i know that larger animals live longer and smaller ones live shorter. is there any more to it than just that?
2006-10-10 22:40:48 · 13 answers · asked by vixen 1 in Science & Mathematics ➔ Biology
Size really answers your question. Larger animals have larger hearts too, and they are connected to large veins and arteries.
The large hearts can generate great pressures while pumping blood, and due to the sheer quantity, increasing the risk of harming the blood vessels.
It also takes longer for the pressure to push the blood to limbs 'far' away, and therefore increasing the pulse rate would not really serve its purpose.
2006-10-10 22:47:25 · answer #1 · answered by paidpaipa 2 · 1⤊ 1⤋
Several points put forward already are quite correct. Larger animals have larger hearts and can therefore pump more blood in each stroke.
However, on e additional and critical factor is the rate of cellular metabolism in small mammals compared to larger ones. In general, the smaller an animal the faster its metabolism (especially in mammals). This is partly due to rapid loss of heat from muscles and the surface of the skin. For example members of the shrew family effectinely have to eat continuously to replenish the large loss of energy created by their fast metabolic rate.
Larger animals have slower metabolisms and therefore their tissues and muscles do not need some much oxygen [proportionately]. Their hearts can still pump adequate oxygenated blood around the body with a slower rate.
In addition, it is not necessarily true that larger animals live longer than smaller ones. In the dog family the larger dogs, e.g., great danes, retrievers, setters, hounds, etc live significantly shorter lives than the smaller dogs, e.g., terriers, collies, etc.
Great Dane about 8 yrs
Terriers up to 16 yrs or more
2006-10-11 00:20:53 · answer #2 · answered by Anonymous · 1⤊ 0⤋
if the heart rate was fast it the blood would not have time to flow to the extremities both the next heart beat so would only supply blood to areas close to the heart therefore larger animals need larger hearts so they can pump a larger amount of blood with each beat. We see an example of this when people are administered adrenalin for a long period of time after toxic shock, the heart is too fast for the blood to reach the extremities and the tips of the noses and fingers go black as a result
2006-10-10 22:51:25 · answer #3 · answered by blue_cabbage 2 · 0⤊ 0⤋
Large animals have a larger heart and a slower heartbeat
because of the vast amount of blood that needs to circulate
over a much longer and larger general system.
Also, they need more time for the larger lungs to generate
the required oxygen for them to live normally, So if they had
a faster heartbeat they would run out of oxygen and faint.
Also, the larger the animal, the lower the body temperature.
2006-10-11 03:37:55 · answer #4 · answered by Ricky 6 · 0⤊ 0⤋
It is the same in humans as well. Babies and children have faster heartrates than adults do.
It is because the stroke volume of little hearts are smaller than that of bigger hearts. Stroke volume is the amount of blood pumped each heart beat that is a formula of rate vs. strength of heart beat or contraction. In small hearts there isn't an ability to pump a larger volume of blood without increasing the rate because there is less heart muscle. In larger hearts, the heart can pump harder and faster because of the extra muscle. Because of the extra muscle it gets more blood to move with a stronger contraction, leading to a slower heartbeat.
Does that help?
2006-10-10 22:56:47 · answer #5 · answered by tallnfriendlyone 3 · 0⤊ 0⤋
This is because every time the heart beat (heart rate) the blood is pumped into the arteries, therefore because the bigger animal has a larger body it will take longer than the small animal.
2006-10-12 02:06:15 · answer #6 · answered by miz nick 2 · 0⤊ 0⤋
Other people have already answered your question about size and heart rates, but I just wanted to point out that there is no hard and fast relationship between size and lifespan - there's a general trend for larger animals to live longer, but bats and rats are roughly the same size and have similar metabolic rates but vastly different lifespans...it's not just about how many times your heart can beat.
2006-10-11 00:32:00 · answer #7 · answered by lauriekins 5 · 0⤊ 0⤋
The warranty for the average animal heart is for 2.5 billion beats.
It takes a human about 70 years to get there.
2006-10-10 22:55:10 · answer #8 · answered by Anonymous · 0⤊ 0⤋
it takes more energy for the heart to pump the blood around a large animals body, there for slower heart rate.
2006-10-10 22:45:42 · answer #9 · answered by angel 4 · 0⤊ 0⤋
Large hearts have a bigger capacity for pumping the blood. Smaller ones have to work harder.
2006-10-10 22:47:52 · answer #10 · answered by Anonymous · 0⤊ 0⤋