Featured Image Credit: New England Aquarium
By Kira Krall
Pinnipeds are a group of marine mammals that includes seals, sea lions, and walruses. They’re famous for their charismatic personalities as well as their prominent whiskers. These mechanosensory hairs can detect physical objects as well as the water movements generated by other organisms, even if that organism is hundreds of yards away.
One group of seals are notorious for snatching buried flatfish right from the sediment, even in murky or low-light conditions. One group of researchers at Marine Science Center Rostock has made an amazing discovery as to how the seals can do this: they can feel the fish breathing.
The Rostock team determined that the breathing movements of flatfish generate a force of about 9.8 inches per second. Eight hoses with identical flow rates were positioned around their research pool. Only one randomly selected hose would be turned on per research session, and it was up to the seasoned participants to select the hose that was generating a breathing current. The three harbor seals were trained to “select” the correct hose by hovering over it for 5 seconds.
Watch the seals in action below!
This study has discovered a predatory advantage that this species of seal has over buried prey items. It also explains why some species of flat fish have been documented holding their breath when stressed: it could be a response to those finely tuned whiskers that each seal is equipped with.
Benedikt Niesterok and his colleagues are developing an apparatus for a follow-up study. They want to determine just how sensitive the harbor seal’s mechanosensory hairs are to the minutest of underwater currents. You can read the study’s abstract and see more supplementary information here.