Could Warming Oceans Mean Smaller Whales?

History May Tell Us "Yes"

Recently scientists determined that whales many centuries ago were only about 15 feet long. Whales have evolved as one of the largest creatures on the planet.

Using fossil records from the earliest whale species to create a family tree, scientists aimed to examine the size of early whales. With computer simulations, researchers filled in the gaps between the earliest whales to today’s whales. They learned that over a few hundred thousand years or more, some whales grew much bigger, while smaller whale species became extinct.

What promoted these changes? Researches think that it was easier for later whales to find food across the ocean. Specifically, the Ice Age caused the ocean’s water circulation patters to change, thus resulting in spots in the ocean dense with whale food, as indicated by Graham Slater, professor at the University of Chicago and lead author of the study.

“If you are a whale, the easiest way to take advantage of dense but sparsely available resources is to get big,” said Slater.

Consider the baleen whale, for example. Baleen whales have no teeth. To eat, they swallow huge amounts of ocean water, which contains their food. They hunt schools of fish or swarms of krill, unlike toothed whales who hunt individual fish or squids. Scientists believe that as a result of the change in its food supply, the toothless baleen became huge. Instead of its old typical size of 15 feet in length, baleen whales now grow to 100 feet in length.

While researching whales in the modern world, scientists have learned much about changes in the ocean, expansion of ice, and circulation of water, too. As the ocean warms due to climate change, the oceans will become like they were in the past. Perhaps soon, we could see the whales return to what they once were.

[Source: Wisconsin State Journal]