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Asked by alannahsinnott to Asif, Laura, Lena, Sean, Viv on 20 Mar 2012.
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Lena Ciric answered on 20 Mar 2012:
There are some trends for life span in the animal kingdom. Mammals have the shortest lifespans (humans live the longest – 80 years), followed by birds (turkey buzzard – 118 years ) and then reptiles (giant tortoise – 152 years). Among the mammals after humans come horses, hippos and then chimps. Smaller mammals have the shortest life spans. It is thought that this may have something to do with the work your heart has to do to pump oxygen around your body. It is thought that there is a maximum number of beats that your heart can make. Smaller mammals hear beats are much faster, so it’s thought that that’s why they live for a shorter time. Their little hearts just can’t hold out… 🙁
Here is a list of lifespans: http://sonic.net/~petdoc/lifespan.htm
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Sean Murphy answered on 20 Mar 2012:
Every species has its own “life history,” or schedule according to which it passes on its genes to the next generation. Some animals invest their time and energy in having lots of babies while they’re young; others use their resources to live longer. An animal might live fast if there are lots of predators around—if you’re going to die young, you might as well get the baby-making over with as early as possible. The long-lived animals, on the other hand, have often evolved some way to protect themselves from predators, such as armor (turtles) or a clever brain (humans).
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Comments
rusty1556 commented on :
Because some get killed