Sperm whales have a voracious appetite, at times devouring perhaps 220 billion pounds a year or more, roughly equivalent to the entire annual harvest of all the commercial fisheries on Earth. For the first time deep sea, predators and their prey were electronically tracked simultaneously to understand hunting behavior.
The sperm whale remains a challenge for scientists to research today. Adult males can reach 60 feet in length and females up to 36 feet, Sperm whales are the largest toothed whales, their massive head makes up to a third of their total body length. At the same time, little remains known about the behavior of jumbo squid in the wild.
So then what did the scientists do?
Randall Davis of Texas A&M University in Galveston and his team used a 25-foot carbon fiber pole to stick satellite-linked tags into the skin of five sperm whales. Marine scientist William Gilly at Stanford University and his colleagues were tagging jumbo squid in the Gulf of California at night. The tags, they used fit under squid fins, were designed to detach after two or three weeks and float to the surface and then transmit stored data to orbiting satellites.
What did they find?
Squid spent about three-quarters of their time at depths ranging from 600 to 1,300 feet, but at night, they spent at least half their time in shallower waters above 600 feet.
They come up following prey such as bioluminescent lantern fish and krill and other crustaceans. Such small marine prey species typically migrate toward the surface after dusk to feed on phytoplankton, or photosynthetic sea life, and return to deeper waters during the day to escape tuna and other predators that rely on eyesight to hunt nearer the surface.
Squid were found to often make made rapid nighttime dives from the surface to depths that whales frequent, they might be doing this to cool down. It is probably at this unexpected point that sperm whales get a chance to feed on them.
Source: MSNBC
