makes them better streamlined i would guess
The lack of teeth or a heavy bony jaws reduces a bird's weight even further.
It is said that birds have no marrow in their bones, which allows them to be lighter for flight. This is partially true... The major reductions in weight however comes from the lack of large jaw bones, no teeth because no jaw bones, small skull, and very little tail [bone]. There is no marrow in the bones of birds, but this doesn't make them lighter it makes the bones stronger. My source (look under "The Bird Skeleton"): http://www.earthlife.net/birds/anatomy.html#4 In addition to the above, some birds' respiratory systems circulate air through some of the bones in order to complete the respiratory circuit. Birds do not breathe in and out like mammals. Their lungs act like a bellows to move the air in through their mouth and out through their nostrils. This permits a much greater oxygen flow, which in turn allows their muscles to create the high energy levels needed for flight.
lala that's what I think
There are no birds that do not have wings. Even the flightless birds such as emus, ostriches, kiwi, rheas and cassowaries all have wings. It is just that their wings are undeveloped and they lack the chest muscles necessary for flight. The kiwi's wings - which many people incorrectly believe are non-existent - are about 5cm in length.
Recent discoveries suggest that the earliest birds descended from a small dinosaur known as Archaeopteryx, which developed feathers. Possibly to keep warm.Birds all have feathers, and their young (as the dinosaurs before them) hatch from eggs. The flying birds have hollow bones to reduce weight, but most ground -dwelling flightless birds have more conventional bones. Birds mostly care for their hatchlings, apart from exceptions such as the Cuckoo family.In general the flightless birds such as Kiwi, Ostrich Emu, etc lack a keel bone in their chest to which flight muscles would otherwise attach. This family probably never had flight, but that is subject of dispute.
because it is a worm and it is always kept moist because it lacks a respiratory system.
It is said that birds have no marrow in their bones, which allows them to be lighter for flight. This is partially true... The major reductions in weight however comes from the lack of large jaw bones, no teeth because no jaw bones, small skull, and very little tail [bone]. There is no marrow in the bones of birds, but this doesn't make them lighter it makes the bones stronger. My source (look under "The Bird Skeleton"): http://www.earthlife.net/birds/anatomy.html#4 In addition to the above, some birds' respiratory systems circulate air through some of the bones in order to complete the respiratory circuit. Birds do not breathe in and out like mammals. Their lungs act like a bellows to move the air in through their mouth and out through their nostrils. This permits a much greater oxygen flow, which in turn allows their muscles to create the high energy levels needed for flight.
lala that's what I think
limiting factor
If your teeth keep chipping off, it could be a lack of calcium in your diet. Other possible reasons could be decay or lack of other nutrients in the body.
teeth
wrybill, crossbills
Actually birds don't have urinary bladder.
lack of calcium in your body causes white stripes on teeth and nails.
When you can no longer nomm dem burdz, you haez a lack ov calcium.
Soft teeth can be a genetic factor and a lack of Calcium. Speak to your dentist so you can take care of your teeth and gums to the best of your ability.
There are no birds that do not have wings. Even the flightless birds such as emus, ostriches, kiwi, rheas and cassowaries all have wings. It is just that their wings are undeveloped and they lack the chest muscles necessary for flight. The kiwi's wings - which many people incorrectly believe are non-existent - are about 5cm in length.
Recent discoveries suggest that the earliest birds descended from a small dinosaur known as Archaeopteryx, which developed feathers. Possibly to keep warm.Birds all have feathers, and their young (as the dinosaurs before them) hatch from eggs. The flying birds have hollow bones to reduce weight, but most ground -dwelling flightless birds have more conventional bones. Birds mostly care for their hatchlings, apart from exceptions such as the Cuckoo family.In general the flightless birds such as Kiwi, Ostrich Emu, etc lack a keel bone in their chest to which flight muscles would otherwise attach. This family probably never had flight, but that is subject of dispute.