This is what it looks like when you remove the inter-digital flesh from a whale’s flipper. Amazing to see how well the pentadactyl limb is retained! pic.twitter.com/GPu602wXz5
— Dr Mark D. Scherz (@MarkScherz) September 1, 2021
Whales and humans look nothing alike. We are trunks of meat with gangly appendages and a bobbly head atop a thin neck. We stand up and walk on dry ground, and relatively speaking, we’re terrible at swimming. Sure, there are a few similarities — we breathe air and have brains and eyeballs and such — but it’s fairly obvious that humans and whales are different species. But whales did walk on land at one point in time. Not exactly whales, per se, but whales’ ancestors. It was 50 million years ago, give or take a few years, when Pakicetus, a goat-sized, four-legged creature that scientists recognize as one of the first cetaceans, cruised around with dirt beneath its feet. And after all these millions of years, you’ll be interested to know that whales have retained a bit of their ancestors’ bone structure, sort of like the Hasburg Jaw, but with less inbreeding involved.
A recent whale flipper necropsy on a Sowerby’s beaked whale shows that inherited bone structure in a pretty gory way. Under the skin of the whale’s flipper is a skeleton that’s eerily-similar to a human hand. The structure is called a “pentadactyl limb”, and despite the weirdness of it, it’s actually a familiar occurrence in many animals. It shows a common ancestor way back in time before evolution got a hold of it and morphed it into the wide variety of hands and feet we see in creatures all over the planet. The image you see above was posted to Twitter by Dr. Mark D Scherz, the Curator of Herpetology and Assistant Professor of Vertebrate Zoology at the Natural History Museum of Denmark.
“The day before my first day, I got a message from the Collections Manager for Herpetology and Mammalogy, Daniel Klingberg Johansson, that a whale had washed up and would be dissected the following day,” Scherz told IFLScience. “These rare events spark a frenzy of activity in the museum, as various researchers and assistants work together to prepare and take data on the animal.”
Evolution is smart. Over time, it picks and chooses which traits work best for a different species. Those traits are passed down and modified over the generations. “Evolution is a tinkerer,” Scherz continued. “A repurposing of an existing structure is easier and more likely than the production of a whole new structure ‘from scratch’. When the tetrapods (four-legged animals) emerged from the primordial seas, it just so happened that the most successful lineage had five fingers and toes. Flippers have evolved repeatedly in various lineages of mammals and reptiles, each time in a different way; the fundamental structure is the pentadactyl limb, but the specific structure [of the limbs] differ very strongly.”
Makes you wonder about high-fiving a whale, doesn’t it?