Scientists have now formed a list of special traits that could have enabled these amphibians to take over the world, using an aggressive analysis of 228 toad species, constituting nearly 43 per cent of the known toad species of the world.

Ines Van Bocxlaer, a graduate student of the Free University of Brussels, and her associates list these special traits in the February 5 issue of the journal Science.

The researchers reformed the evolutionary history of various toad traits and initiated a step to identify the ones that correlated with major expansions in a species' range. They squeezed their list of traits to seven prized qualities that together seemed to enable species to colonize a larger area than before.

The nearly 500 known species populating a wide range of habitat types possess highly diverse characteristics, and some species have a larger distribution range than others.

“When we linked adult and developmental traits with the past distribution of toads, we could see that ancestral toads having a combination of certain traits were the ones that expanded their range and spread over the world,” Franky Bossuyt of the Free University of Brussels, under whose joint supervision the study was done, told The Hindu.

One mutual feature of the wide-populating toads is the ability to live away from water instead of being in high humidity, damp and even wet places to survive.