The heart is the engine of life, and its rate varies greatly among species. From tiny rats to majestic elephants, heart rate is related to the size, metabolism and longevity of each animal. In general, smaller animals have hearts that beat much faster than those of larger animals.
Approximate heart rates of different animals.
- Human: 60 – 100 beats per minute (at rest).
- Rat: 300 – 500 beats per minute.
- Mouse: 500 – 700 beats per minute.
- Fly: about 200 – 400 beats per minute (their circulatory system is different, but this range is estimated at rest).
- Wasp: 300 – 400 beats per minute (similar to other insects of similar size).
- Cat: 140 – 220 beats per minute.
- Dog (depending on size):
- Small breeds: 100 – 160 beats per minute.
- Large breeds: 60 – 100 beats per minute.
- Rabbit: 130 – 325 beats per minute.
- Guinea pig: 230 – 380 beats per minute.
- Lion: 40 – 50 beats per minute.
- Tiger: 50 – 70 beats per minute.
- Horse: 28 – 44 beats per minute.
- Cow: 48 – 84 beats per minute.
- Sheep: 70 – 80 beats per minute.
- Elephant: 25 – 35 beats per minute.
- Giraffe: 40 – 90 beats per minute.
- Blue whale: 8 – 20 beats per minute.
- Dolphin: 35 – 60 beats per minute.
- Hummingbird: 500 – 1,200 beats per minute.
- Hen: 250 – 300 beats per minute.
- Ostrich: 60 – 70 beats per minute.
- Gorilla: 70 – 90 beats per minute.
- Crocodile: 24 – 30 beats per minute (may slow down a lot under water).
- Giant tortoise: 6 – 20 beats per minute.
Why do the smallest ones beat faster?
Small animals, such as rodents or tiny birds, have a fast metabolism: they need to burn energy quickly to survive. That’s why their hearts beat at full speed. In contrast, huge animals such as elephants or whales have slower metabolisms, and their hearts beat very slowly.
The case of the human being.
Humans are somewhere in between. Our resting heart rate is between 60 and 100 beats per minute, although elite athletes can have less than 50, thanks to cardiovascular training.
Conclusion.
Heart rate reveals much more than the size of the heart: it tells about the metabolism, lifestyle and even the life expectancy of each species. The smaller ones live fast and with hearts that don’t stop, while the giants beat calmly… and tend to live longer.
