What amazes friends and neighbours who comment on the bearded seal that was identified in Courtmacsherry Bay early this month is that it has been resident here for up to two years.
Willie O’Driscoll of Kilbrittain, a local farmer, has regularly seen the animal over that period, an Arctic species only once before recorded in Irish waters. However, it was not identified until Paul Connaughton of Shearwater Wildlife Tours, spotted it. Finding it over 2,000km south of its native habitat was a surprise, made more extraordinary by its confirmed presence over two breeding seasons. What would have kept it here? Having swum so far south, it could presumably have found its way home at will; the Arctic ocean is not an
obscure creek. Close viewing indicates a fit and healthy animal. As males are the wanderers, it is almost certainly
a young male. My guess is that he has stayed in the bay because food is abundant, mullet, crustaceans and shellfish. He is under no threat from polar bears, orcas or walruses, and there is no noise pollution which would drown out his submarine love songs (or love wails) were he to voice them. However, male bearded seals do not become sexually mature until they are six or seven years old. Therefore, he has not felt the taispe, and has not headed north where he might have to go no farther than Greenland to find a mate. Males each have a personal song. Eskimo hunters follow the sound of their singing to hunt them. Their skins, tougher than those of other seals, are favoured for boots and for covering wooden-frame boats, called umiaks. He is an endearing looking animal, with his large, morose looking whiskers and expression that might be called hangdog. With his large dark eyes set in deep, white fur, and his hint of cuddliness, children might think they would like to hug him like a giant soft toy. When his whiskers are dry and curly, he looks almost debonair, a ‘lady’s choice’ among seals.
In zoological descriptions, the head is described as often reddish-brown above a greyish-white body; however, this animal is very white, with no sign of the regular dark stripe or occasional black spots along the back. The animal’s youth would preclude a suggested explanation for his extended stay, namely that he found a mate in the colony of grey seals that thrives
on Horse Rock, a kilometre beyond his favourite roost on the bay shore. Despite similarity in size and weight, this it is extremely unlikely.
There are no records, that I can find, of bearded seals interbreeding
with any other seal species. Other
seal types have interbred but not
Erignathus barbatus (the ‘eri-gnatus’ referring to the heavy jaw, and the ‘barbatus’ to the whiskers).
Ringed seals have sometimes bred with ribbon seals, and harp seals with hooded seals. The habitat of all these species is within the Arctic Circle. Our familiar seals, the Atlantic Grey and the Common or Harbour
Seal remain around the British and Irish islands and, in a sealtrackucc.ie census, number about 3,000 plus, and 6,000 plus. A small Grey Seal colony exists in Arctic Norway.
Not only have some seal species been proven to sometimes hybridise but the warming oceans and melting of sea ice has removed barriers between species and there is evidence that other animals have also interbred.
A bear of mixed grizzly and polar bear ancestry was shot by hunters in 2006, and there have been other confirmed sightings. Polar bears may be driven south by the melting ice caps and grizzlies wander north with the the rising temperatures. Normally polar bears species stay, largely, on sea ice and grizzlies on land.
Hybridisation has also been
recorded amongst marine animals, namely beluga whales with narwhals, bowheads with right whales, and
harbour porpoises with Dall’s
porpoise. The results are physically visible, even without DNA evidence.
The aforementioned bear’s pelt was a mixture of brown and white. Polar bear–grizzly hybrids in a German zoo showed abilities for seal hunting but not the swimming abilities of polar bears. A cross between a narwhal and a beluga whale spotted in Greenland lacked the narwhal’s spiral tusk, thought to be a feature relating to breeding success. In the magazine Nature, the ecologist Brendan Kelly of the Alaska National Marine Mammal Laboratory listed
34 possible hybridisations between
distinct populations or species of
Arctic marine mammals, many of them endangered.
For example, North Atlantic right whales, which have never strongly
recovered from being the prime target in whaling days and number less than 500 may, for want of mates, be interbreeding with the more numerous bowhead whale. Hybrids could begin to outnumber the right whales, leading to their extinction.
© Irish Examiner Ltd. All rights reserved