Emperor penguins may be recognized by black color on the
back, bright white on the front and colorful yellow or orange feathers around
their necks and heads. They are the tallest with an average of about 4 feet.
Fossils recently recovered in the Antarctic peninsula revealed that it used to
be home for a giant penguin (Roberts, S.J. et al, 2017). During the arctic winter, they are the only
animal species to inhabit Antarctica open space, where temperature can drop to
as low as -60°C. Their body is specially adapted to survive the harsh climate: a
good reserve of insulating body fat, multiple layers of scale-like feathers,
proportionally smaller beaks and flippers, preventing heat loss. Their arteries
and veins are situated close together allowing them to recycle their own body
heat (Australian Arctic Division circular about penguins, June 2017). They choose to live in the most desolate, coldest and
windiest places of the earth during the season of 24-hour darkness. These penguins
can travel up to about 50 miles to reach stable breeding grounds on the thick
Arctic ice. The emperor penguins are super swimmers and impressive divers. Their
aerodynamic bodies and strong flippers make them excellent swimmers,
reaching speeds of 3.4 m/s. (Freeman, J., 2015). Emperor penguins can stay
underwater for over 22 minutes at a time and can dive over 550m as they hunt
for food. They have been found to have an increased ability to store oxygen in
the body, the ability to tolerate low levels of oxygen in the body and the
ability to tolerate the effects of pressure.
British and Australian scientists
discovered more emperor penguin colonies on ice shelves (Fretwell, P.T. et al
2014). The average lifespan of emperor penguin is typically 20 years in the
wild, even though they live in very extreme conditions where the cold could be
unbearable for most animals living on this planet. Although the average life
span is about 20 years, many scientists estimated 1% of emperor penguins
hatched might go to 50 years. According to Trathan
et al, most of the emperor penguin population consists of five years and older
(Trathan, P. et al, 2011).
et al., estimated the population of emperor penguins (Aptenodytes fosteri)
using a single synoptic survey. Using a combination of medium resolution and
Very High Resolution (VHR) satellite, they examined the whole continental
coastline of Antarctica imagery to identify emperor penguin colony locations.
The remotely-sensed images were then analyzed using a supervised classification
method to separate penguins from snow, shadow and guano. Actual counts of
penguins from eleven ground truthing sites were used to convert these
classified areas into numbers of penguins using a robust regression algorithm.
Fretwell et al found at
least 46 breeding colonies of emperor penguins. They estimated more than
200,000 breeding pairs. Based on published values of the relationship between
breeders and non-breeders, this translates to a total population of about
600,000 adult birds (Fretwell, P et al, 2012).
The weight of the adult penguins varies from 50 to 100 pounds (CRC
Handbook of Avian Body masses by John B. F Dunning. CRC press (1992), ISBN
978-0-8493-4258-5). Like all penguin species,
emperor penguins have streamlined bodies to minimize drag while swimming, and
wings that are more like stiff, flat flippers (Williams, Tony D., 1995). The tongue is equipped with
rear-facing barbs to prevent prey from escaping when caught.
It is hypothesized that the emperor Penguins never walk on
solid ground. The emperor penguin feed mostly on Antarctic silverfish, but sometimes
other fish, and some species of squid. When they need to build up their store
of fat, before a molt or at the beginning of breeding season, the food quantity
ingested is doubled. Emperors are near the top of the Southern Ocean’s food
chain and have few natural predators on land due to the hostile conditions of
their habitat. Emperor Penguin chicks are preyed upon by other birds like the
Southern Giant Petrels and South Polar Skua. When they return to the ocean,
adults are preyed upon by Killer Wales and Leopard Seal
for many wild mammals and birds, prolonged periods of feeding and fasting is
normal phenomenon of life in penguins. The fasting period goes on due to
unavailability of food. During winter season, feeding competes with other
activities, such as survival priority, for example, molting, reproducing and
migrating. Molting is simply defined as shedding their feathers. Usually Penguins undergo one
complete molt yearly usually after their breeding season.
feed mostly on sea fishes, crustaceans and squids, however, they must stay on
land for extended periods when breeding, mainly during incubation. In addition,
penguins entirely replace their whole plumage each year and must spend a long
time fasting ashore because the consequent reduction in thermal insulation
precludes staying in cold Antarctic and sub Antarctic waters for feeding. The duration of fasting of molt varies from
2-5 weeks. (Putz and Plötz 1991).
To keep themselves warm
and dry, the feathers of penguin are very important. In frigid ocean water. The
penguin’s molt is sometimes
called a catastrophic molt,
because unlike most birds that will molt a
few feathers at a time, penguins molt all
of their feathers all at once (Webster R.K., et al, 2016).
For most penguins, they undergo
alternate periods of anorexia on land and hyperphagia at sea. Larger the
penguins, the fast period is longer, whereas, smaller penguin’s fast days are
1-3 days. The male emperor penguins support a four month fast. In the middle-sized
penguins, the duration of breeding fast is about 2 weeks. In the king Penguin
species, because of the winter food shortage, that temporarily halts their
growth varies from 1 – 5 months.