Squid can fly to save energy [View all]

[n2doc]

Jessica Marshall
20 February 2012



Squid can save energy by flying rather than swimming, according to calculations based on high-speed photography.

Squid of many species have been seen to 'fly' using the same jet-propulsion mechanisms that they use to swim: squirting water out of their mantles so that they rocket out of the sea and glide through the air. Until now, most researchers have thought that such flight was a way to avoid predators1, but Ronald O’Dor, a marine biologist at Dalhousie University in Halifax, Canada, has calculated that propelling themselves through the air may actually be an efficient way for squid to travel long distances.

The creatures are rarely seen flying, so some researchers argue that the mode of travel is not widespread in migration, but over years of study O’Dor has gathered hints that the behaviour is more common than was thought. Since the 1970s, he has been keeping Northern shortfin squid, Illex illecebrosus, in a 15-metre indoor pool. At first, his research team would often find dead squid around the pool in the morning, the creatures having jumped out of the water over night. “It was clear that if two or three died every night we were going to run out of animals fairly quickly,” says O’Dor. The team ultimately lowered the water level to keep the squid in.

Further evidence came from Julia Stewart, a marine biologist at Hopkins Marine Station of Stanford University in Pacific Grove, California, who uses tagging to track Humboldt squid (Dosidicus gigas). Her recent work found that they travelled faster than anyone had seen before. “The question this raised in my mind was, ‘Maybe they really are flying?’” says O’Dor.

http://www.nature.com/news/squid-can-fly-to-save-energy-1.10060