The D'Arsay are referenced in a STO mission. In there, you have to scan their graves and find out the were pokliothermic, i.e. amphibian. That's why they revere the sun so much.
The word is poikilothermic, and it refers to an organism whose body temperature is variable (i.e. what's inaccurately called a "cold-blooded" creature in vernacular). Amphibians are poikilotherms, but so are fish, reptiles, many invertebrates, and even naked mole rats (the only known mammalian ones).