Poikilotherms are an animal whose internal temperature varies considerably. Fishes (like Labeo, Torpedo, Pristis, Carcharodon, Scoliodon, Trygon), Amphibians (Rana) and Reptiles (Naja) are poikilotherms but Pteropus (mammal) is a homeotherm or endotherms or warm-blooded animals.