Seals

Although there are 35 species of seals, only six types live in Antarctica: Antarctic Fur Seals, Crabeater Seals, Leopard Seals, Ross Seals, and Weddell Seals. However, these six species make up the majority of the world’s seal population. With no natural land predators, such as polar bears or man, Antarctic seals behave much differently than northern seals–showing little fear of man.

Seals are categorized into three families: true seals, eared seals (common to most zoos), and walruses (found in the arctic). All of the seals in Antarctica are true seals (no ears). Even without ears, seal hearing out of the water is as good as human’s. In the water, their hearing is even better. Its theorized that seals use a type of sonar to locate food, much like what dolphins and whales use.

In addition to using sonar for navigation and locating groups of food, its believed seals use their whiskers as a form of radar. The whiskers detect movement in the water and allow the seal to zoom in a particular object. Through the use of their sonar and radar, seals can actually find food in complete darkness better than in the light.

As for their eyes, seals don’t really see color but they are particularly sensitive to common sea water colors (greens, green-blues). Seals eyes have a silvery lining behind the retina, just like cats and other nocturnal/low-light hunters. This lining reflects the light back through the eye and increases the total amount of light absorbed by the eye–another necessary feature when hunting in the dimly lit depths of the oceans.

When in the water, a seal’s nose closes automatically and doesn’t reopen until it surface. Typically, a seal can remain underwater for 15 minutes (young) to 30 minutes (adults). This also is true of when they’re sleep. Seals sleep just under the surface of the ocean and can resurface for air without waking.


Antarctic Fur Seals

Unlike other seals found in Antarctica, Fur Seals are not true seals. They are from the eared seal family. They reside on the rocky shores of islands found in western Antarctica and average adults weigh 350 pounds (160 kilos).

Although extremely sociable among other Fur Seals, they are known to bit humans without provocation and move well enough to outrun humans on land. These poor manners were not helped by the fact that Fur Seals were heavily hunted during the 19th century. At one point, their total population was reduced to a few thousand.

Fur Seals were placed under protection at the beginning of this century and have made a remarkable recovery. Their breeding season begins in December and takes place in very large, dense colonies. At colonies on South Georgia Island, seal populations increase by an average of 17% a year. This translates to their population doubling every five years.


Crabeater Seals

crabeater.jpgDespite their name, Crabeaters eats mainly krill; crabs form only a small portion of the seals’ diet. Crabeaters live at the edge of pack ice and are normally solitary animals. However during the breeding season, they will form small family groups consisting of the mother, father and a pup.

The Crabeater seal accounts for over half of the world’s seal population. Estimates place the Crabeater’s population in excess of 30 million. Its population explosion is possibly due to the decline of whales, the Crabeater’s chief competition for krill.

The Crabeater’s main predator is the killer whale (or orca). Occasionally whales will bump an ice floe which has seals on it in order to knock seal into the water. Leopard Seals also prey on the Crabeater, although typically only on the young.


Leopard Seals

Leopard Seals are the largest of the true Antarctic seals. (Southern Elephant Seals are more common on islands near and above the Antarctic Convergence, although they do venture south to the actual continent.) Leopard Seals can grow to over 11 feet long (3.4 meters) and weigh, on average, 1,200 pounds (540 kilos). They are rather easy to identify due to the reptilian-like head, long sinewy neck, and arched thorax.

Although commonly found on pack ice, leopard seals spend a good deal of their time patrolling the shores of penguin rookeries. Warm-blooded animals account for nearly 40% of the leopard seals’ diet. Typically, they feed on penguins and small Crabeater seals. The remainder of their diet consists of krill (approximately 40%), fish, squid, and other invertebrates.


Ross Seals

Because of its tendency to live on heavy pack ice where ships cannot pass, little is known about this species. What is known is they’re nearly as large as Leopard Seals. Females Ross Seals can reach 11 feet in length (3.3 meters) and weight an average of 420 pounds (190 kilos). As with most Antarctic seals, males tend to be smaller.

Ross Seals are identified by the short heads and rather large eyes. Also, there often are strips starting at the chin and running along the sides of the neck to the chest. Their diet consists mainly of fish and squid, although they’re not opposed to eating other invertebrates.

Due to the lack of knowledge about them as well as their infrequent sightings, Ross Seals are protected under the Antarctic Treaty.


Southern Elephant Seals

These are the big daddies of the Antarctic beach. Elephant Seals can tip the scale at a hefty 7,900 pound (3,600 kilos) and measure up to 15 feet (4.5 meters). They commonly are found throughout the sub-Antarctic islands, although some colonies are located near the continent.

Being larger in this specie, males dominate the breeding process. They, first, battle with other males to establish territory on the beach. To the victor goes the spoils; this includes harems which can include up to 50 females. Breeding colonies are terribly cramped for space. These multi-ton beasts lie next to and on top of each other. Often, pups are crushed under the weight of adult seals.

In order to satisfy their huge appetites, Elephant Seals dive deep into the ocean and feed on various forms of fish and squid.


Weddell Seals

One of the more commonly sighted seals, Weddells often are found in groups. Some of these groups contain several hundred seals, although this typically occurs during their breeding season (September to November). During this time, males engage in numerous territorial battles.

Unlike other species, these seals prefer to lie on snow and ice even when open land or rock is available. This trait, along with their desire to avoid Orcas, is one of the primary reasons Weddells are found on inland fast ice around the continent.

During the winter months, Weddells must maintain diving/breathing holes in the ice in order to feed. Feeding primarily on fish, Weddells can dive in excess of 1,000 feet (300 meters) in search of food. To make these long dives possible, they carry five time the amount of oxygen in their blood as human do. To get the most from this, Weddells slow their heart rate and limit blood circulation to vital organs such as the brain, kidneys, and liver.

source: http://lrs.ed.uiuc.edu/students/downey/project/seals.html

 

Animals in land

Only a handful of tiny invertebrates, and not one single land vertebrate, can survive the Antarctic winter. The southern continent’s permanent inhabitant is a 12mm midge.

The terrestrial fauna of Antarctica consists entirely of invertebrates, mostly microscopic, which live in the soil and in vegetation. They rage from protozoa (single-celled creatures), rotifers, tardigrades and nematodes to arthropods (mainly mites and springtails). The largest invertebrate is the wingless midge (Belgica antarctica), which grows to 12 mm long.

Insects

Compared to other regions, insects are scarce and small in Antarctica. only 67 species have been recorded, and most are less than 2 mm long. Most of them are parasites, like lice which live in the feathers and fur of birds and seals, where they are protected from the harsh climate for much of the time. Collemola (springtails) are the only free-living insects. They feed on algae and fungi, and remain dormant in winter.

Mites

Mites, which belong to the spider family, are the commonest land animals. One of them, which is only 0.3 mm long, is the world’s most southerly indigenous animal. It has been found as far south as 85°. Many of the mites avoid freezing by a physical process known as “supercooling”, whereby their body fluids are maintained in a liquid state in temperatures below their normal freezing point. Species such as the oribatoud mite (Alaskozetes antarcitcus) and the springtail (cryptopygus antarcticus) have a constant struggle to maintain this unstable condition. The presence of food material in the gut provides some particles around which ice will form, so, in order to survive, they must strike a balance between freezing and starving. Their ability to synthesize glycerol, an antifreeze, enables them to survive temperatures of – 35°C.

 

source: http://library.thinkquest.org/26442/html/life/plant.html#

Plants

 The extreme conditions make Antarctica a habitat in which only the hardiest can survive. Very few species have been recorded on the 2% of the continent that is ice-free. They include about 150 lichens, 30 mosses, some fungi and one liverwort.

 

 

Few plants can tolerate the extreme cold, arid conditions of Antarctica. Some survive the frigid climate by colonizing in light-colored, semi-translucent rock These microscopic plants live just under the surface of the rocks where they are protected from drying out, extremely cold temperatures, and too much light. In the Dry Valley, some plants are dried out and inactive most of the time, but begin to grow for that short period of time when the water flows. The Antarctic Peninsula has a more maritime climate, getting both rain and snow. Plant life is a little more commonplace there. Below are pictures of the plants found in Antarctica along with some interesting facts.
Moss
Moss – on the better drained, stony slopes of the Antarctic Peninsula, mosses build up to a deep peat – as much as six and one half feet deep and 5,000 years old!
Lichen
Lichen – more than 350 species of lichens are known. They have proliferated in Antarctica because there is little competition from mosses or flowering plants which lack the high tolerance of draught and cold seen in the lichens.
Hairy Grass
Grass – also found on the Antarctic Peninsula. There are two species0 of flowering plants that grow on the peninsula – Antarctic hair grass and the Antarctic Pearlwort (on the right). They are the only two flowering plants, which grow south of 60° latitude.
 

Higher Plants

Only two native vascular plants, the Antarctic hair grass Deschampsia antarctica and a cushion-forming pearlwort, Colobanthus quitensis, survive south of 56°S. They occur in small clumps near the shore of the west coast of Antarctic Peninsula. This is in marked contrast to the Arctic regions where nearly 100 flowering plants are found at 84°N. Both plants can tolerate very cold and dry conditions. They continue to function at freezing point, when the rate at which they convert sunlight into chemical energy drops to about 30 to 40 per cent of that reached during the most favourable conditions.

Lichens

Lichen
          Of all the plants, lichens are best adapted to survive in the harsh polar climate. Some lichens have even been found only about 400 km from the South Pole. Lichens have proliferated in Antarctica mainly because there is little competition from mosses or flowering plants and because of their high tolerance of drought and cold. The peculiarity of lichens is that they are not one homogeneous organism but a symbiosis of two different partners, a fungus and an alga. The fungus part supplies the plant with water and nutritious salt, meanwhile the alga part organic substance, like carbohydrate produce. With this ideal “job-sharing”, lichens can survive the hardest conditions. Far from the border of highly developed plants, lichens are the pioneers of the vegetation.

Lichens aren’t only frugal and robust, they jug out because of their very low sensibility against frost. Some lichens, in an experiment, survived a bath in liquid nitrogen at minus 195 degrees.

On icy rock, lichens have the same strategy as plants have developed in the sand of the Sahara: they form an “oasis”. Like in the desert they miss water. They have only a chance to survive, if they settle in an area with a convenient, damp microclimate. Since what stops lichens to spread over the whole of Antarctica is not so much the big cold as the lack of water. For this reason they don’t settle in a place with the most sunshine, but in recesses and cracks between rocks. They like scanty soils, created by weathered rocks. They often quicken this process with secretion of acid.

Snowflake are captured in the cracked rock and smelt on the dark lichens, they can absorb the vitally liquid.

Especially unfavourable conditions are in the “dry valley” of East Antarctica, where big coldness and low snowfall meet. But even there scientists have found a dark cover on the north side of some rocks, which prove to be lichens. Under the microscope it was shown that the lichens penetrate the upper coat of the rock. With the dark colour the lichens absorb more light. This strategy enables the lichens to scrape a humble living in those quite high southern latitude.

An often seen lichen is Usnea sphacelata, which looks like a small forest of bonsai. They even grow on a height of some centimetres. They can only grow on about 120 day per year, so they only grow between 0.01 and 1 millimetre per year. But they live very long: an age of 200 years is not unusual, the record is about 4500 years.

Mosses

Only a small number of moss species are found in Antarctica. Extensive fields occur in a few places on this continent and these are rarely more than 100 mm deep, even in the most favourable areas where there is shelter and plenty of water. Short moss turf and cushion moss is found most frequently in sandy and gravelly soils. No extensive peat formations are to be found.

Mosses, like lichens, gather in colonies which make them possible to collect and retain more water. They also lose less by evaporation and show a marked ability to use water rapidly whenever it becomes available. Mosses have also become well adapted to the almost continuous light during the long days of a polar summer. One Antarctic moss, Bryum argenteum, produces more energy by photosynthesis in low light at 5°C than it does at 15°C, or higher. Photosynthesis can start within a few hours of thawing after a prolonged period of freezing, and almost immediately following short periods.

Algae

More than 300 species of non-marine algae have been found in Antarctica. These very simple plants take many diverse forms and a few have become adapted to living in difficult polar environments. Blue-green and other algae are found growing in damp sand and gravel around lakes and tarns, along meltwater streams or in low-lying areas, where snowdrifts or seepage may collect. Some such as Prasiola crispa can tolerate high levels of nutrients and are found near bird colonies. Others – the snow algae – may form extensive and spectacular red, yellow or green patches in areas of permanent snow. Recent studies have shown that some blue-green algae live inside rocks in dry valleys. Commonly they are found under stones, particularly light-coloured quartz stones, where the microclimate is more favourable than in the surrounding sand or soil. Together with lichens, they are the only living things in a barren landscape.

Fungi

Fungi have been studied little. Several mushrooms have been found on the west coast of the Antarctic Peninsula, and on the South Shetland Islands. A few of the fungi found in Antarctica are unique to the continent. The majority, however, are also found in most temperate areas

source: http://www.inchinapinch.com/hab_pgs/polar/antarctica/plants.htm

Animals in Antarctic ocean

 

Weddell Seal
Weddell Seal – the southernmost pinniped in the world. In what is known as reverse sexual dimorphism, males are generally smaller than females. A newborn pup has a coat of long hair, called lanugo, which they will shed within the first month as the protective layer of blubber is developed. Listen to a Weddell Seal underwater.
Orca Mom and Baby
Orcas – In the Antarctic, Killer whales live amid pack-ice, but they are said not to extend beyond the ice-line in the Arctic ocean. The Orca exhibits a great tolerance for varying temperatures. This is one of the reasons they enjoy a worldwide distribution.
Rockhopper Penguins
Rockhopper Penguins – one of the more ornate penguins, the Rockhopper stands 16- to 18 inches tall and weighs about 5 to 6 pounds. It can be found on subantarctic islands. Its population numbers appear to be stable at about 3.5 million pairs! These birds shake their heads and cause their yellow eyebrows to fly into a “halo” in order to attract a mate!
Black Browed Albatross
Black-browed Albatross – distinguished by its distinctive combination of white head and neat black brow. The Black-browed albatross can have a wigspan of up to eight feet and can weigh up to 10 pounds! Black-browed albatrosses are the most widely distributed of all albatross species. Of all the albatross species they may face the greatest threats from fisheries.
Leopard Seal
Listen to a Leopard seal.
Leopard Seal – named because of the colour patterns on its fur and its fierce nature, the Leopard seal is a fierce predator of it’s favorite food – Adelie penguins. They can leap up onto the ice and quickly grab a penguin. They also feed on fish, krill, and squid. Unlike other phocid seals, the leopard seal uses its large fore-flippers while swimming (sea lion style).
Blue Whale
Blue Whale – named for its blue-gray color, this huge cetacean may grow to be roughly 100 feet long and weigh more that 120 tons! A blue whale eats about 4 tons of krill per day during the feeding season! This means that about 40 million krill are eaten every day for six months by a blue whale! The tongue of the blue whale can be as big as a Volkswagen! The blue whale is the loudest animal on earth! Hear the blue whale.
Adelie Penguin
Listen to the Adelie
Adelie Penguin – the Adelies courtship ceremony begins when the male drops a pebble at the feet of his intended. They begin to fight, but if the female is interested, the fight is very short. Once the mates have been selected, the males commence gathering more pebbles for thier nests. Adelie penguins make their nests out of rocks! Ouch!
Antarctic Shag
Antarctic Shag – primarily eats fish, which they catch by diving. The bill of the Antarctic Shag is serrated for grabbing and holding onto slippery fish! All four toes on this member of the Phalacrocoridae family point forward – a rarity among birds!
Crabeater Seal
Listen to the Crabeater
Crabeater Seal – Crabeater seals are the most numerous pinniped species in the world and are curiously named since their major prey is not crabs but Antarctic krill! The seals have special lobed teeth that help them to sieve the krill out of the seawater. Crabeater seals have been known to dive as deep as 470 feet and for a period in excess of 10 minutes!
Wandering Albatross
Wandering Albatross – this species of albatross wanders the oceans for months at a time searching for food. It sleeps on the ocean surface at night and drinks seawater. The Wandering albatross is the largest bird in the world in terms of wing span – 11 feet! The Wandering albatross is endangered because of accidental killing of the bird on longlines.
Antarctic Fur Seal
Antarctic Fur Seal – tThe only eared seal in the Antarctic. Fur seals can be quite aggressive and it is wise to give them a wide berth, especially in the mating season! Within four years of their discovery in 1819, over 320,000 Fur seal pelts were taken from the South Shetland Islands. Today the Fur seals are making a rapid comeback and are regularly seen farther and farther south on the Antarctic Peninsula.
Emperor Penguin
Listen in on a
colony of Emperors!
Emperor Penguin – Emperor penguins, the biggest of the 17 penguin species, stand 3 to 4 feet tall and can weigh as much as 100 pounds! They are the only living species to reproduce during the harsh Antarctic winter. Without a nest, the male keeps the egg warm by holding it on his feet under an abdominal fold of skin for 2 months! Unbelievable! What a Dad!!
Elephant Seal
Southern Elephant Seal – largest of all pinnepeds. The elephant seal gets its name from the long, curved nose the male acquires around the age of three. The snout plays a significant role in the elephant seal’s spectacular breeding ritual. By a process known as a catastrophic molt, elephant seals shed their coats every autumn, sloughing large pieces of hair and skin, and leaving the seal with a ragged and tattered appearance until it grows new, sleek fur!
Chinstrap Penguin
Chinstrap Penguin – Chinstrap penguins are named for the narrow band of black feathers that extends from ear to ear. For nesting, they often select lofty sites that are the first to become snow-free, to ensure the maximum amount of time to raise their chicks. They are thought to be the most numerous penguin species with an estimated population of 12 to 13 million.
Ross Seal
Ross Seal – Ross Seals are very rarely seen because they live deep within the consolidated pack-ice. It is believed that Ross Seals feed mainly on squid and, to a lesser extent, fish and krill. They were named after the British polar explorer Sir James Ross, who first discovered them in 1840.

source: http://www.inchinapinch.com/hab_pgs/polar/antarctica/animals.htm

Penguins

Ice melting in Antarctica is also big problem for penguins.  Because of climate change, ice in Antarctica is melting and temperature of sea water is increasing.  These problems limit to supply food in the sea.  Ice melting also cause penguin colonies to head farther south.

Check out what we can do: http://www.asoc.org/issues-and-advocacy/antarctic-wildlife-conservation/penguins

Enhanced by Zemanta

Related Blog about This Issue

We have found a great blog which displays wonderful articles about Antarctica. Please check it out if you are interested in.

http://itscold.edublogs.org/level-one/

Map of Antarctica

 

This map will help us to imagine where is the exact location of Antarctica.

Map of Antarctica

Hidden Chasm hastens Antarctic melt

Hidden Grand Canyon-sized ICE-HOLE hastens Antarctic melt

This page tells us about the currently happening phenomenon in Antarctica, what makes the ice is melting faster these days. In addition, it consists a video to help the viewers understand the problem clearly.

Follow

Get every new post delivered to your Inbox.

Join 2,741 other followers