(JP)Trapped killer whales may have been trying to protect offspring

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http://mdn.mainichi.co.jp/news/20050302p2a00m0dm011000c.html

 

Trapped killer whales may have been trying to protect

offspring

 

Researchers trying to determine the reason why a pod

of 12 healthy killer whales became trapped in drifting

ice off Hokkaido last month, leading to the death of

nine of them, said the pod may have been trying to

protect three killer whales that had just been born.

 

One of the 12 killer whales managed to free itself

after becoming trapped in the icy waters early last

month. It is still unclear whether or not two others

are alive.

 

Autopsies on the dead whales conducted by the National

Science Museum found the bones of seals inside the

bodies of six of the killer whales, and milk in the

stomachs of two of the three infant killer whales,

suggesting that the whales had attacked and eaten

seals before feeding their young.

 

On the night of Feb. 6, the day before the whales

became trapped in the floes, a fierce north wind was

blowing. Hidehiro Kato, a researcher at the National

Research Institute of Far Seas Fisheries in Shizuoka

Prefecture, said killer whales were proficient at

avoiding danger, but the weather may have caused

unexpected shifts in the ice in the water.

 

Killer whales give birth once every four or six years.

It is rare for a pod of only about a dozen to include

as many as three young offspring. Researchers said

fully grown killer whales, which can swim at speeds of

up to 50 kilometers per hour, can make their way past

drifting ice, but young killer whales are not able to

swim as fast.

 

Kotoe Sasamori, 41, a guide on whale watching boats,

said it was possible that the three young killer

whales were unable to flee from the ice.

 

Masao Amamo, a member of the International Coastal

Research Center at the University of Tokyo's Ocean

Research Institute who participated in the autopsies

of the whales, said that killer whales do not usually

leave weak members of their pod behind.

 

" Killer whales are highly sociable, and if one or two

whales are weak, the pod doesn't leave them behind.

There are plenty of times when all whales in the pod

sacrifice themselves (to protect the weaker members). "

 

A 50-year-old cameraman who went underwater when the

whales were being lifted from the waters off Rausu,

Hokkaido, where they became trapped, said there was a

young killer whale under the body of the biggest

female.

 

" The female had died as if it was holding the young

killer whale, " the cameraman said. " It seemed like she

was trying to protect it. " (Mainichi Shimbun, Japan,

March 2, 2005)