2006-07-30 17:32:56 · 24 answers · asked by Anonymous in Science & Mathematics ➔ Zoology
Its got to do with how we develop in the embryo. All animal body plans are based on bilateral symmetry (one side looks the mirror image of the other). Hence there will always be an even number of appendages. Echinoderms (starfish, sea cucumbers, sea urchins etc) have radial symmetry - like segments of a cart wheel. They have five legs (or multiples of five). Jellyfish also have radial symmetry based on multiples of six tentacles. I don't know of any animal with just 3 legs though.
2006-07-31 00:29:59 · answer #1 · answered by uselessadvice 4 · 8⤊ 0⤋
God don't like three legged animals so he decided not to make any. Four legged animals are better balanced than the three legged ones.
2006-07-30 17:35:53 · answer #2 · answered by Anonymous · 0⤊ 0⤋
All animals are symetric in nature. In such condition, most of the parts of the animals are in pair (in even number) not in odd number. By nature, any three legged animal will not have sufficient balance while walking or running. Thus by evolution, limbs of any animal are in pair.
Note: In Tamil one proverb is there, "An adament person will always argue that he has a rabit with three legs only".
2006-07-30 18:03:14 · answer #3 · answered by K.J. Jeyabaskaran K 3 · 0⤊ 0⤋
Actually, balancing on three legs would be more stable than on two. Some animals, like the kangaroo, use their tail as a third leg.
2006-07-30 17:37:40 · answer #4 · answered by Terisu 7 · 0⤊ 0⤋
He's talking about animals that are supposed to have 3 legs... Not 3 legged dogs, and I guess it would be for balance... I mean how would it walk? It would look really silly hah
2006-07-30 17:39:51 · answer #5 · answered by toofdogger 3 · 0⤊ 0⤋
there are some in parks where the animals were rescued and some animals are born with three legs
2006-07-30 17:36:04 · answer #6 · answered by yakj 2 · 0⤊ 0⤋
For the same reason there are no animals with an odd-numbered set of legs. Balance is based on symmetry and for symmetry, things will have to be even-numbered.
2006-07-30 17:35:42 · answer #7 · answered by ♪ ♥ ♪ ♥ 5 · 0⤊ 0⤋
There is only one 3 legged animals that I can think of and they are men!!!!!
2006-07-30 17:36:23 · answer #8 · answered by slanteyedkat 4 · 0⤊ 0⤋
Of course they have four legs to be able to balance! How will they even walk if they have three legs??
2006-07-30 17:37:05 · answer #9 · answered by prettypigtails 2 · 0⤊ 0⤋
land walking creatures couldnt balance well on three legs although there are certainly many pets who through accident have 3 legs
starfish can have odd number of legs
2006-07-30 17:38:52 · answer #10 · answered by CF_ 7 · 0⤊ 0⤋