why can't penguins fly?
465272
Long ago the ancestors of penguins were birds that could fly.  However, they evolved to become superb divers, and in the process lost the power of flight.  A flying bird has to minimise its weight.  For example, all flying birds have hollow bones.  In contrast, to be a successful diver a penguin wants to keep it's weight high, so they have solid bones. Penguins are excellent divers, they can dive to depths of 300m and remain down for up to 20 minutes.  While penguins cannot fly in the air, they do seem to fly through the water - if you ever get the chance to see penguins swimming in a large and deep pool you will never again say they can't fly!
553787
a bird can fly but a fly can't bird.
16098
Penguins do not live at the north pole. They live at the south pole, New Zeland, and southern africa.
925346
It's a mixture of the above answers: the penguin does control the flow of blood to the feet, by varying the diameter of the vessels carrying blood into the feet. When it is cold they reduce the flow (this means less blood to heat up when on its way back into the body). The second method of control is by way of the countercurrent heat exchangers at the top of the penguin's legs. The blood vessels break into many smaller vessels that are very close to similar small vessels coming back up into the body. All the heat flows from the warm blood into the cold, meaning little warmth is carried down into the feet and lost to the environment, keeping the heat in the penguin! The feet are a degree or two above freezing, which is just above what they would get frostbite at, but still minimises heat loss.
292689
On extremely cold days many birds will roost to conserve heat. If they take to the air they expose their underwings and bodies, and the short insulating feathers under the flight feathers are exposed to the cold air, so they no longer provide adequate insulation.
171228
Pigs can't fly.\n\nPeople are more concerned about birds that are migratory and can carry the disease form place to place.
326897
You mean emperor penquins. They migrate hundreds of miles inland on Antarctica. They have to move inland to find land solid enough to support the weight of thousands of nesting penquins. The ice shelf around the continent would not be sufficient.
580440
Birds. Just to fly they'd need more brain power.
497390
No, we couldn't fly if we had wings. We're much to heavy for one thing. Flying birds have hollow bones and many other adaptations for flight (like a "keel" on their breastbone that the flight muscles attach to and specialized respiratory systems). It's a good thing we're smart enough to make things like planes, because that's the only way we're getting in the air.
148668
Well, because of their evolutionary history. Penguins (Sphenisciformes) evolved when the appearance of the Earth was quite different, and all southern landmasses formed a supercontinent called Gondwana. After Gondwana split to form Africa, South America and Australia/New Zealand, they went on evolving within the same geographical area. \nPenguins would find it almost impossible to cross the Equator and colonize the Northern Hemisphere, mainly because their adaptations to the cold Antarctic climate prevent their survival in warmer climates (the only genus of penguins that has really colonized warmer areas is Spheniscus: Spheniscus mendiculus lives in the Galapagos islands, and other species occur in southern Africa and Oceania).\nIn addition, as it has been mentioned, the ecological niche of penguins in the Southern Ocean waters is occupied by the Alcidae (auks, guillemots and puffins) in the Northern Hemisphere. \nActually, the name "penguin" was applied to the Spheniscidae because they were found to be similar to the original owner of the name, the extinct Pinguinus impennis (the great flightless auk). In Spanish, the name "pingüino" replaced the original "pájaro bobo" (=dumb bird).\n\nPenguins look superficially similar to auks, mainly because they have similar adaptive traits: black and white color pattern (common in many pelagic animals), upright posture and clumsiness when moving on land. But auks can fly, whereas all penguins are flightless.
988952
because gravity points to the center of the sphere, so no matter where you are on teh sphere, the down direction is towards the center of teh planet, wich allows penguins in teh south pole to walk on teh surface of the planet.\nIf you look at constelation however, they do appear upside down when viewed from below the equator, proving that we are walking on a sphere
403561
yes penguins have sex! no they dont suck it, there feet are made for the ice so no, an yes all animals have sex organs!\ngo to the site below! to see them in action!
117345
Penguins do not live in the north pole but they DON'T only live at the south pole. There are penguins in some  southern countries as well. New Zealand for example.
939944
Ostriches can't fly because they have tiny (vestigial) wings. Ostriches are large birds, and weigh quite a bit - and therefore would need HUGE wings in order to fly. We're talking a wingspan of over 30 feet! There is a point where the weight of the body and the need for longer/bigger wings is not advantageous for a species. The ostrich is way beyond that metaphorical cut-off point. \n\nI hope this helps!
270627
Penguins, like other flightless birds (ostriches and emus) evolved from birds that could fly.\n\n65 million years ago the ancestors of today's penguins flew over the ocean and dove down into the water for food.\n\nOver millions of years, their hollow bones became solid and they could no longer lift themselves out of the water to fly. But, their heavier bones made is easier for them to dive down into the water.
144449
you could flap your arms all day long a (BMPH) Billion Miles Per hour.heheh And you never get lift. See to under stand how birds fly you have to understand a birds body. First off a birds bones are hollow. Meaning less weight. Secondly the birds wings are shaped like a windfoil which gives lift. to explan how a wing works we will go into alittle physics of flight. To understand flight you have to understand how the wing is designed. \n\nfirst take a peice of postit note from one of the 5x3 inch pads. you need a pensile. bring the bottom side of the post it note to the top side where it is sticky. stick it together. Now you have a piece of paper simular to a tear drop. what you going to do is run the pencle between the opening to the other side. let the pice of paper float freely. hold the pencile with both hands one on one side of the paper and the other on the other side of the paper. Not put the not about 5 inches in front of your mouth and blow. Notice what happens the paper lifts. This is what is called lift. This is how birds fly. basicly when you blow on the paper the under side high presure goes under and low presure goes over the top. We will call it a win for now. But pending on how the wind is hitting it will depend on what direction the wing will go. If the tail end is faced up then the wing will go down it it's faced down the wing will go up. When it goes up that is called lift. and thats how birds fly.
489569
Just a quick thought here that may help you.  Under "cold blooded" - or ectothermic - we understand an organism that does not produce a relatively constant body core temperature by means of metabolitic activity etc., but rather regulates its temperature by shutteling between warmer and coller areas.  It takes on the temperature of its environment.  That would be detrimental in case of an animal living in antarctic conditions.  A penguin's blood would freeze, there would be crystalization, and the cells would eventually burst.  In other words, the penguin would be a very cold toast.\n\nNow, there are however ectothermic organisms in arctic and antarctic oceans, which maintain blood flow by using a chemcial anti-freeze.  This has been found, for example in some fishes (the plural is allowed here, since we aretalking about more than one species).  But penguins don't have anything like that and do not need it.  As others have mentioned above, they are very well insulated endotherms (maintain a relatively stable core temperature).\n\nHope this helps in addition to the other answers.