What is a common characteristic of the eyes of poisonous snakes?

The characteristic of poisonous snakes is the presence of elliptical pupils. This adaptation is particularly beneficial for these reptiles, as elliptical pupils enhance their ability to judge distances and improve their vision in low-light conditions. This feature allows them to effectively hunt and avoid predators, especially since many venomous snakes are ambush hunters that rely on stealth.

In contrast, many non-venomous snakes tend to have round pupils, which do not provide the same advantages in dimly lit environments. Rectangular and square pupils do not typically appear in snakes and are not recognized as standard formations in this group. Therefore, the structure of the pupils can be an important visual cue for identifying snake species and understanding their ecological adaptations.