This image is a graph where the vertical axis is labelled with heart rate in beats per minute (bpm) on a logarithmic scale, starting at zero bpm running through values of 20bpm, 50 bpm, 100 bpm, 200 bpm, 500 bpm and 1,000 bpm. The horizontal axis is labelled with life expectancy in terms of years on a linear scale, starting at zero years running through values from 10 years to 90 years in units of 10 years. Various animals are labelled on this graph; starting from the top left with a mouse (500 bpm, less than 10 years) next to a hamster and rat with similar values; then a marmot and monkey (200 bpm, 20 years); then a cat and dog (100-200 bpm, 30 years); then a giraffe, tiger and ass (50-100 bpm, 30-40 years); then a horse, lion and elephant (30-50 bpm, 55-60 years); then a whale (20 bpm, 60 years); finally a human (100 bpm, 80 years). A line of negative gradient is drawn from the mouse to the whale indicating a correlation between the faster the bpm the shorter the life expectancy or conversely, the shorter the bpm, the longer the life expectancy.