Why blue whales have become the largest animals on earth: a new theory
Blue whales are the largest animals that have ever existed on Earth. More than dinosaurs and mastodons known to science, an adult blue whale can reach 30 meters in length and weigh up to 191 tons. These animals really look like aliens from ancient times, when giants roamed the Earth. Scientists have developed a new theory about how a modern animal managed to maintain such a size.
Whales feed on krill - small crustaceans that are found in all parts of the oceans. The simplest explanation is that climate change has caused krill mass to become centralized in certain areas, and this allowed some whales to feed much more intensively than others. Jeffrey Goldbogen, head of the Stanford Whiskered Whale Laboratory, says this theory, while explaining the size of whales, does not provide any specifics. “They appeared 20 million years ago, but evolutionarily gigantism began to manifest relatively recently - 3-5 million years ago, ” says the scientist.
In his new article, Goldbogen examines a strategy in which a whale could grow from a 10-ton to a 100-ton creature in just a few million years. This immediately led him to the idea that gigantism is directly related to the ice age, which took place 2.6 million years ago. In those days, winds caused the outflow of coastal, surface water into the interior of the ocean, so that they were replaced by deep, subsurface water layers. This phenomenon is called upwelling, and it helps increase the flow of nutrients into the ocean.
The ice age led to an increase in the flow of water from the mainland to the ocean, and upwelling, in turn, filled the water with “fertilizers”. These two factors resulted in abnormal, ultra-dense krill concentrations in individual regions. “As a result, we live in an era of marine giants: modern oceans are extremely rich in areas in which krill concentration is extremely high, so huge animals do not experience food problems, ” the author of the article writes. However, he predicts that future climate change involves a decrease in both the habitat and the food supply for large marine animals, which makes them environmentally vulnerable.Do you like the article?
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