All the weight of a human body except the leg on the ground most be supported by the pelvic bone almost all the time while erect, including tthe impact loads from movement plus objects being carried. Cat and dogs carry items in their teeth (kittens, pups and prey but never boxes of tools!). Cats and dogs have four legs to share the load and can use two or more at a time for impact when jumping, etc. It is the stress of load that strengthens bone as an animal or human develops. During a lengthy stay flat on back in a hospital humans actually lose calcium from their bones. Daily exercise (even brisk walking) helps maintain healthy bone mass and density.
2006-10-16 03:03:58
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answer #1
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answered by Kes 7
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Because volume and therefore weight increases exponentially relative to linear dimensions. A cat is perhaps 1/5 the length of a man, but is only 1/40 the weight. So the bones needed for support are proportionately lighter. The bones of a cow on the other hand are massive compared to those of a human being.
2006-10-16 10:34:15
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answer #2
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answered by PaulCyp 7
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Because it needs to be in proportion of their body. Their a lot smaller than humans, so they have smaller pelvis's.
2006-10-16 09:58:44
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answer #3
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answered by Anonymous
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Maybe because all our weight is concenterated there while sitting
2006-10-16 09:57:16
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answer #4
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answered by words_worth_in 1
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they dont have to stand upright to walk
2006-10-16 09:56:11
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answer #5
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answered by Mopar Muscle Gal 7
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