Reptiles’ Emotional and Cognitive Abilities

Research into reptiles’ emotional and cognitive abilities is growing, but this must be communicated to the public. This information could help to position these animals alongside the more popular mammals, and to demonstrate that they suffer, too.


The eight key words returning results from the search included pain, anxiety, stress, frustration and fear. The following articles explore these themes.

Human-Reptile Conflicts

Reptiles are susceptible to human-induced threats, including habitat degradation, climate change, disease, illegal trade and pet keeping. Consequently, their conservation requires a multidisciplinary approach to address these threats. Fortunately, modern approaches for reptile conservation include conservation translocations, regulations on the international trade in reptiles, management of imperiled species in landscapes, and progress in confronting emerging diseases.

Despite these advances, a number of major gaps persist in our understanding of reptiles and humans. For example, many reptile species have outdated threat assessments based on data collected decades ago and may be underestimating current risk of extinction. Similarly, the widespread threat of free-roaming domestic dogs has led to a decline in desert tortoise (Tertius occidentalis) populations.

Studies of human attitudes toward reptiles are often unbalanced, with a heavy focus on snake fears and phobias. This bias should be addressed in future research by expanding studies to include multiple taxonomic groups, e.g., lizards and crocodiles. Likewise, more emphasis should be placed on evaluating human-reptile conflicts and wildlife management, which are less common topics of study.

The majority of human-reptile conflicts involve snakes and freshwater turtles. These cases are often reported to animal control agencies, which mediate the conflict. A recent study analysed callouts made to the Environmental Police in Belo Horizonte, Brazil, over a 7-year period, and found that the presence of snakes or freshwater turtles influenced the decision to call out the authorities for animal control. In addition, the callout distribution was correlated with a number of socio-economic characteristics of the city residents.

Habitat Degradation

Amphibian and reptile studies have often been constrained by the availability of suitable habitat. For example, the tinajas (bedrock pools) of lowland leopard frogs have been filled in or covered by sediment as land is developed around them. Similarly, the shallow waters of arid stream systems may be drained or lost due to anthropogenic activities. Moreover, reptiles have small distributional ranges with high endemism and consequently are vulnerable to habitat degradation (Todd et al. 2010).

As the global biodiversity crisis intensifies1, comprehensive extinction risk assessments are increasingly being applied across all taxonomic groups. These are essential for the calculation of species threat abatement and restoration metrics2, identification of key biodiversity areas3, and resource allocation using systematic conservation planning4-5. However, until recently, reptiles have been omitted from these assessments. This is despite the fact that, like all tetrapods, reptiles are facing an unprecedented rate of extinction threats6,7.

The latest IUCN Red List assessment of all reptiles finds 1,829 species (21.1%) to be threatened. The squamate reptiles (including lizards and snakes) are the most speciose group in this category, followed by crocodiles and turtles and finally tuatara (Rhynchocephalia). This is the highest proportion of threatened species among all tetrapod groups, surpassing amphibians and birds. The underlying drivers of this increase in reptiles’ extinction risk are largely human-mediated: habitat loss, land transformation and climate change6,8. Climate change is a particularly threatening factor, affecting reptiles by reducing thermally viable windows for foraging, skewing offspring sex ratios of reptiles with temperature-dependent sex determination, and contracting their ranges9.


Reptiles are susceptible to a wide range of illnesses. They often suffer from the same problems as other animals: overcrowding, improper nutrition, uncontrolled breeding, inadequate temperatures and humidity, poor handling, transportation, parasites, and exposure to toxins.

Pneumonia is one of the most common reptilian illnesses. It is most frequently caused by opportunistic gram negative bacteria like Pseudomonas and Aeromonas. These bacteria are more likely to occur in poorly maintained and malnourished snakes and lizards. Pneumonia can be life threatening for some species. The treatment for pneumonia includes antibiotics and supportive care.

Ranaviruses have been shown to be important pathogens of ectothermic reptiles. They have been identified in chelonian species such as Russian tortoises (Testudo horsfieldii), Eastern box turtles (Terrapene carolina), Chinese softshell turtles, Hermann’s tortoises, and leopard tortoises. They are most commonly associated with gastrointestinal tract lesions, and have also been detected in the skin of saltwater crocodiles (Crocodylus porosus) with crusty ulcers on the abdomen.

Focal infections can occur due to traumatic injuries, bite wounds, or subcutaneous abscesses. Bacterial isolates of the anaerobic organism Peptostreptococcus, and of the aerobes Pseudomonas, Aeromonas, Salmonella, and Escherichia coli have been found in reptilian abscesses. Intensive supportive care is often required. Recognizing that reptiles are sentient and capable of feeling pain, stress, and fear is vital in changing perspectives towards their welfare needs. It can also help to improve regulations and associated exotic pet industry practices.

Model Organisms

A model organism is a nonhuman species that scientists study to learn more about biological processes in the hopes that those discoveries will ultimately be applicable to human health and disease. Model organisms are typically easy to breed and maintain in the laboratory, making them convenient for experimental research. They also frequently occupy pivotal positions in the evolutionary tree, giving scientists insight into evolutionary development.

While anything could be a model organism in theory, most biomedical and biological research is done using only a few species. For example, cancer biologists often work with mice, while neuroscientists use mice and rats. And geneticists often turn to the fruit fly Drosophila melanogaster, the zebrafish Danio rerio or the nematode worm Caenorhabditis elegans to understand basic genetic processes.

Scientists often choose these models because of their many experimental advantages, including short generation times and the fact that they are highly amenable to genetic manipulation. They are also comparatively close to humans in terms of evolutionary distance, which can be useful for understanding how human biology works.

However, some critics have argued that the concept of “model organism” is a limiting one for contemporary biology and that it may discourage research on other species. Indeed, some scientists have begun to abandon the standard models in favor of more diverse systems. For example, some have embraced the planarian flatworm S. mediterranea as a new model to explore regeneration.