A porpoise, or small-toothed whale, with a long lower jaw resembling a tremendous under bite lived in the waters of California 1.5 to 5 million years ago, according to a recent study.
Scientists have discovered 15 different examples of Semirostrum ceruttii, as the species was named. With a 33-inch lower jaw -- 40 percent longer than their upper jaw --, they possess the largest under bite of all mammals.
The porpoise lived for several millions of years ("pretty successful" according to the Los Angeles Times, though I'm not so sure they've earned that distinction) on the strength of its lower jaw, extra sensitive as it brushed the ocean's surface in search of food. It acted as a replacement for the animal's poor eyesight.
The jaw was used more as a way to detect food rather than capture it. Once a fish or pretty much anything edible was in distance, the porpoise would pull its head back and use both sides of its mouth to snare the prey.
"This is unique anatomy for a mammal," said Yale University's Rachel Racicot, the study's lead author. "And it tells us that porpoises once searched for food in a very different way than they do now."
In the end, however, the porpoise's reliance on its extreme under bite may have been its undoing. According to the study, climate change about 1.5 million years ago lowered seal levels and altered the ocean's surface -- in particular a shallow area of continental shelf where the mammal preferred to hunt.
Still, scientists say they need more evidence to support the climate change theory.
