Fossils Solve Question of Baleen Whales’ Evolution, Which Includes Teeth

Fossils Solve Question of Baleen Whales’ Evolution, Which Includes Teeth

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Baleen Whale

For most of the modern day whales, such as the humpback and blue whales, filtered feedings through the baleen in their mouths is a way of life. These gentle giants use the comb of baleen in their mouths in order to filter organisms in the water for food. While modern day baleen whales might consume small prey that remains behind after the water drains through what is essentially the sieve in their mouths, it seems that their ancestors may have been less than friendly in comparison.

According to a new study that was released this week, it seems that the baleen whales’ ancestor actually had teeth in their mouth, based on fossils that had been found back in 1987 and even earlier. In fact, EurekAlert! reports that these original whales did not actually have baleen in their mouths at all, and instead used teeth to most likely tear apart their prey, and it is evolution that has changed the baleen whale into a filter feeder.

While the fossil that scientists used to trace the evolution of the baleen whale may have originally been found in the late 80s, it seems that it has taken some time to completely analyze their findings and determine that the earliest whales may have been fierce predators with teeth.

Originally it was believed that the idea of filtered feedings in baleen whales may have originally begun when they still used their functioning teeth. However, based on the fossil, which is believed to be the second oldest baleen whale ever discovered, it seems that the filtered feedings did not begin until after these whales no longer had viable teeth for attacking prey.

According to Dr. Felix Marx, who apparently worked on the baleen whale study, the fossil of species which is known as llanocetus denticrenatus, “is an ancient relative of our modern giants, like humpback and blue whales; unlike them however, it had well-developed teeth used to slice prey.” While they did determine that these original whales had the deep grooves in the upper portions of their mouth which would usually house the blood vessels that supply the baleen, in these ancestral whales, the grooves were actually in a cluster around the teeth. In this area of the mouth, baleen would have been damaged by the teeth and would therefore have been unnecessary, and perhaps even in the way.

Instead of the filter that modern day baleen whales are known for, it seems that the ancestral whales simply had larger than average gums and big teeth that were used to rip into prey, and it is evolution that ultimately led to the baleen of today. The scientists behind the study believe that the large gums in these early baleen whales is what actually evolved into the baleen that modern day whales use to filter their food.

baleen whale

Ultimately, the likelihood is that these early whales were losing their teeth and went from biting and ripping their food apart, to sucking it in. This change in the way these whales would need to eat is likely what led to the development of the baleen that people recognize today in baleen whales.

While scientists have long been researching these ancient whales, it took the finding of this particular piece of the puzzle to determine that early baleen whales did not in fact have baleen in their mouths. With this particular fossil being one half of a jaw that had been found much earlier containing teeth, scientists were able to determine that baleen whales were once just as dangerous as any other predator, and it is evolution that turned them into the gentle giants they are today. In fact, these early whales were predators with teeth, who would have been just as ferocious as any other predator of the sea.

Written by Kimberley Spinney

Sources:

EurekaAlert! – Fossil find solves questions around baleen whale evolution

Featured Image Credit: Rachel Clarke’s Flickr Page – Creative Commons

Secondary Image Credit: Feist, Michael – FunnyFence’s Flickr Page – Creative Commons

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