I know this is a weird question to ask but.... Why do animals have 4 legs?
494185
most mammals have four appendages, they just evolved differently. humans evolved into arms and legs with very different uses. rodent type animals have front feet they can use as hands, as do most monkeys. beasts of burden and their predators maintained four legs for obvious reasons.
107735
Animals have bones instead.\n\nHE'S DEAD JIM !!!
114337
Centipedes very, very rarely have 100 legs. Most have between 20 and 50. Some have as few as 8, and a handful of species have 100 or more.
676932
It walks on its feet. \n\nThat answer seems way to obvious. Am I missing something?
1054956
Your speed doesn't depend on the number of legs u have,it depends on the speed of motion of ur legs & ur physical health\n\nexample:\nThe Cheetah is the fastest animal on the earth (it has 4 legs) & \nthe Turtle is the slowest animal (it has 4 legs too)
514687
All mammals are set up on a bilateral plan. Two arms, two legs, two eyes, two ears, two nostrils, two halves of the mouth and ideally are identical on either side. It has to do with the way the cells divide. So, humans would have to have an even number of nipples to maintain this symmetry.
454243
Your bones are too dense. \n\nNo joke, the reason birds are capable of flight is due to having hollow bones, making them far lighter.
368677
maybe because they are less agile than that of a smaller animal there by needing only to consume such quantity of food, and also bigger animals has the ability to conserve energy in their body......i guess
860345
No, they aren't.\n\nHumans have a stronger preference for one hand over the other than other animals. That is thought to be due to language being localized on one side of the brain, so motor control gets unevenly dominant (your right side of the brain controls your left hand). Animals don't have the languge skills, and tend to use both paws about equally.
884647
its hard to assign a foot posture to a bird, unless it is a bird that doesnt fly such as a penguin or emu. they have plantigrade foot posture. I do believe other birds are technically plantigrade, but are usually assigned names based on the type of foot. Ie, a raptor would have raptorial feet, a duck palmate, and so on. I would assume bats are the same,but since they dont use their feet for locomotion, its a hard thing to define. good question
302344
It squats, it pushes, out it comes. Much like a dog, I would imagine (except for their being no grass to wipe its feet).\n\nI can't think how it would be any different from any other mammal...
612810
There must be 72 legs as a minimum  (if all chickens)\nBut there are 28 legs more than that\nSo there must be 14 4-legged creatures, contributing 2 extrs legs each to the leg-count.\n14 dogs 22 chickens
689838
Divide 278 by four to get the number of horses, then subract that number of horses from the heads to get the number of ostriches. MAke sense? If it doesn't email me. \n\nR u sure you have the number of hooves right?????? Cause ostriches don't have hooves but there is a remainder of 2 did u mean feet? if u meant feet then...\n\nummm...\n\nOOOO i no.... 123 horses and 0 ostriches! works don't it?
210180
well for a start, insects have 6 limbs, an exo skeloton (or skeloton on the OUTSIDE of their body) Which means they can only grow so big before gravity crushes them, and also more people are scared of insects and arachnids then any other animal... weird huh?
34428
Richard Dawkins attempts to answer this : \n[The embryo of every 4-limbed  vertebrate has five "fingers and toes".]\n"We tend to think that  the possession of 5 digits is deeply stamped in the hands and feet  of tetrapods (4-limbed  vertebrates).  Yet {some early vertebrates] had  7 toes....8 toes....6 toes. ...My tentative guess is that\nin those early times the different species really did benefit from their respective numbers of toes...Later the tetrapod limb design hardened at 5 digits because some internal embryonic  process came to rely upon that number. In the adult the number is frequently reduced...in..modern horses to just one, the middle toe."
274687
Wow, 5 people responded before me and never really answered your question.\n\nThe main question you asked was about "complex animals" compared to land plants. You were understanding this right.  Remember that those early plants were more similar to modern bryophytes (like mosses, liverworts and hornworts).  The vertebrates at that time were all sea creatures (very primitive fish-like).\n\nBy the time the land vertebrates appeared, large trees were abundant and so were insects.\n\nAlso, why do some people insist on using a book that says insects have 4 legs and calls bats birds as their science book?
378634
Chickens' legs bend the same way as ours do. However, it may appear the opposite because the joint that we can see outside its body is the ankle and not the knee. \nThe femur of birds is relatively short and is inside the body, thus it's not visible. The second segment of the leg is a composite of their tibia and some tarsal bones, and it articulates with the third segment, formed by other tarsal bones fused to the metatarsals. \nHere's a picture of a bird skeleton:\nhttp://www.infovisual.info/02/img_en/056%20Skeleton%20of%20a%20bird.jpg\nAnd a photograph of a real one:\nhttp://a-s.clayton.edu/biology/biol3650l/skeletal/bird/bird-lateral.jpg\n\nNow, the next time you have chicken (or turkey) for dinner, you can have a little dissection entertainment! Bear in mind that the parts of the leg that you eat are the first segment (the largest one, you'll see the femur that was articulated to the axial skeleton) and the second segment (the tibiotarsus, also fleshy because of the muscles). \nIn contrast, the third segment (tarsometatarsus) does not have muscles, but tendons that go from the muscles to the fingers. This part is usually covered with scales and is not included in commercially prepared chickens.\n\nHave fun!