The discovery of a giant sperm whale with 40 centimetre-long teeth has shed new light on the types of predators that once terrorised Miocene waters 12 million years ago. Named Leviathan melvillei, after Herman Melvill and his formidable white whale, L. melvillei grew to between 13 and 18 metres long, about the size of a modern sperm whale, but with one important difference – those huge four-inch-wide teeth.
Prior to this find by a team of Belgian palaeontologists on the southern coast of Peru, the only known whales of this size have been suction feeders, such as baleen and sperm whales. Without any functioning teeth in their upper jaw, these whales generate a powerful flow of water to draw in their prey (usually deep-sea cephalopods) and use small, lower jaw teeth to hold and puncture them.
L. melvillei, however, with its robust jaws filled with interlocking teeth the length of prairie dogs, appears to have been a raptorial feeder which, like the modern killer whales (Orcinus orca), would hunt down large prey, inflicting deep wounds and tearing large chunks of flesh out of their bodies. The team suggests that this prey was likely to have been smaller whales.
“We think that medium-size baleen whales, rich in fat, would have been very convenient prey for Leviathan,” said Oliver Lambert, the palaeontologist who discovered the fossil. “With its three-metre-long head, very large upper and lower teeth… this represents one of the largest raptorial predators and, to our knowledge, the biggest tetropod bite ever found.”
Somewhat similarly, another recent discovery has found that the Pristionchus pacificus, a common bacteria-eating worm, will grow a new mouth and eat other worms when starved. “Environmental factors dictate the kind of mouthparts formed by roundworms,” said Ralf Sommer, Director of the Department of Evolutionary Biology at the Max Planck Institute.
If a larval P. pacificus grows up in an environment with an abundant supply of bacteria to feed on, it develops a narrow oral cavity and very small teeth-like denticles. However, if it grows up in a heavily-populated area with limited food sources, the larvae will develop a much wider mouth filled with larger, stronger “teeth”.
This effect is also triggered by one of the worms’ pheromones, which at times of high population density, exists in increased concentrations. Situations in which overpopulation is coupled with a lack of food sees the “switching on” of a particular gene in P. pacificus , causing the development of different mouthparts.
This done, the worm will bite a neighbouring worm, tearing a hole into its side to devour its insides as they come oozing out (see image below). Unfortunately for the victim, Caenorhabditis elegans – a smaller, closely related worm – it doesn’t possess the same kind of “teeth” to defend itself with.
Yeah, so I don’t know about this. I’m not one to judge, but a whale who eats other whales? Eeesh… I mean, everyone will be out to dinner somewhere, Leviathan will be late as usual because he knows no one is going to start without him because they’re all terrified he’ll sit on them, which means they’ll probably end up inhaling half a dozen cocktails each to tide themselves over while they wait.
Then finally, finally Leviathan will saunter in, but only Megalodon will have the nerve to be like, “Dude, where the shit have you been?”
“What? I don’t know, at home, oh and the supermarket. I’d completely run out of tea. And you know how I never have any tissues? Well I–”
“‘Alright whatever, let’s just order.”
Easier said than done though, because everyone will be so drunk by this stage, having downed a ridiculous amount of mojitos on very empty stomachs, that the clupeid fish will barely be able to stop giggling long enough to say anything coherent, while the giant squid will be like, “…AND THEN HE ATE IT!! What? Oh I’ll have the crab. Wait, wait, have you guys heard the one about the two sea cucumbers in the nightclub bathroom? …THOSE AREN’T CUVIERIAN TUBULES…!”
But then it’s Leviathan’s turn to order and he’ll be like, “I’ll have the baleen whale, thanks,” and all at once the entire table will go dead quiet, except for some horrified gasps and monacles tumbling from faces and smashing on the floor, and Megalodon will whisper urgently from across the table, “For Christ’s sake, you can’t order whale.”
“What? Why not?”
“Because you’re a whale.”
“So? It’s perverse! There’s a word for people like you, you know.”
“But I eat whale all the time!”
“Well if I’d known that, I never would’ve invited you. Just order something else, people are starting to leave.”
The longfin mako sharks cancel their orders and head for the door.
“Nice to see you again. Sorry. Here, take a menu.”
“Fine. I guess I’ll have the octopus then.”
The giant octopus sitting three seats down from him will throw seven strawberry daiquiris in his face whilst motioning at the waiter, “Seven strawberry daiquiris please.”
The giant squid will suddenly fall off his chair mid-punchline.
“Actually, make that six.”
“But seriously, you guys,” the giant squid will be slurring as he straightens himself out. “You think this is bad, I once had drinks with a worm who told me he ate his wife for dinner because the delivery guy got stuck in traffic and he was too lazy to get off the couch.”
Links: Not Exactly Rocket Science for more on Leviathan melvillei
SV-POW! for more on why Leviathan melvillei might need a new name already
COSMOS Online for more on Pristionchus pacificus.
Both papers were published in Nature. Access them here and here respectively.
Images courtesy of C.Letenneur and the Max Planck Institute for Developmental Biology / Andreas Weller.