Rays are ectothermic, meaning that their body temperature is controlled by the environment around them. Little is known about the endothermic process in rays. A research study was done in 2017 to tag 50 rays at both Marker Bar and the Schooner Caysat Newcastle University, but there was never a follow up with the results.

Osmoregulation describes the way marine animals maintain the concentration of water in their bodies. Rays maintain osmotic concentration of blood at the same level as that of their surrounding environment, yet they are not in danger of dehydration. This is done by retaining nitrogen-containing compounds, mainly urea and trimethylamine oxide, in their blood. Their kidneys have large glomeruli and urine is formed by filtration, however, most of the filtered urea is reabsorbed by special segments of the urinary tubule.

The Endocrine System is one of two systems that communicates information from one cell to another, the other being the nervous system. The Endocrine System consists of all organs and tissues that produce hormones. This includes but is not limited to the thyroid, hypothalamus, pituitary, and adrenal glands.