Penguin: Habitat, Characteristics, and Special Features
Penguin, of the order Sphenisciformes, comprises 18 different species. These species consist of marine birds which are flightless and inhabit the Southern Hemisphere only. We often wonder about “what is a penguin’s habitat?”. The majority of these 18 species do not live in only Antarctica, but penguin habitat is the regions between latitudes 45° and 60° S. They breed on the islands. A few of the penguin habitat is in the temperate regions. And, one of the species, the Galapagos penguin, with the scientific name Spheniscus mendiculus, lives at the Equator.
General Penguin Features
Penguin animal is endeared by people worldwide because of its stocky, short-legged appearance. Among other penguin characteristics, their height ranges from around 14inches or 35cms and weight ranges from approximately 2pounds or 1kg in the fairy, or the blue penguin, the Eudyptula minor to 45inches or 115cms and 55 to 90pounds or 25 to 40kgs in the emperor penguin, the Aptenodytes forsteri. One of the significant penguin features is its colour. Most of the penguins are black in colour on their backs and white underneath. Often lines of black runs across their upper breasts and have white spots on the head. Very rarely they have colour. It is limited to yellow or red irises in certain species. Few of them sport red feet or beaks. Three species of Eudyptes have yellow brown tufts. The emperor and king penguins have yellow and orange on the breast, neck, and head.
The total population of the emperor penguin and some other species is estimated to be in the hundreds of thousands. But most of the other species of smaller penguins are in millions. Massive breeding colonies on islands, some of which swarm with hundreds of thousands of nesting pairs, amount to an enormous potential resource for food, but the economic significance of the penguin animal is negligible. The seal hunters and the whalers from the nineteenth century visited some of the colonies for eggs and meat. A penguin-oil industry had once taken a large population of these birds. However, by the beginning of the 20th century, that exploitation was not profitable anymore. Most of the colonies were left alone. Some of the colonies were actively protected too. As a result of the decimation of the Antarctic whales in the mid 20th century apparently, some of the penguin species are now growing in numbers. The Antarctic whales and these penguins used to feed on the same minute crustaceans, or the krill. The populations of penguins are highly vulnerable to climate changes and the ocean-temperature changes, including the changes due to global warming. The depletion of the populations of local fish by humans too affects the penguin animal.
Natural History of the Penguin Vertebrate Group
A lot of features of penguin life cycle differ with the size of the body and the geographic distribution- the chronology of breeding also might differ within a species according to the latitude. Most of the species breed only once every year. Few of the species also breed twice in a year, e.g., the blue penguin and the African penguin or Spheniscus demersus and probably some other members of this genus. The king penguin breeds two times in three years. The king and the emperor penguins lay one egg and all of the others lay two or sometimes three eggs. The southern spring or summer is the beginning of the breeding season for most penguins. King penguins have a cycle of 14 to 18 months. The duration of a particular pair depends on the failure or success of the last attempt at breeding. For some of the gentoo penguin or Pygoscelis papua populations winter is the breeding season. Autumn marks the beginning of breeding for the emperor penguin, apparently timed in a way so that after the long developmental duration the young is produced in midsummer, when the chances of survival are greatest for them.
The gentoo, with a circumpolar distribution, is noteworthy as it lacks synchrony amongst populations. But its breeding routine is actually comparable to that of the majority of the other species. Laying of eggs takes place in July in the Crozet islands of southern Africa. The incubation period of the two eggs is 35 or 36 days, and it takes two months to rear the chicks. In January the last of the immature birds go to the sea.
Between the arrival and the departure of the birds at their colonies, different kinds of vocal and visual displays are employed. During pairing and to a lesser extent during the succeeding phases of breeding courtship calls are used. The vocal differences between sexes in the king penguin and the emperor penguin are well marked. In some of the other species the dimorphisms are less-marked. Upon arriving at the colony every bird generally rejoins its mate from the previous year by returning to the nest it left the previous year. Only the death of its mate compels it to find another partner. Even the emperor penguin follows the same being fully capable to find its mate despite the absence of a nest and the vast size of the colony.
The displays occurring due to the reassembly of the colony and the mate-finding, as well as the ones preceding copulation, are more or less similar amongst most of the species. But the vocalisations that accompany are more diverse. Trumpeting, croaking, cackling, and cooing are some of the sounds associated with the various species. Members of the genus Spheniscus make braying sounds and so are called jackass penguins. The behaviour of the younger birds is less elaborate and less effective than that of the older experienced birds. Adélie penguins or, Pygoscelis adeliae, as an example, return to the reproductive colony from their third year onward but until their fifth-sixth year they do not breed successfully.
In all species except for the emperor penguin, incubation of eggs is performed by both the sexes. In emperor penguin, the incubation is done exclusively by the male and it is started immediately after the laying of eggs. The bustling and myriad cries that represent mating are followed by inactivity and quiet, once the incubation phase sets in. The inexperienced birds show faulty incubation behaviour and as a result the eggs break or stay abandoned. The mortality rate of both the eggs and chicks is significant at the egg-stage. It varies from one year to another depending on the percentage of young birds in the reproductive population, climatic conditions, and the pressure of predation. Generally the mortality of both eggs and chicks is around 40 to 80 percent of the total number of eggs laid. The predators in the coastal colonies are skuas, sheathbills, and the giant petrel- in the order of importance. Certain penguins, in the Australian, African and South American continents, nesting in burrows and being nocturnal, are substantially protected from predation, which is majorly by man and gulls.
After laying eggs, the females depart for the sea to feed, and return after 10-20 days to relieve her mate. The father and the mother alternate in durations of a week or two thereafter. However, the female emperor penguin often walks 50 to 100miles or 80 to 160kms from the colony to the sea and returns after the end of the duration of incubation. During the 64-day duration of the incubation period that extends through the apex of the Antarctic winter, the egg is incubated by the male emperor penguin. It holds the egg on his feet and lives on stored reserves of fat. Members of the colony come together for mutual protection from wind and cold during violent storms in winter, and gather in tightly packed crowds called huddles.
Locomotion and Orientation
One of most penguin special features is their adaptability for fast movement in water. During locomotion their wings or flippers are used for propulsion. These birds literally fly underwater. While moving with very high speed, they leave the water frequently in leaps, which carry them a meter or longer through the air. It’s during this time they breathe.
On land, the movement of these birds is much more awkward. It even seems amusing since they rock from one side to the other as they walk. Penguins can however run at surprising speeds, despite their short legs. Some, like the Adélie penguins, the southern rockhopper or E. chrysocome, and northern rockhopper or Eudyptes moseleyi use flippers for balance and move within rocks with agility. Many penguins toboggan on snow or ice, by sliding on their bellies as they propel themselves with their flippers and feet. The flippers and the beak act as the prime defense and attacking weapons.
The species, the time of year, and the geographic region dictates the type of food utilized. Krill, which attains high densities in the rich, well-oxygenated Antarctic waters, is the primary food for most of the smaller penguins from the south. Fish is the basic element in the diet of the African penguin. Cephalopods like cuttlefish and squid, and the small fishes form substantial fractions of the food for the majority of the penguin populations. The total weight of food consumed by a large colony of penguins often exceeds several tons per day.
Penguin Special Features
The penguins have a flightless aquatic existence and so are highly specialised. The bird is able to carry itself upright because the feet are located much farther back than those of other birds. In other birds the sole comprises the toes only, but in penguins it’s the whole foot. The most noteworthy penguin characteristic is the transforming forelimb to paddle and back to forelimb. The penguin details entail its thoracic cage which is developed well, and the sternum bears a strong keel to which the pectoral muscles are attached to move the flippers. The skeletal base of the flipper is the same as the wing of flying birds, but here the elements are flattened and shortened which produces a relatively rigid limb covered with very short feathers, which is an ideal organ for quick thrust. The plumage of the body too consists of very short feathers to minimize turbulence and friction. The plumage density and the layer of air it retains provide almost total insulation to the body.
Paleontological evidence, consisting of well-defined fossils dating back to about 50 million years, points out that the order Procellariiformes comprising petrels, albatrosses and shearwaters, and the penguins had a common origin. Numerous distinctive branches, recognisably all penguins- some even giant in size, were produced by the flightless sphenisciformes line. Every fossil remains of penguins found is collected from within the zone of distribution of Sphenisciformes of present day. Some of them apparently lived in warmer regions than the ones penguins live in today.