The Straight Dope... hilarious website of random questions finally answered.

If this article alone doesn't convert you, I don't know what will.

Basically, it boils down to this singular guy (Cecil) who responds to some of the weirdest questions that most people WANT to ask but never do. He then answers them in a generally funny way but takes great lengths to actually explain it and give some of the sources he used. He isn't the only contributor, but he is the main one and the other contributors (from the few articles i have read) aren't quite as humorous but still do a good job (often better) of answering the questions.

Here is a snippet of the above article, as he gets called out and hilarity ensues:

Why do pigeons bob their heads?
April 13, 1979

Dear Cecil:

Can you in your infinite yet magnanimous wisdom explain something that's been troubling me for years? When pigeons bob their heads as they walk is it because their legs are connected to their necks or what?

— Dennis A., Highland Park, Illinois

Dear Dennis:

Of course not. As any fool can see, a pigeon's legs are connected to its body--and it's a good thing, because the pigeon would look mighty funny if it were assembled according to the offhand anatomy you describe.

Basically the pigeon's back-and-forth head motion--not exactly a bob--helps it keep its balance when walking. The pigeon's legs are located pretty far astern, and if it kept its head forward all the time it would probably tip over. This would expose the pigeon to the ridicule of the community. Instead, what it does is move its chest forward in time with one leg, and its head forward in time with the other leg. Thus some weight is always trailing a little abaft the port beam, as we say. Many fowl have similarly peculiar gaits, because they cannot afford orthopedic shoes.

I had a similar question for one of my professors in Biology. It went a little something like, "if bats can see somewhat, but STILL use sonar, what do they actually see in their heads?" The idea in my head was that sonar is used to detect their prey, and if they have poor vision, do they just close their eyes and rely on the sonar images to guide them? Does their vision combine with the sonar images? Unfortunately, I cant remember his answer. Maybe ill throw it at Cecil...