Migratory seabirds and marine mammals are found in tremendous numbers around the coastal areas of Antarctica from late October to early March. This abundance coincides with continual daylight. These are the months when Antarctic wildlife expeditions are possible.
Considering the harsh climate and the poor soils, it makes sense that Antarctica has so few species of plants and animals: 360 species of algae, 400 species of lichens, 75 species of mosses and no ferns. Two species of flowering plants occur in the warmer maritime region of the Antarctic Peninsula: the Antarctic hair-grass (Deschampsia antarctica) and the Antarctic pearlwort (Colobanthus quitensis). All Antarctic plants grow slowly, and only a few species grow taller than 3 cm (1.25 inches).
The most obvious animals in Antarctica are birds. Only 43 species of birds breed south of the Antarctic Convergence, nearly all of them seabirds. Many ornithologists believe that Wilson's Storm-petrel, which breeds by the millions in Antarctica, may be the most numerous species of bird in the world.
Penguins and Antarctica are synonymous. Surprisingly, of the 17 species found in the southern hemisphere, most of them live north of the Antarctic Convergence, the biological boundary that separates Antarctica from the rest of the world. Only the Emperor and Adelie Penguins are restricted to Antarctic habitats. Gentoo, Chinstrap, King, Macaroni, Rockhopper, and Magellanic Penguins may be encountered in Antarctica or on subantarctic islands.
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Emperor Penguin chick calling for food.
Antarctic Land Mammals
In Antarctica, land animals must endure tremendous variations in temperature, whereas aquatic animals living in the ocean are in a more uniform environment. To survive freezing, an insect must prevent ice from forming inside its cells, and at the same time induce ice formation slowly within the rest of its body, including the contents of its gut, the blood and spaces between the cells.
The only terrestrial herbivores to be found are tiny insects and mites that feed mainly on algae, fungi, and rotting plant material. The only terrestrial carnivores are tiny mites which feed on the herbivorous mites and insects. Besides mites, the invertebrate fauna includes two midges, springtails, rotifers, tardigrades and nematodes. Parasitic species, such as ticks, and mites, and internal parasites, occur on birds and seals.
Antarctic Marine Mammals
Animal life abounds in the seas surrounding the Antarctic continent for three reasons:
- Sea water is cold.
- Storm-tossed seas with their up-wellings and strong currents keep essential nutrients in suspension where they can be easily used by the immense growths of phytoplankton.
- Long hours of daylight during the summer months promote almost continuous photosynthesis, which encourages algal blooms that form the underlying basis of the Antarctic food chain.
The marine mammals of Antarctica are able to maintain an optimal internal temperature regardless of the cold. Living at the optimum temperature means that their life processes, such as nerve tissue transmission, muscle contraction, digestion, etc., operate at efficient rates but at a high metabolic cost.
Seals: Are a group of marine mammals called pinnipeds. Pinnipeds have an enormous amount of blood in relation to their body size (about twice the amount found in a comparably sized human). The southern elephant seal has a large circumpolar range which includes most of the subantarctic islands as well as a few continental coasts. It is the largest species of seal in the world, surpassing the walrus in size. The Weddell seal is the most southerly seal and indeed the most southerly of all mammals breeding as far south as 78°S. Crabeater seals are the most abundant seal in the world. Despite its name, the crabeater lives almost entirely on krill. The leopard seal is a predator, the only Antarctic seal to regularly consume warm-blooded prey.
Whales: Antarctic baleen whales have a distinct annual cycle of breeding in the warm waters at low altitudes in winter, and feeding in the cold Antarctic waters in the austral summer. The southern right whale was greatly over-exploited by whalers, almost disappearing by the end of the 19th century. Now totally protected, the southern right whale is making a gradual recovery. The humpback whale is the easiest great whale to identify. Humpbacks often leap completely out of the water to land on their backs with a tremendous splash. Besides breaching, the humpback whale waves and slaps its enormous flippers on the surface of the water to make a loud sound rather like a gun shot. This species is amazingly acrobatic and energetic and never fails to create excitement among visitors lucky enough to encounter one.
Quark stops for whales. When one of our vessels encounters a pod of whales – as long as the conditions are safe for both human and whales – the Expedition Leader will call for Zodiacs to be lowered. An announcement will be made instructing our guests to don their parkas and waterproof pants to board the inflatable landing crafts. We stop for whales!