Reptile Research and Studies

Reptile research and studies have been limited compared to mammals, but are increasing. This includes studies of cognitive ability, such as flavour aversion learning, and studies of behaviour, such as how green iguanas respond to handling.


Eight different aspects of sentience are assumed in the scientific literature; anxiety, distress, excitement, fear, frustration, pain and suffering. The results of these studies are important for animal welfare.


Reptiles can be difficult to study as they live mainly in natural habitats, often in remote locations that are difficult for researchers to access. Therefore, collecting them can be time-consuming and expensive.

To help reduce costs, many researchers use a reversible procedure called surgical celiotomy, which provides access to most internal organs. This technique is simplest to perform in lizards, where the uncompartmentalized coelom allows easy visualization, more difficult in snakes with diffuse fat bodies, and hardest in crocodiles and chelonians, which have bony integuments and compartmentalized coelomic cavities. For this reason, modern rapid absorbable sutures (for example, polyglactin 910) and monofilament nylon are favored. Surgical lights that are easily focused and powerful enough to provide adequate magnification for these small patients are also important.

It is hoped that future research into reptile sentience will focus more on their emotional and cognitive abilities, so that they are seen alongside mammalian species as thinking, feeling beings who suffer from poor treatment. Demonstrating their complex capacities for suffering may be an effective way of engendering a better public perception of these often-maligned animals, as well as improving the quality of life they experience in captivity.


The reptile research community has produced a large quantity of high-quality scientific literature, including detailed descriptions of many species. Most of the 10,531 reptiles assessed in this review are squamates (snakes and lizards) but there is a fair number (348) of chelonians as well (turtles, terrapins and tortoises).

Although the research community has made significant progress in understanding the biology of these species, gaps remain, especially for some regions, taxa and life-history traits. For example, a substantial proportion of reptiles (particularly turtles and crocodilians) are adapted to cool waters; thus, any change in water availability may impact their survival. Similarly, changes in climate will affect the thermal niches of some reptiles; cool temperatures may reduce activity windows and increase mortality rates, while warmer temperatures could alter boom-bust reproduction cycles or cohort survival.

There is increasing recognition that reptiles are sentient, capable of experiencing pain, stress and fear. Such findings are likely to change perspectives towards these animals and improve their welfare in captivity, where they are often mistreated or killed for the exotic pet trade.

There are also implications for conservation. For example, the behavioural responses of goannas and blue-tongue skinks to eating cane toad sausages laced with nausea-inducing chemicals demonstrate that these creatures are able to learn from their experiences; this information can help to guide future decisions that will reduce the threat posed by this invasive predator.


Reptiles are a diverse group of vertebrates, distinguished by their unique external appearance. Their skin – usually either scales or bony plates – enables them to adapt to their environment and provides protection from predators. Unlike mammals, reptiles are ectothermic, meaning their internal body temperature depends on the ambient environment. They also lack a central nervous system, making them more sensitive to changes in their surroundings.

The evidence that reptiles are capable of feeling pain, anxiety and stress has implications for their welfare in captivity. The vast majority of reptiles sold for the exotic pet industry live in conditions that are a far cry from those they would experience in the wild, and are often subjected to misguided husbandry practices that fail to meet their animal welfare needs. Recognising the capacity of reptiles to feel emotion and suffering will help to change perceptions of these species, challenging the notion that they are unintelligent and insensitive.

A number of keywords were used in this review that returned few results. These were ‘pain’, ‘stress’, ‘anxiety’ and ‘fear’. However, there is some evidence that these terms have a specific meaning in the context of reptiles; for example, studies examining an increase in heart rate during simulated handling may be interpreted as an indication of emotional stress. Other keywords that failed to return any results were ‘play’ and ‘interaction’, though there is evidence of these behaviours in reptiles (for instance, when crocodiles play with pink flowers). The absence of these keywords suggests that further research is needed into the nature and significance of these behaviours.


Reptiles are popular pets worldwide, with the trade in exotic animals likely to involve tens of millions of creatures (many of which may be illegally wild-caught). Research that highlights their complex needs can help to promote more appropriate captive conditions and improve animal welfare. In particular, research that showcases their cognitive and emotional abilities can serve to dispel the myth that they are unfeeling automatons and to change perspectives towards their welfare needs.

The majority of bacterial infections in reptiles are caused by gram-negative bacteria (Pseudomonas, Aeromonas, Citrobacter, and Klebsiella) and can have high levels of sensitivity to antibacterial drugs. For this reason, samples for Gram stain, cytology, culture, and antibiotic sensitivity testing should be obtained prior to starting antibiotic therapy.

Ultrasound examination is a useful adjunct to radiography in many reptile species, especially for examining the coelom (for suspected impactions or foreign bodies), the gastrointestinal tract, liver and gallbladder, and soft-tissue masses. A 10- to 20-MHz probe is most commonly used. For some species, transillumination using a cold light source is also useful for visualizing internal structures.

Research into the capacities of reptiles to feel pain, stress, and fear is critical for improving their welfare in captivity. This type of research can be used to promote more appropriate captive conditions and also highlight any inadequacies of existing legislation and the associated exotic pet industry.