Reptile behavior is not as well studied as many other vertebrates, but there is some good information available. [1]
Some lizards such as Asian rat snakes flatten their bodies and cranial areas to increase size in defense displays, distracting the attacker enough for escape. They also wiggle their tails to divert attacks from the vulnerable head.
Defensive Behavior
Reptiles exhibit a wide range of defensive behaviors in response to immediate threats. These include fight, flight and hiding. Generally, inanimate environmental threat sources elicit few defenses and animate threats such as predators or conspecific attack provoke a more complex defensive repertoire.
Most species of reptile have evolved structures and behaviors that promote defense. For example, some have powerful crushing jaws with sharp teeth (crocodiles) or a venom gland that produces poisonous fluids (snakes). Others have cryptic coloration and body structure which can blend in with their environment (turtles).
A study of the behavior of Leopard Geckos reveals that if a threat is perceived they may display a variety of behavioral defenses such as hissing and tail waving. If a threat continues it is possible for the gecko to drop its tail and begin to spasm and twitch, an action known as Caudal Autotomy. The aim of this display is to distract the predator whilst the reptile escapes.
Studies have shown that defensive responses are continuously reorganized during ontogeny. This is largely the result of learning; direct interactions with threatening stimuli influence subsequent responses and the resulting changes represent another type of plasticity in behavioral expression. In particular, maturation of the components and connections of the fear circuit appear to contribute to these changes. This process may be enhanced by maternal care and learning.
Social Behavior
Reptiles have long been portrayed as loners, but in fact many species live in groups. They often communicate, eat, hunt, migrate, court, mate, nest and hatch together. In their new book, Doody and his coauthors describe decades of research from around the world that details the mysterious social lives of reptiles.
For example, it is well-known that some squamate reptiles form family units based on delayed natal dispersal and extended parent-offspring associations that last several years. These associations are supported by shared crevice use, communal scat deposition and regular physical contact among group members. Interestingly, these familial interactions are often less hierarchical than those observed in mammals or birds and have a more discrete phylogenetic distribution than is seen in lizards.
A number of aquatic reptiles, including freshwater turtles and worm lizards, have also evolved social systems that are comparable to those found in mammals and birds. It is also known that some squamate reptiles can recognize conspecifics through their chemical scent, which allows them to avoid intruders and maintain social associations.
In addition, some squamate reptiles exhibit social buffering behavior, the ability to protect their young from predators or prey. A famous example of this is the way in which male crocodiles protect and care for hundreds, even thousands of babies that aren’t their own. This is a highly unusual form of social behavior and it’s not yet clear why it has evolved in crocodiles.
Food Preparation
Reptiles eat a wide range of animal food including fish, birds, mammals, frogs, insects, sea creatures and other reptiles. Many reptiles, especially herbivorous ones, hunt and forage for their food to ensure they are getting all the vitamins, minerals and nutrients that they need to be healthy. Depending on the species, they may also eat prepared foods like pellets or powdered meals such as crickets and mealworms.
Herbivorous species (green iguanas, bearded dragons, many skinks, box turtles and semi-aquatic turtles) should be fed fresh leafy greens, vegetables and/or fruits daily. Vegetables should include collard or mustard greens, kale, beets, kohlrabi, turnips, rutabaga, radish and zucchini, plus some non-citrus fruit. A small amount of canned cat or dog food can be included to add variety to the diet and help provide a complete diet for these reptiles.
When these reptiles are threatened or manipulated they may display a “fluff-up” defensive posture that is similar to the coiled up posture exhibited by snakes suffering from parasitic, viral or fungal central nervous system disease. This behavior can serve as an early warning to the caretaker or veterinary practitioner to look for and treat any illness that has occurred.
All reptiles should be handled regularly in a low stress manner to help them become accustomed to human touch and interaction. By understanding normal and abnormal reptile behavior, the veterinary practitioner can better educate and counsel clients to assist in the proper care of their pets.
Communication
Reptiles display a remarkable diversity of visual, auditory and (sometimes) chemical communication. Their social behavior parallels and often surpasses that of many mammals and birds and their complex courtship, parental care, mating rituals and hunting strategies are amazing to witness.
Many of these behaviors can be misinterpreted by novice reptile owners as disease or trauma. For example, some reptiles will begin morning basking by exposing only their head from a crevice or burrow in order to increase heat uptake by hormonally controlled darkening of the skin. This is a normal strategy but when seen in a pet reptile can be interpreted as signs of respiratory disease or other pathology. Similarly, some lizards exhibit physical gestures of thermoregulation such as pushing up on one hind leg and raising the opposite foreleg at the same time while balancing on the other two legs. This is also a form of visual communication that may resolve duels or negative interactions between individuals before they turn violent.
Other reptiles produce sounds as warnings to predators or to communicate with conspecifics in territorial disputes. Snakes such as rattlesnakes, hognose snakes and cottonmouth water moccasins produce telltale rattles to warn of danger. Many lizard species display head bobbing as a means of communicating to other lizards or to settle disputes over territory or agonistic relationships.