam toad, Pipa pipa, is a fully aquatic amphibian that has an exceptionally flat body, perfectly resembling a dead leaf on the bottom of slow-moving streams in the Amazon Basin. This camouflage hides it from predators, but its reproductive method is is its reproduction. Mating begins when a male approaches a female and grasps her in a position called inguinal amplexus, wrapping his forelimbs around her waist. He signals his intent not with croaks, but with a series of sharp, metallic clicks produced by snapping the hyoid bone in his throat.
What follows is a complex underwater sequence. The pair performs a series of 15 to 18 vertical loops or somersaults. As they float upside down during these arcs, the female releases a small clutch of 3 to 10 eggs. These eggs land on the male's belly. As they complete the loop and turn right-side up, the male fertilizes the eggs and gently rolls them onto the female's back. The process is repeated for hours until 60 to 100 eggs are securely in place. A sticky secretion helps the eggs adhere to her dorsal skin, which has become soft and swollen in preparation.
Honeycomb Horrors and Froglet Eruptions
Over the next few days, a transformation occurs. The female’s skin grows up and around each individual egg, completely enclosing them in a thick honeycomb-like layer of cutaneous pockets. Each egg develops in its own protected chamber, sealed with a horny lid. This unique form of gestation lasts for three to five months.
The Surinam toad completely bypasses the free-swimming tadpole stage. Inside their individual pods, the embryos develop through the larval phase, even growing temporary tails used for oxygen uptake. When development is complete, they are not tadpoles, but fully formed, miniature versions of their parents, each about 2 centimeters long. The young toads begin to push and squirm, and soon the skin on the mother’s back ruptures. One by one, the toadlets erupt from their individual chambers and swim away to begin their solitary lives. After the last toadlet has emerged, the female sheds the pitted layer of skin from her back and the process can begin again.