Fossil baleen whale discovery in Japan

This video says about itself:

22 August 2017

Fossil of whale of 15 million years old reveals ancient hatcheries

A second close look at a fossil has revealed a hatchery previously unknown of an extinct whale, and potentially sheds light on how species respond to changing weather conditions. They report a careful reexamination of several fossils of an extinct whale, Parietobalaena yamaokai, which existed around 15 million years ago. Fossils had been collected over the last century from around Hiroshima, and were held at Hiwa City Museum of Natural History. When examining one of the exhibits, part of a skull, Tsai noticed that two of the bones had not completely woven, indicating that the animal must have been less than six months old when he died.

Identification of a possible breeding place of the Miocene for whales in the northern hemisphere also raises some interesting questions, he concludes. When, where and what species of whales initiated the long, annual migration between feeding and childbirth. Answers to these questions could help provide clues about the breeding grounds of modern whales whose locations are largely unknown. This, in turn, will have direct application for conservation strategies.

From ScienceDaily:

A potential breeding site of a Miocene era baleen whale

Researcher identifies evidence of a calf whale from the Miocene of Hiroshima, Japan suggesting the earliest known site for baleen whale breeding in the northern hemisphere

August 22, 2017

Baleen whales are amongst the largest animals to have ever lived and yet very little is known about their breeding habits. One researcher’s second look at previously found baleen whale fossils from Japan provides new evidence of a now long-gone breeding ground of the extinct baleen whale Parietobalaena yamaokai dating back over 15 million years.

The research published in the open-access journal PeerJ elaborates on the evidence of the presence of a very young individual of an extinct baleen whale, along with the occurrence of several fossil specimens of the same whale species. This study claims to have discovered a very uncommon case — a breeding ground for a long extinct large whale.

Researcher Cheng-Hsiu Tsai noticed the open suture in the skull of one fossil specimen, which indicates the preservation of a very young whale — under six months old, perhaps even close to a new-born calf. The fossil specimens investigated were originally found in the 20th century and are currently held at the Hiwa Museum for Natural History, Shobara, Hiroshima, Japan.

Identifying breeding grounds of living species of whales are incredibly rare, let alone for extinct Miocene species. For example, scientists are not certain where the endangered western gray whales reproduce, in turn leading to no concrete strategies to recover this critically endangered population of around 100 individuals.

The discovery of an ancient paleo-breeding site, which dates back to 15 million years ago, could provide new insights into the future of baleen whale survival. In a rapidly changing world, locating breeding sites and understanding why a breeding site disappeared may subsequently lead to information on how best to respond in order to conserve these living endangered populations.