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This blog has featured posts concerning saber-toothed seals and saber-toothed marsupials but did you know that the oceans around South America once contained a saber-toothed whale? Odobenocetops lived during the Pliocene era (around 2.5 to 5 million years ago). Two similar species are known in the genus from fossils discovered in coastal Peru. An early member of the dolphin superfamily, Odobenocetops was probably more closely related to narwhals and belgugas then to modern dolphins and killer whales.
Measuring only a little longer than 2 meters (6 feet) in length, Odobenocetops was remarkable (at least among whales) for its flexible neck–which could turn 90 degrees. The powerful blunt snout of the endearing little whale suggests that it fed from beds of mollusks and other bottom dwelling shellfish, which it rasped from their shells with a muscular tongue. Additionally, the Odobenocetopsidae had echolocation abilities like modern dolphins–although probably not so amazingly precise, since the extinct whales’ echolocation melons were much smaller than those of living dolphins.
Of course the most distinctive features of Odobenocetops were their long spiky teeth running parallel along their sides. Scientists speculate that these tusks could have been used to seek food or as a sensory organ–like the narwhal’s sensitive tusk. Perhaps male whales used their tusks to battle for females, like walruses do (although they seem awfully brittle for such battles). Some males had uneven tusks. The sole known skull of a male Odobenocetops leptodon features a right-hand tusk 1.2 m (4 ft.) long, while the left-hand tusk is only 25 cm (10 in.) long. Since this is the only male O. leptodon skull currently known, it is unclear whether such asymmetry was normal.
It is striking that the whales’ saber teeth were held next to the body and it makes one think that the whale did not execute many sharp turns. A humorous but somewhat sad cartoon which I found unattributed on the web demonstrates the potential drawbacks of the Odobenocetops’ striking saber toothed design.
I have always been fascinated by saber-toothed animals. Only a few saber toothed creatures remain in today’s world (like the estimable walruses and a few tiny saber-toothed deer) but in fearsome ages past, the design was widespread. Most readers are probably familiar with the smilodons, the magnificent saber-toothed cats which hunted the megafauna of Pleistocene North and South America, however the story of the saber-toothed cats intersects the story of another giant saber-toothed predator which was nearly as fearsome and even stranger. Thylacosmilus was a genus of saber toothed marsupial predators which ruled South America during the Miocene and Pliocene. Like the smilodons, Thylacosmilidae were large, agile predators which used their long fangs to slash the throats of huge prey. Unlike Smilodons, Thylacosmilidae were marsupials which gave birth to a tiny helpless larva which they then nurtured in a pouch.
The prominent teeth of Thylacosmilus were a result of convergent evolution and the creatures did not share any direct ancestors with cats since the divergence of placental and marsupial mammals (deep in the depths of the Mesozoic). Thylacosmilus’ teeth were also different in that they continuously grew throughout the animal’s life. The teeth were probably worn down as the predators gnawed on bones. Additionally Thylacosmilidae possessed scabbard-like bone flanges built into its lower jaw to protect its teeth (a feature missing entirely from Smilodons). Who knows what sort of noises Thylacosmilidae made with these peculiarly shaped mouths? For millions of years Thylacosmilidae lorded over the strange mammals of South America. The glyptodonts (and possibly other armadillos) developed their armor to ward off the mighty beasts. However the fickle play of tectonics undid the mighty killers.
In the beginning of the Pliocene, a land bridge joined North America and South America and suddenly the true cats arrived on what had been an island continent. As the climate dried out, Smilodons competed directly with Thylacosmilidae. Strange new herbivores appeared to displace the old prey animals. The Great American Interchange of long sundered mammalian lineages proved too much for the saber toothed marsupials. Thylacosmilidae were giant and fierce but they were no match for invasive cats.