Can you imagine coming back from a foraging trip and having to face a whole crowd of youngsters, all looking the same? How do they know their families? It always fascinates me that penguins can find their youngsters in a crowd of identical young penguins – the mother or father might have been away for weeks collecting food, and when coming back are faced with thousands of look-alikes. How do they know which one is theirs?
After marching up to 125 miles across the sea ice, female Emperor penguins must locate their chick among the thousands of others in the colony. Unfortunately, the chicks and their dads do look exactly the same, and to find her man and their chick, she issues a unique call that her male partner can identify (this must be hard when everyone else is calling out too!). In most penguin species, including the Galapagos, parents and offspring recognize each using vocalizations and location. Galapagos penguins apparently not only find their own chick but are sometimes themselves found by their own fully grown offspring who have actually fledged and left the nest but will continue to pester their parents for food - and if the bounty of the sea has been plentiful, the parents oblige. But in many seabird species, it’s not uncommon for parents carry on feeding their young after they have fledged, at least for a limited period of time.
Where are penguins found?
Penguins are a strange species. Classified as a bird, they cannot fly, and despite sometimes laying two eggs, they will discard one and raise the other (how do they pick the lucky one?). Everyone imagines penguins in Antarctica or taking a break on a passing iceberg, but penguins are also found in South Africa, Chile, Peru, Galápagos Islands, New Zealand, Australia and a number of sub-Antarctic islands. Penguins are very nearly exclusive to the southern hemisphere, but Galapagos penguins live right on the equator and fledgling care is only one of several behaviours that distinguish them from other penguins. Many of these peculiarities make sense when considering where they live - the Galapagos Islands straddle the equator. Thus, they must cope with extremes of punishing heat on dry land and relatively cool ocean waters.
As a result, Galapagos penguins adjust their behaviour based on food availability. They apparently prioritize moulting, the process of shedding their old coat of feathers and replacing it with a new one. All other penguin species moult just once a year, while Galapagos penguins moult twice a year, getting rid of worn, sun-bleached, algae-covered feathers. Most other penguin species breed before moulting, but only after moulting do Galapagos penguins breed, and they can skip a breeding window entirely or totally abandon their chicks if food is scarce.
Weirdly, researchers believe that there are anywhere from 17 to 21 different types of penguins, but common opinion is 19. More research is needed to determine whether certain penguin types are subspecies or species in their own right.
Here are some Interesting things about penguins
They have no teeth, but their mouths and tongues are lined with spines that point back towards their throat, making it easy for them to swallow prey such as squid, shrimp and fish. A group of penguins in the water is called a raft but on land, they're called a colony, a rookery or a waddle (with good reason!) And their tuxedo-like colouring is no accident – it’s called countershading, to help camouflage themselves from potential predators. When seen from below a white belly better blends in with light-filled surface waters, while from above a black back looks like the dark hues of the deep ocean. And to protect against the cold they have a fat layer that protects them while in the sea.
On the land, however, their feathers also help to keep them warm - their feathers aren't like the large flat ones that flying birds have, but are short with an under-layer of fine woolly down. And the huddling you often see has two purposes, to deter predators, and in frigid habitats, it helps them share warmth and conserve energy.
Totul despre pinguini
Trimite-ne comentariile sau părerea ta despre acest articol.