Seals determine prey size through their whiskers. Ever wonder why seals have such long whiskers?Researchers from Manchester Metropolitan University in the United Kingdom have found that seals judge how large or small an object is using their whiskers. By covering the eyes and ears of the seals, and having them touch a large or small disc with their whiskers and giving them a reward, the researchers found that the seals used their whiskers to measure the size of each disc.Doctor Robyn Grant said the seals “can press their muzzle on the object and by the number of whiskers it contacts, they can work out whether it's a bigger or smaller thing." Researchers think that seals use their whiskers in the wild to sense how big or small a fish is they are hunting underwater where it is hard to see.A previous study from the University of Rostock showed that seals also use their whiskers to find a bigger fish based on the trails or wake they leave in the water. Hunting for a larger fish means saving energy and time with a higher caloric pay off from eating the larger prey. Harbor seals can have between 40 and 50 whiskers on each side of their face, with about 15 hundred nerves attached to each one.