What is the heart rate of a mouse, an elephant or a blue whale? Find out here about these and other curiosities about the heart of the animals (...and humans).

What is the heart rate of a mouse, an elephant or a blue whale? Find out here about these and other curiosities about the heart of the animals (...and humans).

0.8 seconds. A human heart takes 0.8 seconds to complete a cardiac cycle. 0.27 seconds are invested in the systole and 0.57 seconds in the diastole. A mouse completes a cardiac cycle in 0.09 seconds.

1 extra valve. Crocodiles have a unique type of valve in their hearts. This valve is situated in the right ventricle, and can divert blood going to the lungs back into the body, a phenomenon known as a shunt.

2 times bigger. Pythons and other reptiles double the sizes of their hearts (and other organs) after breaking a prolonged fast.

3 hearts. Octopuses have three hearts. Two brachial hearts on either side of the body oxygenate blood by pumping it through the gills. The systemic heart in the center of the body pumps oxygenated blood from the gills through the rest of the organism.

4 chambers. Only mammals, birds and crocodilians have anatomically separate ventricles. This allows the complete separation of systemic and pulmonary circulations. Other vertebrates have only one ventricle.

8 bpm. Bears have heart rates of about 40 bmp. During hibernation it is reduced to 8 bpm.

12 kg. A giraffe depends on it’s powerful heart that weights up to 12kg so that it can fight the force of gravity up that long neck to the head.

16 days. The human heart is believed to start beating 16 days after conception. This was extrapolated from mice, on which heart starts beating 7.5 days after conception. In pigeons, the heart starts beating at day 3.

20 percent. Zebrafish can regenerate its heart. In just two months, the heart is fully regenerated after 20% of the muscle is damaged.

60 percent. Of all human proteins (n=19692), 60% are expressed in the heart at some point. 248 of these genes are highly expressed in heart compared to other tissue types.

72 bpm. The average heart rate for a man is 72bpm. A blue whale’s heart beats six times a minute. A horse has 38bpm. A rabbit has 205bpm. A rat 420. A mouse 670. The heartbeat of a canary occurs 17 times in a second.

250 bpm. The heart rate of a cheetah increases from 120 bpm at rest to 250 bpm after a chase. This allows the cheetah to sprint at around 100 km/hr. Sprint rates can only be sustained for about 200-300 meters.

280/180 mmHg. A giraffe’s blood pressure is the highest of any mammal: 280/180 mm mercury. They also have a valve system running the length of their neck to ensure blood reaches their head efficiently. Normal humans blood pressure is 120/80 mmHg.

500 kg. The heart of a blue whale weighs about a half a ton, 1000 lbs. It has to be large enough to pump about 15,000 pints of blood as compared to about 8 pints in a human.

750 bpm. Short-tailed shrews have recorded heart rates of 750 bpm at rest (and 168 breaths). With the highest surface area relative to body mass of all mammals, their body temperature soon dissipates into the air. Metabolic needs to maintain body temperature, require shrews to eat their approximate weight every day.

1260 bpm. A rate of 1260 beats per minute was measured in a Blue-throated Hummingbird. In torpid hummingbirds, the heart rate can drop to 50-180 per minute.

2-3 billion cardiomyocytes. The human heart contains an estimated number of cardiomyocytes of 2-3 billion.

3 billion heartbeats. At a rate of 72 bmp, a human heart beats approximately 3 billion times on an 80-year lifespan.



