ELEPHANT SEAL, SEA LEOPARD

Press, Volume CXIV, Issue 33675, 26 October 1974, Page 11

ELEPHANT SEAL, SEA LEOPARD

The elephant seal and the leopard seal belong to the phocids or earless seals and have their hind flippers permanently directed backwards: consequently they move on land in a hitching or looping type of motion. The southern elephant seal (Mirounga Leonina) is the largest of the earless seals, the females reaching a length of 12ft and the males measuring 21ft and a weight of more than three tons. The males are dark brown or dark grey in colour, lighter below; the

most prominent feature of the male is the inflatable proboscis. This is not fully developed until the animal is about eight years of age and fully matured sexually. It is inflated by' muscular action and blood pressure. The females do not possess this characteristic proboscis of the male. The ear, situated behind and below the eye, is no more than a hole in the head; there is no external ear-flap. The body is thick-

set and muscular, and has no obvious neck. The fore-flippers are strong and sturdy, with the fingers joined together to form a fin. The coat consists of short stiff hairs and varies from grey-blue

to white on the underside and flanks, according to sex and age. The pups are born after 340 days gestation and mating takes place soon after the birth of the pups. > The very short interval between the birth of the pup and the mating of the mother is possible — aS in other seals — because the uterus has two horns that function alternately. One is always ready to function after mating while the other is recovering from birth activity. The pups at birth weigh from 901 b to' 1101 b and are about 4ft long. They have

a black fluffy coat; within two weeks they moult this for a grey one. The suckling period lasts for about five weeks. At the age of three to four months the youngster can swim perfectly and is completely at home in the water. The males do not develop their trunk before three years old. The average life span is about 30 years. During September the females reach their breeding stations, and form groups of about 20, and a week or so later the cows give birth to their single pup. The bulls do not form their harems until the pups are arriving, and during this time battles between males are accompanied by much roaring but little actual fighting. Defeated bulls are not allowed to form haremsand are relegated., to join the outcasts around the edge of the colony. The harem territories are closely spaced and the bulls are very much occupied guarding the boundaries of their territory, mating with and supervising the members of their harem. The virgin cows, or those not in calf arrive after all the harems have been set up. These cows mate with bulls that have not been able to form a harem. Towards the end of November the harem system* breaks up and all the elephant seals return to the sea. Towards the end of January all return to land to moult, but this time the

cows and bulls form separate colonies. After moulting they return to the _sea and remain there until the next breeding season. Leopard seal The leopard seal (Hydruga Leptonyx) ranges widely through the southern oceans from the Antarctic shore ice to the southern coast of inhabited regions of the Southern Hemisphere. Both immature and adult seals migrate northwards in the autumn and winter,

and some may reach the coasts of New Zealand. They are solitary ani- * mals for most of the year. Large colonies have, however, been reported from the Falkland Islands and on Heard Island. Little is known about the breeding habits of the leopard seal, but it is thought that pups are born between September and January. Females are believed to attain maturity about 2A n years old and give birth to their first pup in their third or fourth year. Males evidently do not reach maturity until their fourth year. They are apparently migratory and the younger animals wander further afield than the adults.

Most specimens that reach New Zealand waters are immature and are usually exhausted, hauling out on the coasts of the South Island as far north as Cook Strait. They are carnivorous, feeding on cuttlefish, penguins and sea birds generally and are very active in the water, diving and turning quickly in order to catch their prey. It is the only seal in which the adult females are larger than the males. The females grow to about 12ft with a maximum weight of 10001 b. The males later grow to about 10ft and a weight of about 6001 b. The pups at birth are about sft and probably weigh about 601 b. They are suckled for about two months. About two months after giving birth the females

Seals which have been represented on stamps include: Southern elephant. — Austr. Ant Territory, 1969, 9c; Fr. S. Ant. Territory, 1956, lOf, 15f, and 1963, 8f (Fighting males); South Georgia, 1963, sjp, and ssh (with Fur Seal), 1971, ljp, slp, and 25p; Tristan da Cunha, 1954, 2sh. Leopard. — Fr. Southern and Ant. Territory, 1959, 4f; South Georgia, 1963, Ish, and 1971, 7Jp.