Toads have spread worldwide with the help of their poisonous glands, a recent study reveals. The analysis of 124 toad species’ DNA shows their presence on six continents, with a notable surge in East Africa.
Scientists attribute the toad’s proliferation to their toxic parotid glands, containing lethal substances that deter predators. The development of these glands millions of years ago coincided with the toads’ successful expansion to new territories, granting them a competitive advantage for survival.
The study, published in the Proceedings of the Royal Society B, highlights the effectiveness of the glands as an antipredator defense mechanism. It traces the origins of toads back to South America 61 million years ago, with subsequent migrations to Africa facilitated by various hypotheses, including rafting on vegetation mats.
The toads’ ability to adapt and thrive in new environments poses a threat to local ecosystems, as seen in the recent invasion of Madagascar by the Asian common toad. This echoes the historical introduction of cane toads in Australia, where they proliferated rapidly despite initial intentions.
Scientists express concerns about the ecological impact of invasive toad species and emphasize human activities, such as global trade, as inadvertent facilitators of their global spread. The ongoing challenge lies in managing these invasions and mitigating their consequences on native wildlife.
