Forget giant dinosaurs ruling the world – the biggest creature that has ever lived is the blue whale and it’s getting bigger.
The majestic kings of the deep only grew to their massive size relatively recently in scientific terms – that’s within the last 3 million years.
The blue whale growth spurt was triggered around that time by a change in the oceans that made more food available to support their huge appetites.
Suddenly, the oceans teemed with their favourite foods, such as krill and small crustaceans, which allowed them to balloon in size.
“The blue whales, the fins and bowheads, and the right whales – they are among the most massive vertebrates to have ever lived,” explained Nick Pyenson from the Smithsonian’s National Museum of Natural History in Washington DC, US told the BBC.
“Some of the dinosaurs were longer, but these big whales even outweighed the largest dinosaurs. And isn’t that surprising? People kind of think of gigantism as being a fact of the geologic past. But here we are, living in the time of giants on Earth.”
Whales are ancient creatures, with a bloodline stretching back around 50 million years.
Research by The Smithsonian looks at the size of 63 extinct species from 30 million years ago, including the ancestors of modern blue whales.
Ice Age triggered rebirth
Their length was projected from the head size, which is considered a good indicator of body size.
The results showed that such giant creatures were relatively recent in the whale timeline, and about 3 million years ago, smaller species started to die out as their much larger relatives began growing.
The theory is the last ice age reshaped the oceans and changed conditions in favour of the larger whales.
“Ice sheets in the north develop a lot of cold water that sinks and is then transported around the globe. And what you get are intense upwellings that bring that nutrient-rich cold water back to the surface. That allows algae to go crazy and that allows krill to feed and to form really dense aggregations,” said Pyenson.