Why are whales so big? And why aren’t they bigger? Those are two long-standing questions for biologists, and it seems that they might have answers now thanks to sophisticated sensors which were suction-cupped onto the backs of whales.
Being large in size boosts a whales’ ability to reach more food for less effort. It helps them exploit the riches of the deep sea that other creatures can’t reach.
By estimating the energy used — and gained — when foraging for 13 species of whales and porpoises, scientists have shown that how big the creatures get is influenced by feeding strategy and prey availability.
The sizes of toothed whales like orcas, which use echolocation to hunt for individual prey, appear to be constrained by how much food they can grab during a dive, researchers report. That’s not the case, however, for blue whales and other filter feeders, which tend to be much larger than their toothed cousins. Filter feeders alive today aren’t constrained by food availability, which may mean they might be limited by their biology. Or the animals could be on their way to evolving to be even bigger, according to a study in the Dec. 13 Science.
“This is a fascinating study,” says Samantha Price, an evolutionary biologist at Clemson University in South Carolina who wasn’t involved in the research.
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(Image Credit: rmferreira/ Pixabay)