Heart disease in lizards

The heart is a muscle which collects blood full of oxygen from the lungs and pumps it around the body. It also collects blood full of carbon dioxide from the body and pumps it back to the lungs. This cycle goes on continuously.

In mammals the heart sits in the chest cavity and is divided into four chambers. The right atrium collects blood full of carbon dioxide from the body, sends it down to the right ventricle which then pumps it to the lungs. The left atrium collects blood full of oxygen from the lungs, sends it down to the left ventricle which pumps it around the body. Blood is constantly being pumped from right to left, via the lungs and travels around the body inside a series of tubes of varying diameters; these are known as blood vessels.

The heart of a lizard differs from that of a mammal in several ways. It is specially adapted to suit the life of a reptile. In small lizards, the heart sits forward in the chest, between the front legs; in larger lizards, like the Monitor, it sits further back in the chest. Inside the heart of the lizard there are three chambers; these are the right atrium, left atrium and the ventricle. There is also an extra chamber outside the heart called the sinus venosus which collects blood.

Lizards can move blood to wherever it is needed in the body. Remember how the mammal heart always pumps blood round the body from right to left? Lizards can change the direction of the blood so that it can flow backwards. This is one of the ways that lizards can survive if they are short of oxygen or if they become dehydrated.

It is essential to ensure your lizard’s housing is maintained at the correct temperature which differs depending on the species of lizard; if it is too cold, its heart cannot beat fast enough to keep the blood pumping to all the vital organs.

It is also vital to provide a good source of UV light and a balanced diet. The heart is a muscle and needs a constant supply of calcium to enable it to beat properly.

Luckily, heart disease is not commonly diagnosed in lizards.

Heart disease is not commonly diagnosed in lizards.

There is a condition where the dew lap becomes full of fluid in bearded dragons, and this is thought to be a clinical sign of heart failure.

Maintaining good nutrition, temperature and housing can all help further in minimizing the risk of any problems developing.