Adelie PenguinOne of the most common and well-known of all Antarctic penguin species, Adelie penguins can be found forming colonies on islands, beaches and headlands all around the Antarctic coast. Niche. has thrilled Antarctic visitors for generations. Early explorers made use of the ubiquitous Adelie not only for endless entertainment but also as a source of eggs and tough, but tasty meat. Scientists today use the Adelie as an indicator species to monitor the abundance of krill, so important to the web of Antarctic life. The Adelie penguin is the stereotypical penguin. With its white 'tuxedo shirt' front, and the white ring around its eyes, the bird has a handsome, yet comical appearance. Its beak is reddish with a black tip. Adelies vacate their winter quarters on the comparative warm Antarctic ice pack and arrive at the rookeries during September and October, often scampering several miles over the sea ice to reach their ancestral coastal homes. They typically establish dense colonies on the ice-free slopes of rocky coasts, headlands and islands. Competition for nesting sites can be fierce and the older more dominant birds tend to stake nests in the middle of the colony where they are better protected from marauding skuas. Behavioral. A mating pair of Adelies will build a rocky nest of small stones carried in the birds' beaks and dropped into place. Two greenish-white eggs are usually laid in early November. Males and females take turns incubating the eggs, however, the female returns to the sea first, often leaving the male to stand alone for up to ten days while she feeds Physiological. Hatching occurs after about 35 days. The chicks are brooded closely by their parents for the first two to three weeks. While the two chicks hatch almost simultaneously, inevitably one chick is stronger and is better able to win food, which is regurgitated from the crop of whichever parent is present at the time. Growing rapidly, the chicks soon develop a thick woolly gray down and quickly become almost as large as their parents. During the third or fourth week they huddle with other chicks in nursery groups called 'crèches' for both protection and warmth. This leaves the parents free to go to sea on feeding forays in order to satisfy their chicks' increasing appetites. Often, a parade of adults can regularly be seen moving between the colony and the sea on such feeding trips. By late March most of the chicks can swim and the Adelies then depart for the pack ice and the sea. The Adelie's main oceanic predators are leopard seals which often lie in wait beneath the ledges to snare the first penguin into the water.
Orca/Killer WhaleOrca or Killer whales are the largest members of the dolphin family. Found in all waters, these splendid, toothed whales are sometimes called the 'wolves of the sea' because of their closely-related pack-like behaviors. Gracing the southern seas in abundance, Orcas tend to travel in small close-knit, family pods but can be found in groups of up to 50 individuals. Behehavioral Orcas have not been caught commercially since the early 1980's as a result of protective measures imposed by the International Whaling Commission (IWC). However, Orcas are still captured in small numbers for display at zoos and marine parks. This is an emotional and controversial issue to be sure, but not one of conservation significance as Orca populations are currently thought to be stable. Probably Orca whales are excellent swimmers and can perform impressive acrobatics in the water. They can often be observed breaching, a behavior in which the whale speeds to the surface and leaps completely out of the water, falling back with a spectacular splash. Or they may be seen 'spyhopping'--poking their heads straight out of the water to get a better look at their surroundings. 'Tail slapping' is another common activity possibly meant as a kind of warning to other members in pod. Orcas are very efficient and sophisticated predators who often hunt in groups, attacking prey much as wolves attack larger caribou or moose, then sharing the spoils. They eat fish, squid, sharks, birds (including penguins), seals, sea turtles, octopi, and other whales. An Orca will tip up small ice floes to dislodge resting seals while other Orcas wait beneath the surface for the kill. They have even been observed attacking young, but still huge, Blue whales. Aside from human beings, Orcas have no natural enemies. They can dive to depths of up to 100 feet in pursuit of prey but prefer to hunt at or near the surface of the water. Orcas are very social animals. The bonds between pod members are strong and last for life. Orcas share the responsibility of protecting young, and caring for the sick or injured. Orca breeding occurs mostly in the winter to early spring. The gestation period is about 16-17 months. Newborn Orca calves instinctively swim to the surface within ten seconds for their first breath, helped along by mother's flippers. Calves are about seven feet long and weigh up to 400 pounds at birth. The mother and calf may stay together for a year or longer. Female orcas reach maturity at 6-10 years old, and males at 12-16 years old. Fur Seal Antarctic Fur seals are found mainly on the sub-antarctic islands of South Georgia, South Shetland, South Orkney, and South Sandwich, though today they are regularly seen farther and farther south on the Antarctic Peninsula. These charismatic marine mammals have made a remarkable comeback. Killed throughout the 1800's for their dense short fibered fur that was made into ladies coats, sightings of Antarctic Fur seals in the early 1900's were extremely rare. However, with the rise of whaling and the ensuing superabundance of krill, Fur seal numbers have rebounded dramatically with some localities even experiencing problems of overpopulation. Members of the group known as the Otarid or "eared" seals, Fur seals have a visible earflap. In facial appearance and manner they resemble large dogs. The males can reach 450 pounds and can be up to four times larger than the females. Adult males are silvery-gray with a thick mane and longer hair. Females are gray to brownish with creamy throats and chests. Antarctic Fur seals occur farther south than their slightly smaller relatives, the sub-Antarctic Fur seal (Arctocephalus tropicalis), with which it sometimes hybridizes. About 1 in 800 Fur seals are of the 'blonde' variety, with markedly yellow or cream-colored fur. Fur seals on South Georgia feed mainly on krill while at Heard Island and at Macquarie Island, located north of the Antarctic Convergence, they feed mainly on fish, and some squid. In pursuit of prey, Fur seals usually dive to around 100 feet but can exceed 300 feet and remain submerged for up to five minutes. On land, they are able to bring their rear flippers under their body taking the bulk of their weight on their fore-flippers. This allows them much more agility and speed on land compared to Southern Elephant, Weddell and Crabeater seals. Fur seals breed in male-dominated groups or 'harems', and males can be fiercely aggressive toward rivals and human intruders alike. Establishing territories through fighting with other males, dominant bulls will patrol a portion of a beach from the waters edge to the vegetation behind. They spend inordinate amounts of energy discouraging females from leaving their territory and fending off other males. Territorial bulls give off a strong sweet musk odor during the breeding season. Pups are born from late November to early January, weighing between 6 and 15 pounds at birth. They are weaned after four months. Today Fur seals face threats from habitat loss, overfishing, oil spills and entanglement in fishing nets. Antarctic Site