The seal’s torpedo-shaped body and its broad flippers make it an adept swimmer, and its thick layer of blubber protects it from the cold. Its big eyes, which are very sensitive to light, enable the seal to see under the water, and its whiskers help it sense even the smallest movements from fish. Seals can easily stay under water for several minutes, because their large bodies store and save oxygen. However, they still need to seek land every now and then. It can sleep in the water, but in order to rest properly, it must be on land. This is why you often see seals lying on the sand banks in the Wadden Sea.
The seal population in Denmark has been hit by seal plague twice, once in 1988 and once in 2002. On both occasions approximately 50-60% of the population was wiped out. Seal plague is a virus that attacks the seal’s immune system and leaves the animal susceptible to bacteria-borne infections. Consequently, most of the seals that died during the seal plague epidemic died of pneumonia.
Howlers and sick seals on the beach
During the period when the young harbour seal suckles from its mother, a pup sometimes gets lost. The pup is in dire straights without its mother, and it climbs onto the beach and calls out for her. These young ‘howlers’, as they are known, cannot survive without their mothers and they are put down to prevent any unnecessary suffering.