2006-09-02 04:32:14 · 32 answers · asked by dundeeflower_4 1 in Science & Mathematics ➔ Zoology
Mostly for walking on !
2006-09-02 04:33:43 · answer #1 · answered by any 4 · 1⤊ 1⤋
Animals have a wide range of different amounts of appendages. From Insects with 6 to 100 legs and Molluscs with one foot, 8 and 10 legs to mammals with 4. (Whether arms, legs or fins) So in short Not all animals have four legs!
2006-09-06 04:09:24 · answer #2 · answered by TT 2 · 1⤊ 0⤋
This question is more interesting than many of the sarcastic respondants have appreciated. Obviously three legs provides the most stable base for a stationary object, like a stool. IIf you've ever played with robotics you've probably encountered six legged robots that alternately move tripods in order to walk. I think there are two reasons. Firstly, symmetry, an odd number of legs is something that nature just doesn't like. Secondly, movement. Six legs or more may be very stable, but they don't allow for fast or flexible movement, two legs require a huge amount of brain power just to control balance. hence four seems to be the magic number.
2006-09-02 10:40:50 · answer #3 · answered by Anonymous · 0⤊ 1⤋
Evolution. Life began in the sea. When they came on land, they found it a lot convenient to have legs. So they evolved....some with 4, others have many like insects. Some 4 legged living things further adapted to turn some of the legs into wings. Man adapted to his surroundings by turning his front paws into hands and walk on his two hind legs.
2006-09-02 04:46:48 · answer #4 · answered by Anonymous · 1⤊ 0⤋
Vertebrates - amphibians, reptiles, mammals and birds - have four limbs because they all descend from fish.
The basic structure of a fish and all other vertebrates is two hoops connected by long spine. The hoops are the pelvic (pelvis) and pectoral (shoulder) girdles. For stability and movement in the water only two limbs are needed on each girdle. Fewer leads to instability, more either confers no extra benefit or that benefit is outweighed by the costs of a creatures body building the extra limbs.
2006-09-03 03:21:28 · answer #5 · answered by cavanuklil 1 · 1⤊ 0⤋
There's an evolutionary advantage to going about on four legs. It takes a lot of effort to walk on two.
2006-09-02 04:34:59 · answer #6 · answered by Christopher C 3 · 0⤊ 1⤋
Not all animals have 4 legs. Look at fish, invertebrates, birds etc. Animals have various numbers of legs according to the way they have evolved to fit their environmenal niches.
2006-09-05 14:55:28 · answer #7 · answered by ms.toinette 3 · 1⤊ 0⤋
They don't - some have two (us); some have six (insects), some have eight (spiders, octopii); some have ten (arthropods, squid); some have dozens (centipedes, millipedes).
BTW: not to be rude but I see yr handle cropping up evry few minutes. Are you on a bet to ask the most silly questions in the shortest amount of time?
2006-09-02 04:44:56 · answer #8 · answered by narkypoon 3 · 0⤊ 1⤋
at one time we all had four legs! we walked our hands just like animals walk on there hands!
2006-09-02 04:34:21 · answer #9 · answered by 014beth 2 · 1⤊ 0⤋
To walk on?
Stop them falling over?
Try taking a one legged on for a walk then you'll know.
2006-09-02 04:38:56 · answer #10 · answered by Anonymous · 0⤊ 1⤋
Some animals don't have four legs.
example: Hen, duck,
2006-09-02 04:36:56 · answer #11 · answered by iyiogrenci 6 · 1⤊ 0⤋