Why are reptiles usually found only in warm, tropical seas?

Reptiles are classified as cold-blooded, or ectothermic, creatures, which means that their body temperature is largely determined by the environment in which they live. This characteristic significantly influences their habitat preferences. In warm, tropical seas, the temperatures are conducive to maintaining their body heat, allowing them to be more active and efficient in hunting and reproduction. Cold-blooded animals rely on external heat sources to regulate their body temperature, so they thrive in warmer environments where they can easily attain the necessary warmth for their physiological functions.

In contrast, in cooler waters, reptiles may find it difficult to maintain an optimal body temperature, impacting their metabolism and activity levels. This explains their preference for the warmer, tropical regions where the environmental conditions support their survival and reproductive needs, making them more prevalent in these areas.