vibrissae

Finally - a chubby seal pup to lift volunteers' spirits

     tiger-vibrissae-robinlindsey
At long last, a chubby and alert seal pup is using the shoreline of West Seattle to haul out. What a welcome sight for volunteers who have looked after one emaciated pup after another this pupping season. For the second day in a row, “Tiger” hauled out yesterday morning, but was scared back into the water before the first responder could finish taping off a buffer zone on the sidewalk above him. The pup is very aware of his surroundings and activity. Like most healthy and skittish weaners, he has by now learned to be wary of people and dogs and can be easily scared from the beach.

Tiger shows off a magnificent set of whiskers which he will shed next year during his first molt. Since newborn harbor seal pups shed a long and wavy white lanugo coat inside the womb (unless born prematurely), he will not be molting his new spotted fur until next season. However, once a pup reaches a year old, he will shed all his fur and whiskers (called vibrissae) annually over a period of one-two months immediately following breeding season. It takes many months for the whiskers to reach full length again. Seals do use their vibrissae to help them locate and identify prey by sensing motion, but during the very uncomfortable molt they tend to stay onshore for the most part and rely on fat storage for energy. This is why it is critical for seals to bulk up before the late fall and winter months since their weight will drop during the molt.

Seal pups on shore briefly today and others hanging around

sealpup-tiger-buzzshaw     
Seal Sitters education and science advisor Buzz Shaw, retired zoologist of many years at the Seattle Aquarium, was out early this morning looking for a river otter family in Elliott Bay. He didn’t locate the otters, but happened to notice a harbor seal pup haul out on a small strip of beach below the sea wall. He immediately notified our first responder and hotline. The alert and seemingly robust pup wasn’t around for long, though, as the incoming tide forced him to return to the gray, rain-dappled waters of the bay. The weaned pup was nicknamed Tiger for his visible stripes that are actually blubber folds or lines (pups have them when they come out of the womb), sometimes seen on both robust pups as well as emaciated ones. It was a welcome relief to have a somewhat chunky pup for a change after so many terribly skinny ones.

Later in the afternoon, 4 pups were observed foraging along the shoreline, but none that we know of came ashore. A pup was also sighted briefly on the protected beach at Jack Block Park. Perhaps the pups are resting at night or in locations that are less visible. The good news is, however, that we have pups still hanging around West Seattle and that they seem to be actively feeding. In the photo you can see Tiger’s long whiskers which detect vibrations from prey in the water. A recent study showed that the highly sensitive vibrissae contain thousands of nerves which enable a seal not only to locate prey, but determine size and species. This is why harbor seals are very effective hunters even at night or in deep, dark waters.

     molting-seal-wdfw-blog
All of the harbor seal pups in South Puget Sound are now fully weaned. Almost all of the youngsters have left the relative safety of the rookeries to venture off on their own - and area haul-outs are full of grumpy adult seals, molting their coats and spending extended time on shore and less time feeding. While the molting process of harbor seals is not as grueling as the “catastrophic molt” of elephant seals, it is still a very trying time, particularly as winter months approach. Females who expended all of their resources to nurse pups for 4-6 weeks now face the additional physical stress of the molt. Thanks to WDFW-MMI for providing this seal cam photo of a freshly molted seal with a smooth new coat along with others who are still molting. Don’t forget to check out the WDFW seal cam webpage for a real-time look at a harbor seal haul-out and lots of informative articles and videos.

Haul-outs this time of year are not a welcoming place for new “weaners” to linger. All the more reason we need to offer them sanctuary on our urban beaches.

Wiser pups choose safer haulouts

     
Volunteers are still observing and protecting pups in West Seattle, but sometimes in less trafficked locations. Weaned pups, now older and a bit more wary of strangers, often choose safer spots to haul out and, of late, we have responded to a number of reports of pups on private beaches. The morning following Abe’s brush with an off leash dog, he was found resting on a private beach north of Lincoln Park. Later that afternoon, he showed up back at the Park for a snooze, returning to the Sound as the sun set (photo right). Abe was observed over the next few days on private beaches, but was last seen Wednesday at Lincoln Park where he spent over 12 hours on the beach and was looking a bit too thin.

New pup Joy spent Friday in the rain on a private beach south of Alki, while another pup slept safely on a platform offshore. Homeowners kept a watchful eye on the pup until she returned to the Sound late in the afternoon. We have responded to reports of two additional pups hauling out on private beaches stretching as far south as Brace Point, where many homeowners have voiced concerns about off leash dogs.

     
Spanky (left) continues to amuse everyone almost daily with his balancing act on the rocks below the seawall. A craggy rock with its easy getaway into the surf is a more attractive resting spot for an older pup than a beach crowded with people. Onlookers remain respectful of the need to stay back from the wall so that he can relax and not feel threatened. Spanky appears to be having great success foraging, producing a good blubber layer to keep him warm in the frigid waters of Puget Sound. Spanky’s long whiskers, called vibrissae, help him find food in the dark water and at night by sensing the vibration and movement of prey. One recent scientific study reveals that seals may not only be able to detect fish up to 600 feet away using solely their whiskers, but also the size and shape of prey. Researcher Wolf Hanke says, “This strongly suggests that the seal can sense different species of fish. If the seal can avoid tracking fish that are too small or too big, this saves energy” (NY Times). Each highly sensitive whisker (seals have 40-50 on each side of their snout) has up to 1500 nerves at the base. The research shows that a harbor seal’s whiskers are as efficient at detecting fish as echolocating dolphins.




visit-website-button





m-m-2x2-button

book-cover-sm




visit NOAA marine debris website