Seals use whiskers to track prey in deep ocean, study shows

After observing the sea mammals in their natural habitat, a study has confirmed that seals use their whiskers to track down their prey.

Animals have come up with a variety of ways to live and hunt in the dark depths of the ocean. echolocation is the art of sending out clicky noises into the water and listening to their echo to locate their prey. Deep-diving seals who don't have acoustic projectors must have learned to use another technique.

Scientists have long believed that the secret weapons are their long, cat-like whiskers, since they have conducted over 20 years of experiments with artificial whiskers or captive seals blindfolded in a pool.

According to Taiki Adachi, an assistant project scientist at the University of California, Santa Cruz, a study may have confirmed the hypothesis. Adachi and his team positioned small video cameras with night vision on the left cheek, lower jaw, back and head of five free-ranging northern elephant seals. During their seasonal migration, they recorded nine and a half hours of footage.

Adachi and his team positioned small video cameras with night vision on the left cheek, lower jaw, back and head of 5 free-ranging elephant seals in Ao Nuevo State Park. During their seasonal migration, they recorded nine and a half hours of footage.

By analyzing the videos, the scientists found that diving seals held back their whiskers for the initial part of their dives and then rhythmically whisked their whiskers back and forth, hoping to sense any water movements of swimming prey. The elephant seals like to snack on squid and fishes. The whiskers were curling back towards the face as they swam back to the surface.

For less than a quarter of the time the seals hunted, they were able to see bioluminescence, the light that some creatures deep underwater can emit thanks to chemicals in their bodies. According to Adachi, they were probably just using their whiskers for the rest of their hunting spree. Adachi notes that this technique isn't different to rodents. The whisking speed in elephant seals is slower than it is in the air.

The researcher who was not involved in the study said that it made sense. The elephant seal is found at the same depths as sperm and beaked whales.

The director of the Marina Science Center at the University of Rostock welcomed the findings but was cautious about how much new information they represented. According to Dehnhardt, his group showed more than 20 years ago that seals can use their whiskers to detect and follow fish.

The study is interesting from a technical point of view, but there is still too much speculation. If the seals wore a machine that could measure the movement of fluids, it would be a great story.

Adachi wants to compare how other mammals use their whiskers in order to understand how whiskers have shaped the habits of the animal kingdom.