A typical snake’s heart has three chambers: two atria and one ventricle.
The ventricle is partly divided by an incomplete muscular septum, allowing snakes to separate some oxygen-rich and oxygen-poor blood. This arrangement is common among non-crocodilian reptiles and differs from the four-chambered heart found in birds and mammals.
Snake hearts are also unusually mobile. The heart can move within the body cavity as food passes through the oesophagus, reducing the risk of injury during swallowing. Its position varies among species, but it is generally found in the front portion of the body.
A three-chambered heart does not mean snakes have poor circulation. Their circulatory system supports active lifestyles, including rapid movement, swimming and prolonged digestion after a large meal.