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Monday 28 February 2011

Penguins diet and eating habits

DIET & EATING HABITS

FOOD PREFERENCES & RESOURCES
1.Penguins eat krill (a shrimp-like crustacean in the Family Euphausiidae), squids, and fishes. Various species of penguins have slightly different food preferences, which reduce competition among species. See species appendix for the diet of each species.
  
2.The smaller penguin species of the Antarctic and the subantarctic primarily feed on krill and squids. Species found farther north tend to eat fishes.
  
3.Adélie penguins feed primarily on small krill, while chinstraps forage for large krill.
  
4.Emperor and king penguins mainly eat fishes and squids.

 
FOOD INTAKE
1.Intake varies with the quantity and variety of food available from different areas at different times of the year.
  
2.A colony of 5 million Adélie penguins may eat nearly 8 million kg (17.6 million lb.) of krill and small fishes daily.

 
METHOD OF COLLECTING AND EATING FOOD
1.Penguins feed at sea. Most feeding occurs within 15.3 to 18.3 m (50-60 ft.) of the surface. The location of prey can vary seasonally and even daily.
 
 
Penguins rely on the ocean for food.  And although they are well studied on land, penguin behavior at se is relatively unknown.
Penguins rely on the ocean for food. And although they are well studied on land, penguin behavior at sea is relatively unknown.
 
2.Penguins primarily rely on their vision while hunting. It is not known how penguins locate prey in the darkness, at night, or at great depths, Some scientists hypothesize that penguins are helped by thebioluminescence (light producing) capabilities of many oceanic squids, crustaceans, and fishes.
  
3.Penguins catch prey with their bills and swallow it whole while swimming. A penguin has a spiny tongue and powerful jaws to grip slippery prey.
  
4.Different species travel various distances from the colony in search of food.
Hunting areas may range from 15 km (9 mi.) from the colony for Adélies to nearly 900 km (559 mi.) from the colony for king penguins. Emperor penguins may cover 164 to 1,454 km (102- 903 mi.) in a single foraging trip.
Penguins walk and toboggan from feeding grounds to rookeries. When fishing grounds are far away, penguins will feed in seal holes and other openings in the ice.

 
FASTING
1.Penguins go through annual fasting periods. Prior to fasting, penguins build up a fat layer, which provides energy.
Penguins fast for prolonged periods during breeding seasons; they do not leave nesting areas to feed. Some penguins fast throughout the entire courtship, nesting, and incubation periods.
Penguins also fast during annual molting periods. The temporary reduction in insulation and waterproofing caused by the loss of feathers during a molt prohibits penguins from entering the water to feed. Their fat layer provides energy until the molt is over.
 
 
Penguins fast during annual molting periods.
Penguins fast during annual molting periods.
 
Chicks fast near the time they are ready to shed juvenile feathers for adult plumage. Usually by this time, the parents no longer are feeding the chick. Growth stops during this fasting period, but resumes once the molt is complete.
  
2.The length of fasting depends on penguin species, sex, and type of fasting. The king and emperor penguins have the longest fasting periods.
Breeding male king penguins may fast for up to 54 days during courtship and the first incubation shift.
Breeding male emperor penguins may fast 90 to 120 days during courtship, breeding, and the entire incubation period.

COMMUNICATION
VOCALIZATION
1.Penguin calls (vocalizations) are individually identifiable, allowing mates to recognize each other and also their chick. This is important because members of a large colony of penguins are nearly indistinguishable by sight.
  
 
Penguin VocalizationPenguin Vocalization

  
2.Research has identified differences in the calls of male and female emperor penguins. These differences probably function in courtship and mate selection.
  
3.There are three main kinds of penguin calls.
The contact call assists in recognition of colony members. The contact call of emperor and king penguins can be heard one kilometer (0.6 mi.) away.
The display call is the most complex of all the calls and is used between partners in a colony. The call must convey information on territorial, sexual, and individual recognition.
The threat call is the simplest and is used to defend a territory and warn other colony members of predators.
 
 
The threat call is used to defend a territory.
The threat call is used to defend a territory.
 

 
DISPLAYS
1.Penguins communicate by vocalizing and performing physical behaviors called displays. They use many vocal and visual displays to communicate nesting territories, mating information, nest relief rituals, partner and chick recognition, and defense against intruders.
 
 
Penguins perform physical behaviors called displays to communicate.
Penguins perform physical behaviors called displays to communicate.
 

Penguins Senses

SENSES

HEARING
1.As in most birds, penguin hearing is probably good, but not as acute as that of marine mammals. The hearing range for most birds is 0.1-8 kHz. Hearing for penguins has not been well researched, but vocalization has. Vocalizations (calls) are important in communication and mate recognition.

 
EYESIGHT
1.A penguin's eyes are adapted to see clearly both in air and under water. (Howland and Sivak, 1984)
 
 
Penguins can see well in the air and under water.
Penguins can see well in the air and under water.
 
2.Penguins have color vision and are sensitive to violet, blue, and green wavelengths of light.

 
TASTE
1.The sense of taste in penguins has not been extensively studied. In general, the sense of taste is poorly developed in birds.

 
SMELL
1.A penguin's sense of smell may be more developed than early studies indicated. The olfactory lobe of a penguin's brain is large. Studies on captive Humboldt penguins indicate that this species may have some sense of smell.
 
 
Studies conducted with Humboldt penguins indicate they may have a sense of smell.
Studies conducted with Humboldt penguins indicate they may have a sense of smell.
 

Penguins behaviour

SOCIAL BEHAVIOR
1.Penguins are among the most social of all birds. All species are colonial.
Penguins usually associate in small groups while at sea, but often gather by the thousands when nesting on land.
Penguins are among the most social of all birds.
2.Penguins may swim and feed in groups, but some may be solitary when diving for food. Emperor penguins have been observed feeding in groups with coordinated diving.
3.During the breeding season penguins come ashore and nest in huge colonies called rookeries. Some rookeries include hundreds of thousands of penguins and cover hundreds of square kilometers.
While on land, some penguins gather in the thousands, like the Adélie penguin colony on Paulet Island off the tip of the Antarctic Peninsula.
While on land, some penguins gather in the thousands, like the Adélie penguin colony on Paulet Island off the tip of the Antarctic Peninsula.
4.Penguins exhibit intricate courting and mate-recognition behavior. Elaborate visual and vocal displays help establish and maintain nesting territories.
5.Although king penguins are highly gregarious at rookery sites, they usually travel in small groups of 5 to 20 individuals.
6.Penguins communicate by vocalizing and performing physical behaviors called "displays". They use many vocal and visual displays to communicate nesting territories and mating information. They also use displays in partner and chick recognition, and in defense against intruders.
Male penguins perform ecstatic displays to establish possession of nesting sites, attract females, and warn other males to stay away.
Male penguins perform ecstatic displays to establish possession of nesting sites, attract females, and warn other males to stay away.


INDIVIDUAL BEHAVIOR
1.Navigation.
Studies of Adélie penguins indicate that they use the sun to navigate from land to sea. They adjust for the sun's changing position in the sky throughout the day.
2.Preening.
Penguins preen their feathers frequently. Feathers must be maintained in prime condition to ensure waterproofing and insulation.
Penguins preen with their bills. A gland near the base of the tail secretes oil that the penguin distributes throughout its feathers.
Penguins preen for several minutes in the water by rubbing their bodies with their flippers while twisting and turning.

Wednesday 23 February 2011

Penguin's Habitat

Everything you ever wanted to know about a penguin’s habitat





A penguin’s habitat is naturally cold and watery.  All varieties of the penguin are native to the southern hemisphere, and in fact, they can be found on every continent in the southern hemisphere.  Penguins are especially abundant on islands in colder climates, and they tend to remain in areas that are isolated and free of most predators. 



In all, there are 17 different species of penguin in the world, and not all of them live in cold climates like we imagine.  The majority of penguin species do prefer colder climates, although there are even some penguins that are native to some of the tropical climates located right at the equator.  The penguin’s habitat can range from a sheet of ice to warm, sandy beaches, depending on what kind of penguin it is. 



However, one thing that is constant across all types of penguins is the need for a body of water nearby.  The penguin cannot fly, so the penguin’s habitat consists of plenty of water for them to swim in.  Penguins spend about 75 percent of their lives in the water, and they favor cold currents that bring plenty of food right to them.  Penguins need a body of water to hunt for food.  They eat fish, squid, and various types of crustaceans.   The body of the penguin is also designed specifically for the water, giving them a streamlined body shape and feathers to help them move easily through the water and keep their body temperature regulated, even in the coldest water of Antarctica. 


The penguin’s habitat also changes depending on what time of year it is.  Penguins migrate from the breeding grounds to feeding areas along the coast.  Some types of penguins travel very far during their migrations, while others travel only a short way.  The penguin also likes to explore, especially while it’s young.  It’s not uncommon for young penguins to leave home and wander around the area to check it out, although they typically do return home to molt and breed.  Penguins also tend to build nests, using rocks, sticks, or whatever they can find to build homes.  They used these nests to lay their eggs and care for their babies.

The penguin’s habitat is still changing today, just as it has for the past 100 years.  Researchers believe global warming is affecting penguins and threatening their habitats.  Warmer climates in colder areas mean less ice for them to live on.  Warmer climates also make it more difficult for some types of penguins to survive.  It increases the number of penguins that die because of the heat.  More sun makes it more difficult for cold air penguins to regulate their body temperatures.  All that heat may also keep the penguins from reproducing, which further decreases their numbers. 

Another interesting thing about penguins is that they mate for life.  Unfortunately, this can mean that if one half of a pair leaves for too long to look for food, then the other penguin abandons the eggs to look for food.  This decreases their numbers even further.

Tuesday 22 February 2011

Penguin Species and Taxonomy

     There are quite a few distinct species of penguins out there. Unfortunately they often get lumped together with a general term. However, once you start to explore their appearance, where they live, and their behaviors you will understand that there are quite a few differences from one to the next.
There is some debate out there when it comes to the various species of penguins. Many experts will tell you that there are only 17 of them. Others believe that there are 18 of them. The one that is highly debated is the Fairy Penguin with the characteristic of white flippers. Others believe that this is a mutated change though for survival and not a separate species.

Popular Species


     One that is very popular is the Adelie Penguin. It is the smallest of them found in the Antarctic. Adelie Penguins have a head that is completely black except for a white circle around their eyes. They are only about 2 feet tall and weigh less than 10 pounds. They are very aggressive in nature to each other. They form colonies of up to 10,000 of them in one location.

     The King Penguin is said to be the most beautiful due to the coloring of both yellow and orange on them. They are the second largest of the birds and can be up to 3 feet tall and around 35 pounds. The Gentoo Penguin is about the same height but they weigh less than 15 pounds so they are tall and slender. They have a strip of white that looks like an upside down horseshoe from the top of each eye and across the back side of the head.


Emperor Penguins

The largest of all penguins is known as the Emperor Penguin. The males and females are hard to distinguish as they are very similar is physical size. Adult Emperor Penguins can weigh up to 85 pounds and be up to 48 inches tall. They back parts of the Emperor Penguins are black with a white front. They also feature bright splashes of yellow and orange on their breast region and their ears. The only place you will find the Emperor Penguin is in Antarctica. A great deal of research has been conducted to find out how they are able to survive in such harsh conditions. What we have found out is that they are able to manipulate their bodies in order to adapt to the environment. They can be completely functional at levels with low oxygen, they have solid bones, they can slow down their metabolism when necessary, and even shut down all non-essential bodily functions for a period of time.







Adelie Penguins

The Adelie Penguin is one that often looks quite overweight. It is short but wide which tends to give it that appearance. They are very short with an overall height of no more than 30 inches. They weight approximately 15 pounds. Classified as the smallest of the Antarctic penguins though it is definitely able to hold its own out there. They have some identifying marks that help to keep them properly identified. You will notice they have rings of white around their eyes and the end of their bill. They also have a tail that is longer than that of other species. They beak has a red color to it but the tip of it is black. The Adelie Penguins have been found to reside in all areas of the Antarctic as well as various islands including Ross Island.


King Penguin

The King Penguin is very large compared to other species. It is the second largest of them all. Full grown, they can be up to three feet tall and weigh up to 35 pounds. King Penguin males are generally taller and weigh more than the females. There is no denying the overall beauty of this particular penguin. Their tall and slender build gives them a type of posture and movement that you usually don’t see with other penguins. The body is a dark black and blue mix all down the back. They have dark yellow on their bill and the back of the neck. They also have this yellow color on the front as the bit of black there gives way to the rest being all white. There are quite a few locations out there where the King Penguin is able to call home. Most of them are found in the sub Antarctica region. Other locations include the Falkland Islands, Prince Edward Islands, and Southern Georgia. Smaller numbers of them are scattered throughout both New Zealand and Australia. The King Penguin definitely consumes plenty of meat items daily. They enjoy feeding on krill, small fish, squid, and a variety of crustaceans.



Galapagos Penguin 


Classified as one of the smaller species of penguins, the Galapagos are quite interesting. They aren’t more than 5 pounds when fully grown or taller than 20 inches. There are some distinct markings that help make it easier to identify this type of penguin. For example they feature a head that is black but has a white border that starts out behind the eyes and runs from both sides to meet at the base of their throat. The belly is white with small black spots scattered on it. When they are adults, you will notice what looks like an upside down horseshoe there. It can be very small or it can range across the entire belly region. The name for this particular penguin comes from where it lives. Along the Galapagos Islands is where you will find them. Smaller colonies are also found in this same generally vicinity but on other islands. Two that have a constant Galapagos Penguin representation include Fernandina Island and Isabela Island.






Humboldt Penguin




This is an average sized penguin with a full grown weight of no more than 13 pounds. When they mature they will develop a black breast band. It will extend all the way down to the thigh region. They only have one band around their neck which is an easy way to tell them from the Magellanic Penguins that live in close proximity to them. The Humboldt Penguin lives in South America along the Pacific Coast. It is found in both Chile and Peru. They enjoy the warmer climate compared to many other types of penguins out there. They live on the rocky areas around the shores. Due to the warm temperatures where the Humboldt Penguins live, they don’t engage in the migration process. The physical appearance of these penguins is very much the same for both the males and females. It is from observing their behaviors though that they are able to be distinguished from each other.




Macaroni Penguin 

You will be able to tell Macaroni Penguins from other species due to the colors of the feathers on top of their heads. They are yellow and black and very dark in color. The Macaroni Penguin isn’t able to fly due to their wings being very stiff. However, they are excellent swimmers. They are about 12 pounds as adults and a height of approximately 28 inches. Each year the Macaroni Penguin will molt. This is the process of losing their feathers and then them being replaced. Their appearance is quite different during that period of time. You will find that the Macaroni Penguin enjoys the cooler climates. They are only found along the Antarctic Peninsula and the Sub Antarctic regions. They do take part in migrating annually and during that time you will find them in different locations than they would normally reside. They are excellent swimmers thanks to the design of their flippers. They form very large colonies. Social interaction is very common, especially among the young. Once they don’t need to be kept warm by the parents these young group together. The females tend to be more aggressive with this type of penguin.


Little Blue Penguin-Fairy Penguin



The Little Blue Penguin is one quite small compared to other species. In fact, it is due to this small size that it is also referred to as the Fairy Penguin. It is the smallest of all the penguins in the world. It can weigh up to 2 pounds and it would be taller than 16 inches. They have a deep blue coloring to them which is why they have been named the Little Blue Penguin. This blue color is on top of their head and all down their back side. The front is white.
The majority of Little Blue Penguins are found in Australia. Other places they have made their home include New Zealand and Chile. A small number of them have been identified around Tasmania as well. The colonies are well defined for the Little Blue Penguin. They will live in it all year long. Each mating pair has a burrow that they maintain. They will return to the same nesting area year after year. They are highly social with each other in the colony as well.




Rockhopper Penguin 

With some very colorful feathers on their heads, it is hard to mistake the Rockhopper Penguin for anything else. These crazy colors that are on feathers in all directions remind many people of the punk rock generation. It is due to this distinction that they are classified as crested penguins. They are the smallest in that category, weighing no more than five pounds when they are adults. Depending on the time of year, you may notice them without feathers. This is called molting and they will regrow new ones. Every year this is going to occur and temporarily alter the appearance of the Rockhopper Penguins. You will find the majority of the Rockhopper Penguins found out there around the Antarctic. Some people find the behaviors of the Rockhopper Penguin to be silly but very interesting. They have been named after one such behavior. They can be observed hopping over the rocks along the areas where they live rather than just walking. They are very aggressive with each other which is different than the social structure for other types of penguins. They will fight over food, nesting locations, and even initial mating partners. It is very interesting to watch how Rockhopper penguins interact with each other. They have plenty of non verbal methods that are simple enough to notice. They include shaking their head, moving their flippers, bowing, and preening.



African Penguins

Also known as the Black Footed Penguin, the African Penguin is one that many people enjoy viewing. They are about 11 pounds in weight and up to 27 inches tall. You will be able to easily identify them due to their physical characteristics. They are black in color along their head and their backside. One the belly the feature black spots and black lines. If you observe these spots and lines, you will notice they are different for each one. This is a great way for researchers to be able to track the behaviors and movements of particular members of a colony of African Penguins. The Southern coast of Africa is where you will find the majority of the African Penguins. There are 24 known colonies of them around this continent. There is no place else on Earth where this species of penguin is found. This is one of the most calm types of penguins out there. In fact, in some of the viewing areas tourists can get extremely close to them in their natural environment without fear of an aggressive attack. It is reported that people can come within three feet of them before they will move away.

Sunday 20 February 2011

History of Penguins




     Penguins (order Sphenisciformes, family Spheniscidae) are a group of aquatic, flightless birds living almost exclusively in the southern hemisphere, especially in Antarctica. Highly adapted for life in the water, penguins have countershaded dark and white plumage, and their wings have become flippers. Most penguins feed on krill, fish, squid, and other forms of sealife caught while swimming underwater. They spend about half of their life on land and half in the oceans. 


     Among extant penguins, larger penguins inhabit colder regions, while smaller penguins are generally found in temperate or even tropical climates. Some prehistoric species attained enormous sizes, becoming as tall or as heavy as an adult human. These were not restricted to Antarctic regions; on the contrary, subantarctic regions harbored high diversity, and at least one giant penguin occurred in a region not quite 2,000 km south of the equator 35 mya, in a climate decidedly warmer than today.
There are 17 to 19 known species worldwide, depending on whether the two Eudyptula species are counted as distinct. Although all penguin species are native to the southern hemisphere, they are not, contrary to popular belief, found only in cold climates, such as Antarctica. In fact, only a few species of penguin actually live so far south. Three species live in the tropics; one lives as far north as the Galpagos Islands (the Galapagos Penguin) and will occasionally cross the equator while feeding.

   The largest species is the Emperor Penguin (Aptenodytes forsteri): adults average about 1.1 meters (3 ft 7 in) tall and weigh 35 kilograms (75 lb) or more. The smallest penguin species is the Little Blue Penguin (also known as the Fairy Penguin), which stands around 40 cm tall (16 in) and weighs 1 kilogram (2.2 lb). Generally larger penguins retain heat better, and thus inhabit colder regions, while smaller penguins are found in temperate or even tropical climates. The rarest type of penguin is the yellow-eyed penguin (Megadyptes antipodes) and is probably the most ancient of all living penguins: adults average about 65 cm tall and weigh 5-6 kilograms.
     Most penguins feed on krill, fish, squid, and other forms of sealife caught while swimming underwater. They spend half of their life on land and half in the oceans.
One of the most baffling forms of behavior of the penguin comes when a mother loses her chick, either due to its being unable to endure its first storm, or due to other reasons such as predators. When a mother loses its chick, they have been known to actually attempt to steal another mother's living chick- presumably in order to deal with the grief of the loss.


    This behavior has amazed scientists, as it is an emotional outburst opposed to an instinctual behavior; something many wild animals do not exhibit when losing their young. Many have used this as prime evidence for decades that many animals have near human-like emotions and feelings, often for the sake of animal rights. Naturally, the other females in the penguin groups dislike this behavior and will help the defending mother keep her chick.


    This behavior, however, might be better explained as a means for the female, or the male, to retain the full cooperation of the other parent in rearing the young, given that the bonding is monogamous; most likely there are differences between males and females in regards to the likelihood of chick-robbing and between species in relation to whether the monogamy is seasonal or permanent. Penguins seem to have no fear of humans, and have approached groups of explorers without hesitation.


     The evolutionary history of penguins is poorly understood, as penguin fossils are rare. The oldest known fossil penguin species are the Waimanu, which lived in the early Paleocene epoch of New Zealand, about 62 million years ago. While they were not as well adapted to aquatic life as modern penguins (which first emerged in the Eocene epoch 40 million years ago), Waimanu were flightless and loon-like, with short wings adapted for deep diving.


      These fossils prove that prehistoric penguins were already flightless and seagoing, so their origins probably reach as far back as 65 million years ago, before the extinction of the dinosaurs. Penguin ancestry beyond Waimanu is not well known, though some scientists (Mayr, 2005) think the penguin-like plotopterids (usually considered relatives of anhingas and cormorants) may actually be an early sister group of the penguins, and that penguins may have ultimately shared a common ancestor with the Pelecaniformes.