Frogs are known to reproduce much different than humans do, spawning or laying eggs from which hatch tadpoles that later develop into froglets. There are of course some differences according to species but none reproduce like the frog recently discovered by researchers from the University of California in Berkeley.
Jim McGuire, a herpetologist from UC found this rare species as he was traveling around the Indonesian island of Sulawesi, located east of Borneo. He initially thought the frog was alone but as he picked it up, he noticed he had tadpoles all over his hand. He soon realized that it was actually a female frog with about twelve tadpoles.
This frog is a member of the Limnonectes larvaepartus species, first discovered many years ago by colleague Djoko Iskandar, a zoologist at Indonesia’s Institut Teknologi Bandung. The frog’s color can varies from gray to brown; it has a length of 1-1/2 inches and weighs less than 2/10 of an ounce. The males present two protuberances emerging from the lower jaw. These two “fangs” are used when fighting, to protect themselves from being eaten by their larger frog comrades, snakes and frog-eating birds. They live in rainforests, in the vicinity of small streams and puddles.
This was the first time scientists saw how this species actually reproduces. Out of the 6,455 frog species know all over the world, this one mates similarly to humans. Rather than laying fertilized eggs, this frog “gives birth to tadpoles as opposed to froglets or laying fertilized eggs.”
This is one of the few species (about 10) that developed internal fertilization. McGuire explained that most frogs fertilize externally. It happens as the male holds the female in an amplexus grip (the frog mating embrace) when sperm and eggs are being released.
There are numerous ways in which frogs reproduce, according to species. Some African frogs are capable of a type of internal fertilization in which froglets are born directly, without going through the tadpole stage. Others have pouches on their back, in which they carry their eggs or “brood tadpoles in their vocal sac or mouth”. Some frogs can carry tadpoles in pits on their backs.
According to McGuire, there were two species that have now gone extinct that were “famous for swallowing their fertilized eggs, brooding them in their stomach”. The females would later give birth to the froglets through their mouths.
Animals can carry many secrets. The fanged frog holds one of them. Researchers must now find out why only such a small number of frog species developed this type of reproduction.
Image Source: Channel News Asia