In a study published in the journal Proceedings of the Royal Society B, a team of researchers investigated gigantism in baleen whales, the filter-feeding leviathans that include blue whales, bowhead whales and fin whales. The marine mammals became jumbo-size relatively recently, they found, only within the past 4.5 million years. The cause? A climatic change that allowed the behemoths to binge-eat.

The largest animals on the planet - evolved to gigantic sizes only about 2-3 million years ago as a result of changes in the distribution of their food in the oceans. Blue whales have a maximum recorded weight of 173 tonnes and can grow up to 29.9 metres in length. However, until a few million years ago, whales rarely grew over 10 metres.

Baleen whales' filter-feeding systems, which evolved about 30 million years ago, appear to have set the stage for major size increases once rich sources of prey became concentrated in particular locations and times of year, researchers said.