What biological aspects that cause one species to live longer than another species?
We’re not going to discuss about psychological aspects that contribute in longer lifespan such as stress-free environment, adequate nutrition, health care, social stimulation, living in captivity VS nature, etc. We’re going to see things from other fields/point of views.
Take this as simple example:
A small chihuahua can live far longer than a big St. Bernard since it requires less effort to sustain its heart and other vital organs, etc. A rat that is almost the size of a chi live no more than 2 years. The lifespan of an elephant could be as long as the average lifespan of human. Cold-blooded species could live longer due to decreased metabolic rate (let us ignore them for awhile and focus on mammal, for now). Etc,etc. There are many other argumentative examples that I couldn’t write all of them here.
So I want to hear your personal scientific explanation/opinions toward this matter. Please don’t just say it’s already in genetic. You could be as argumentative as you want.
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11 Answers
Pretty much it’s the size and speed of their heart rate, I think. Elephants live a looooong time. Tortoises live even longer.
It depends on the environment. Does the food they eat hit back? Do they have a lot of competition for the same food source? Is the food they eat helping them live longer? Or just filling them so they don’t starve?
Ive always learned it as size and speed of heart rate as well. I dont know how much truth there is in this but I remember reading something like most animals over their life (barring deformities, early death, etc) have the same amount of heart beats. Animals like humming birds where there heart is beating very quickly(~250 bpm) all the time only live around 3 years, but as @Dutchess_III said animals like elephants live long lives and have a very slow heart beat (~30 bpm)
Dogs are actually an unusual exception to the (very) general rule that larger = longer lived. In most species, it has to do with the metabolic rate.
Great question!
The heart rate calculation is an OK quick and dirty one (at least for mammals), but it doesn’t tell all. For example, a chinchilla and a large rat are about the same size and have similar metabolic rates, but the rat lives 2 years and the chinchilla 25. Most birds have very fast metabolic rates but live much longer than mammals.
No one really knows why some animals live longer. But there are some trends. Longevity is correlated with increased body size, increased brain mass, decreased metabolism, and greater length of the juvenile period before puberty.
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From an evolutionary standpoint it doesn’t matter how long individuals live, so long as they reproduce. Mayflies (which live a day or less) and giant toroises (which live up to 200 years) both have “selfish genes” that occupy host bodies selected to preserve themselves. Interesting question.
Thank you all. I also found this interesting and debatable article about lifespan.
@crisw lol. Oh! I’m so sorry! I’m so ashamed. It’s my bad habit to just read all the thread and delay the link (it doesn’t happen very often,though). I should have checked the link before I say something next time. I have no bad intention. Just a bit careless…sometimes. I’m apologize again and I hope you don’t think that I’m a plagiarist jerk. I like your responses by the way.
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