A Shared Vertebrate Plan
Reptiles have a central nervous system made up of the brain and spinal cord, together with peripheral nerves that carry information to and from the body. This broad arrangement is shared with other vertebrates, but its proportions and specialisations differ among turtles, crocodilians, lizards, snakes and tuatara. Nervous tissue coordinates movement, feeding, reproduction and responses to changing conditions rather than acting as a single, uniform system.
Sensory Systems Fit the Species
Vision, hearing, touch, chemical sensing and temperature sensing are important in different combinations. Snakes and many lizards use the tongue to transfer chemical particles to the vomeronasal organ. Pit organs detect infrared radiation in some snakes, including pit vipers and some boas and pythons, but they are not a feature of all snakes. A sensory ability is useful only in the ecological context in which it evolved.
Automatic and Learned Responses
Neural pathways also help regulate breathing, circulation and digestion without constant conscious control. Reptiles can learn associations and adjust behaviour, although the best tests depend on the species and the question being asked. Comparing a reptile brain directly with a mammal brain can hide those differences. It is more useful to ask how a particular animal detects information, makes choices and responds in its own habitat.
