Sperm whales found traveling together, dining alone

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A new study has shown that when a group of sperm whales travel, the highly social creatures tend to stay close together.

Researchers from Oregon State University (OSU) and the Autonomous University of Baja California Sur in Mexico reported that sperm whales spend around 30% of their time on the water's surface resting and socializing.

However, when a group of whales with 27 Advanced Dive Behavior (ADB) tags would dive in search of food, they would sometimes reach a depth of 1,500 meters, or nearly a mile below the surface, and each went their own way.

During one such dive, according to researchers who recently published a paper in the journal Ecology and Evolution, a whale remained submerged for more than 77 minutes in the Gulf of California.

The sophisticated ADB tags allowed researchers to gather unprecedented amounts of data on sperm whale movement, socialization and feeding and diving behavior that previously had been difficult, if not impossible, to obtain.

Sperm whale photo from February 2009 field season in the Gulf of California, Mexico to resight tagged animals. /Oregon State University Photo

Sperm whales have been notoriously hard to study, in part because they spend a lot of time underwater and dive to great depths.

Technological limitations had precluded researchers from gathering continuous behavior data on them for more than 24 hours at a time until the ADB tags were developed by OSU and Wildlife Computers.

The tags can record high-resolution diving depth data as well as Global Positioning System (GPS) locations and enable researchers to track individual sperm whales for as long as 35 days.

The researchers discovered that whales make six different types of dives, including two shallow dive types and four deep dives.

About three out of every four dives were deep dives, likely related to foraging, and tracked sperm whales diving to the ocean floor, a more common occurrence than scientists previously thought.

"This information is extremely valuable as it reveals how sperm whales allocate their energy resources to different activities such as feeding, resting and socializing over time," Ladd Irvine, a researcher with OSU's Marine Mammal Institute in Newport, Oregon, and lead author of the study, said in a news release.

(Top photo credit to Oregon State University.)

Source(s): Xinhua News Agency