The fossil of the 12- to 15-foot-long Herpetocetus, thought to be the last survivor of the primitive baleen whale family called cetotheres, may be only 700,000 years old, researchers at New Zealand's University of Otago reported Thursday.
The previously youngest-known fossils of this whale were from the pre-Ice Age Pliocene epoch of approximately 3 million years ago, a time before many modern marine mammals appeared, Otago doctoral student Robert Boessenecker said.
"That this whale survived the great climatic and ecological upheavals of the Ice Age and almost into the modern era is very surprising as nearly all fossil marine mammals found after the end of the Pliocene appear identical to modern species," he said.
The emergence of modern marine mammals during the Ice Age may have happened more gradually than currently thought, he said.
"Other baleen whales underwent extreme body size increases in response to the new environment, but this dwarf whale must have still had a niche to inhabit which has only recently disappeared."