The rete mirabile allows for an increase in muscle temperature in regions where this network of vein and arteries is found. The fish is able to thermoregulate certain areas of its body. Additionally, this increase in temperature leads to an increase in basal metabolic temperature.

How does a rete work?

The rete creates a high oxygen partial pressure for diffusion to meet the high metabolic demand of the avascular retina. In most other vertebrates, the retina is well vascularized with an abundant supply of capillaries to deliver oxygen to the metabolically active tissue.

What is meant by rete mirabile?

: a small but dense network of blood vessels formed by the breaking up of a larger vessel into branches that usually reunite into one trunk and believed especially important as an oxygen-storing mechanism in aquatic mammals.