Increasing fossil finds are helping researchers understand how such early whales made their way to the continent
A restoration of the extinct whale Phiomicetus, named by paleontologists earlier this year, preying upon a sawfish.
In 1973, amateur paleontologist Peter Harmatuk found a strange tooth in the rock of a stone quarry near Castle Hayne, North Carolina. At the time, the tooth’s identity wasn’t clear beyond “mammal.” But just last year, George Mason University paleontologist Mark Uhen and colleague Mauricio Peredo published a more refined interpretation. The tooth appears to have belonged to a group of strange, long-snouted whales called remingtonocetids. Picture a large otter with a comically-long snout and you have a general idea of what these mammals looked like, creatures that were able to ply the waves as well as walk along sandy beaches. Perhaps that seems strange. Whales are most familiar to us as creatures of the sea, propelling themselves through the water with their paired flukes. Somehow, however, seal-like whales had made it to the shores of ancient North America from southern Asia.
“Remingtonocetids are thought to be coastal animals,” Uhen says, more like modern seals and sea lions. Instead of swimming straight across the ancient Atlantic, then, they may have gradually expanded their range from their place of origin near ancient Pakistan and India through Eurasia, eventually crossing a much shorter distance to northern North America, possibly in what’s now Canada, and then moving south.
Tracing the route these whales took may be difficult. Rocks of the relevant age, Uhen says, aren’t found north of New Jersey. Clues about the coastal route the otter-like whale took may have been lost due to quirks of geology. But that doesn’t mean the trail has gone entirely cold. “Undoubtedly there are more middle Eocene, semi-aquatic whales to be discovered and described in North America,” Uhen says. The fossils are relatively rare, and hard to find, but they are there. The rock formation that the new tooth came from, for example, has also yielded the remains of a protocetid—or proto whale—named Crenatocetus and fully-aquatic whales named Pachycetus and Cynthiacetus, all of which have been named since 1990.
Thanks to such finds, paleontologists have been able to outline the ancestry of today’s leviathans in greater detail, and there’s more to the story than the origin of humpbacks and bowheads. Researchers are continuing to turn up strange new species of early whales, often in unexpected places. Many early whales were not as closely bound to the land as previously thought, and finds like the remingtonocetid from North Carolina are demonstrating how a diverse array of amphibious whales were able to spread around the world.