There’s no whale more famous than Moby Dick. Many of us encounter the albino sperm whale in high school English class, and if not there, then certainly in one of the many, many movie adaptations of the tale. So when two palaeontologists went about redescribing a contentious fossil sperm whale with a distorted lower jaw, it seemed only fitting to name it after the boat-smashing leviathan of page and screen.

Albicetus _skull -fossil _2015_12_16
Image: James Di Loreto / Smithsonian

Paleontologists Alexandra Boersma and Nicholas Pyenson didn’t find the new whale in ancient stone, but in the collections of the Smithsonian National Museum of Natural History

Back in 1925, whale fossil expert Remington Kellogg described an incomplete skull that had been collected from the 16 to 14 million year old rock of California's Monterey Formation in the 1800s. Because of its strange teeth, Kellogg suspected the animal was a relative of another fossil whale, Ontocetus emmonsi – which is how the California find came to be called Ontocetus oxymycterus.

But here's the twist: the original Ontocetus fossil wasn’t really a whale at all. That strange tooth turned out to be a walrus tusk! So, while still retaining its species title, the real fossil whale skull Kellogg had written up merited a second look. Ninty years after that blunder, Boersma and Pyenson stepped in.

Given that the whale is an early member of the sperm whale lineage, and the fossilisation process had slightly shifted the lower jaws to give them a “deformed” look (like that described for Moby Dick), Boersma and Pyenson thought it fitting to call the creature Albicetus, or “white whale”, making its full title Albicetus oxymycterus

Albicetus _fossil _2015_12_15
Image: A. Boersma for the Smithsonian

“The sheer size of this fossil, especially the block that preserves the skull and jaws, is impressive,” Pyenson said in a press release. “It probably weighs several hundred pounds and required a lot of muscle just to move around. It’s only with recent advancements in 3-D digitisation that we were able to capture the entire geometry of this specimen and better understand the unusual anatomy of this extinct species of sperm whale.”

Albicetus is part of a long and storied history. Even though there are only three species alive today – the pygmy and dwarf species, in addition to the regular sperm whale, or cachalot – the sperm whale family tree goes back around 25 million years. Some of these oceanic beasts, such as Zygophyseter, have even been nicknamed “killer sperm whales” for their superficial resemblance to modern-day orcas. The huge extinct sperm whale Livyatan, for example, had an impressive set of upper and lower teeth that would have given it one of the most frightening grins of all time.

Zygophyseter -varolai _2015_12_16
A cast of the skull and teeth of Zygophyseter varolai. Image: Hectonichus, Wikimedia Commons

Not that Albicetus was quite so big. Based on the relationship between skull and body size in sperm whales, Boersma and Pyenson calculate that their “white whale” would have stretched about six metres (almost 20 feet) in life. That’s less than half the size of giants like Livyatan and even today’s sperm whale, the largest toothed predator in the seas.

Nevertheless, the size of Albicetus and the fact that it had large teeth in both its upper and lower jaws suggests that, like many of its relatives, it was an orca-like hunter that chased down large prey like fish and other marine mammals. Despite the difference in size, Albicetus was every bit as fierce as its fictional namesake.


Top header image:  A. Boersma for the Smithsonian