When Toads Give Live Birth: Nature’s Unexpected Shortcut

Viviparity is extremely rare among amphibians, so newfound species remind us that nature doesn’t follow any rules

When we learn about amphibians in school, the story feels fixed: eggs laid in water, tadpoles wriggling around, and eventually a frog or toad hopping onto land. It’s such a classic example of animal life cycles that we rarely question it. But recently researchers found a new species of toad, from which we question what we have studied earlier.

Scientists studying amphibians in Tanzania identified 3 species, one of which is the tree toad from the genus Nectophrynoides that completely skips the tadpole stage. Instead of laying eggs, these toads give birth to live, fully formed baby toads, known as toadlets. Viviparity is extremely rare among amphibians, so newfound species remind us that nature doesn’t follow any rules.

Unlike most frogs and toads, female Nectophrynoides carry their developing young ones inside their bodies. The embryos receive nutrients internally and are born ready to survive on land. This adaptation may have evolved because these toads live in forested, mountainous regions where standing water is limited. By avoiding the tadpole stage, the young ones have a much better chance of survival.

Viviparity comes with its challenges. Carrying developing offspring requires significant energy, and females produce fewer young ones compared to egg-laying species. However, the increased survival rate appears to outweigh everything.

The discovery of live-bearing toads highlights that diversity still exists within even well-studied animal groups. It challenges the idea that amphibian reproduction follows a single pattern. As researchers continue to explore habitats, such findings remind us that evolution is full of surprises and that there is still much to learn about the natural world.

References:

1. Viviparity is extremely rare among amphibians, so newfound species remind us that nature doesn’t follow any rules.

2. https://www.sci.news/biology/three-new-nectophrynoides-species-tanzania-14339.html