Evolutionary throwback dolphin ready for kids of her own

Haruka the bottlenose dolphin in her tank at the Taiji Whale Museum in Taiji, Wakayama Prefecture. Unusual ventral fins can be seen on her underside about two-thirds down the length of her body. (Photo courtesy of Taiji Whale Museum)

Posted Dec 13 2009:

TAIJI, Wakayama -- Haruka, a young bottlenose dolphin being raised at a whale museum and said to be an evolutionary throwback, is ready to have little ones of her own.

The Taiji Whale Museum in Taiji, Wakayama Prefecture, is looking at coupling Haruka with a male dolphin in the spring, giving researchers an opportunity to study dolphin evolution if Haruka conceives.

Haruka has an unusual feature that makes her of particular interest to researchers: a pair of small ventral fins located close to the dolphin's genitals. They are thought to be evolutionary remnants of hind legs, used when the bottlenose dolphins' ancestors walked on land but made superfluous when the species returned to the water, making Haruka "the dolphin that returned to her ancestral roots."

"If she succeeds in mating, we can obtain detailed genetic data on the ventral fins," says Katsuki Hayashi, director of the museum.

Haruka, who was captured in the bay by local fishermen in October 2006, is now thought to be 12 years old. She is 2.92 meters long and weighs 269 kilograms. According to the museum, she ovulated for the first time in June, and then again in September and October, and has elevated levels of progesterone -- a hormone involved in the female reproductive system.

Researchers and the museum teamed up in 2008 to create the "Haruka Research Project Steering Committee," which decided at a meeting at the Tokyo University of Marine Science and Technology earlier this month that it was possible for the dolphin to reproduce. The committee established a number of research teams to study such areas as heredity, behavior and reproduction, and hopes Haruka will give them a good look at cetacean development.

Possible bridegrooms for Haruka will be narrowed down from a list of candidates being raised at the museum. Once the selection process is complete, the female dolphins currently sharing a tank with Haruka will be moved and a winning candidate introduced, hopefully resulting in a coupling and, eventually, a birth.

http://mdn.mainichi.jp/mdnnews/news/20091214p2a00m0na005000c.html