London, July 20 - Higher temperatures near the ocean's surface propel king crabs to deeper waters, with the result that they are found near the surface only off the coasts of Japan, Alaska, and western Canada, scientists have found. Around 100 species live in the deep.

Sally Hall and Sven Thatje from the University of Southampton discovered that at temperatures of around one to four degrees Celsius, these crabs thrive, living and growing very slowly, probably to very old ages.

Only in the cooler water of the north Pacific are king crabs found near the surface. Temperatures found around some parts of the Antarctic (below one degree Celsius) are too extreme for their survival.

Elsewhere, they have to dive deep to get to the water between one and four degrees Celsius, which explains their scattered distribution.