Peregocetus pacificus

I’ve mentioned before my fascination with the sea, and any creature that lives inside it. Which is why, when I heart that cetaceans (better known as whales, dolphins and porpoises) may have actually descended from four legged mammals, I had to share this with you. New research published in Current Biology reports the discovery of an entirely new species of ancestral whale. But the more interest part is that this particular whale was land going as well. In fact, they weren’t just land going, they also had hooves. This is weird, right?

Initially, whales’ ancestors resembled small deer, with four toes, each one ending in a small hoof. A fossil found in India suggests that the last whale precursors took to the water in times of danger, but came onto land in order to give birth and eat. They would spend considerable time wading in shallow water looking for aquatic vegetation and invertebrates, eventually finding small fish and amphibians. To me, this is incredibly fascinating, but does this mean they’re actually whales at all? When I think of a whale, I think of a giant animal that lives in the sea. Not something that would resemble a deer.

The oldest prehistoric whale fossils date from 53 million years ago, and were found at sites in the northern Indian Himalayas, and present day Pakistan. The fossil record tells the story of a gradual transition from wading to living most of the time in deeper water, the way that beavers and otters do, while still maintaining the ability to walk on land.

If you don’t believe in evolution, I would implore you to stop reading. Just think about how much that animal would have had to evolve over time, in order to go from a small creature whose maximum size is a deer, to a whale, which could grow up to 90 feet.

The hind limbs of 42.6m-year-old Peregocetus pacificus were not much shorter than its front legs, and it had tiny hooves on each toe and finger, suggesting that it was still quite capable of hoisting itself out of the water and trotting about on land. However, other features of the skeleton suggest that it was well adapted to an aquatic life. For example, its hind feet bones had ridges to which ligaments and tendons would attach, suggesting it had webbed feet. Its beaver-like tail bones bear signs that it was used as a powerful aid to swimming, though there is no evidence as to whether or not it had a tail fluke like today’s whales.

Over millennia, the pelvic bones uncoupled from the spine to enable more efficient swimming, while increased time in buoyant, gravity-easing water reduced the allocation of evolutionary resources to strong, weight-bearing legs. Front limbs morphed into flippers, while increasingly hind limbs shrunk and disappeared.

Science aside, this kind of transformation makes you wonder what a whale could look like in 50 million years. But if you take that even farther, it makes you wonder what any creature (human included) could look like in 50 million years. Will the Earth exist as we know it today? That might be too much for you to digest, and I can understand that, but the bottom line for me is that there is so much we don’t know about our planet and the creatures that live on it.

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