Lizards are quite unique in the fact that they
are cold-blooded. Lizards need to regulate their body
temperature through their external environment, as they
do not have the biological means to do so internally.
This is why you need to supply basking spots and ranges
of temperatures when keeping pet lizards.
The lizard circulatory system is very interesting.
Lizards have a three-chambered heart. Their heart consists
of two aortas, two atria and a variably partitioned
ventricle. Their heart mixes oxygenated and deoxygenated
blood, the degree of which varies from species to species
and by their current physiological state.
The ventricles in a lizards heart share oxygen
back and forth in a constant exchange, but the division
of the ventricles vary. However, the hearts atrium is
always separated into two chambers; left and right.
Their heart allows for the redirection of blood to the
body or the lungs allowing for better thermoregulation.