New study demonstrates how whales protect their brains while swimming
The researchers gathered biomechanic information from 11 cetacean species, such as fluking frequency, and fed them into a computer model.
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.
They found that the marine mammals became colossal only relatively recently, within the past 4.5 million years. The cause? A climatic change that allowed the behemoths to binge-eat.
Whales began as land-dwelling, hoofed mammals some 50 million years ago. Over several millions of years, they developed fins and became marine creatures. Between 20 million and 30 million years ago, some developed the ability to filter-feed, which meant they could swallow swarms of tiny prey in a single gargantuan gulp.
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But even with this feeding ability, whales remained only moderately large for millions of years. Researchers at the Smithsonian Institution’s National Museum of Natural History measured over 140 museum specimens of fossilised whales and plugged the data into a statistical model.
It showed that several distinct lineages of baleen whales became giants at about the same time, starting around 4.5 million years ago. This period coincided with the time when ice sheets first began to cover more and more of the Northern Hemisphere.
Run-off from the glaciers would have washed nutrients such as iron into coastal waters, and intense seasonal upwelling cycles would have caused cold water from deep below to rise, bringing organic material towards the surface.
Throngs of zooplankton and krill would have gathered to feast on the nutrients, forming vast dense patches. The oceans thus became “all you can eat” buffets for the whales.
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