Happy EleFACT Friday. Although elephants’ physical size towers over many other species, the internal organs are proportionally no bigger than those of many other mammals. However, the heart in particular is surprisingly large and can vary in size depending on the elephant’s age and weight. The average weight for an elephant heart is about 12 to 21 kg (26.5- 46.3 lbs.) and comprises about 0.5% of the animal’s total body weight. Comparatively, an adult human heart only weighs about 310 grams, and is the size of a clenched fist.
In terms of heart rate, elephants are actually on the lower end of the spectrum. To hear an adult elephant’s heart rate, an EKG or other amplification methods must be used as opposed to a normal stethoscope. Their hearts beat around 30 times per minute, compared to the human resting heart rate of about 60-100 bpm. Elephants have a significantly higher average blood pressure (about 180mmHg) to keep their much larger vessels open. To counter this, elephants have notably lower resting heart rates.
Generally, most mammals’ heart rates slow down when resting or sleeping. The elephant is also unique in this way, with a heart rate that actually speeds up when they are lying down. This is because when lying or resting, the weight of their body reduces their lung capacity — leading to both the heart rate and blood pressure increasing.
Photo of Mara