4 ms·

Yes. Waterfowl have hollow bones. They may be denser than a hummingbird's, but that does not mean they are solid. Raptors have a slower heartbeat than hummin

• deleted 5y ago
  [deleted]
• jelliclesfarm 5y ago
  https://www.birdspot.co.uk/bird-reproduction/do-birds-have-penises https://www.birdspot.co.uk/bird-reproduction/do-birds-have-p... [..] In birds, apoptosis of the genital tubercle is triggered by a gene called Bone morphogenetic protein 4, or Bmp4, a protein involved in bone, muscle, cartilage, and limb development. In the majority of birds, Bmp4 gets switched on and blocks the genital tubercle from developing into a penis so they either lack one altogether or it’s so small as to be rendered useless. In ducks and other birds which grow penises, Bmp4 remains switched off and the genital tubercle develops into a functioning penis. But although this explains how most birds end up penis-less, it doesn’t explain why. And scientists are still not sure of the answer to that conundrum. There are several plausible explanations. It could be that the loss of the penis was an unfortunate side-effect of Bmp4 triggering other changes to body parts such as the development of feathers, or the variations in beak size. A bird without a penis carries less weight and therefore would be able to fly more easily, although this theory is unlikely when you consider that fact that ducks make some of the longest migrations of all species of birds. And most flightless birds or birds who fly very little, other than the ratites, have non-existent penises.[..] Hope this helps.