Reptiles are a diverse group of animals, with a range of habitats and social behaviors. The study of these animals is called Herpetology.
게코도마뱀The capacity for reptiles to feel pain, stress and anxiety is well accepted in the scientific literature. However, despite this, indicative behaviours can often be overlooked by those who care for reptiles in captivity.
Physiology
Reptiles have a much wider range of behavioral responses to environmental stimuli than many people realise. They are not as sedentary as some would claim and their natural home ranges can be quite extensive. In captivity, however, they may be restricted in the space they have available to them and can often suffer from misguided husbandry that fails to provide for basic animal welfare needs.
There are also a number of myths about reptiles that lead to the incorrect assumption that they do not feel pain or that they do not have a sophisticated immune system, which is untrue for most species. They do have a sensitive immune system but it is primarily temperature dependent and functions best when in its preferred optimum temperature zone. When kept outside of this zone they are more susceptible to infection from a wide variety of pathogens, including some bacteria that can cause gastrointestinal disease.
All snakes, lizards and chelonia have a three-chambered heart (2 atria and 1 ventricle) whereas crocodilians have a four-chambered heart (3 atria and 4 ventricles). In non-crocodilian reptiles, functional separation of venous and arterial blood is achieved by a muscular ridge in the ventricle, known as the intraventricular septum. Heart rates are dependent upon body size, metabolic rate, apnea and sensory stimulation. Evidence has shown that reptiles can experience stress, pain and fear, which is important in highlighting their sentience and highlighting the potential impact of misguided care in captivity.
Genetics
Reptiles are among the least studied animals in captivity. Despite this, there is increasing interest in studying the behavior and genetics of these animals. There is also a growing awareness of the need to address reptile welfare issues, particularly in relation to the exotic pet trade.
Reptilian genetics research is focused on understanding the evolution of reptile species and identifying key genetic markers that can be used in population monitoring. There is also a focus on the genetics of individual reptiles and their relationships to other reptiles and humans.
Genetic studies of reptiles are complex, and it is important that herpetological geneticists have a solid background in both evolutionary biology and molecular genetics before beginning any genetic studies of reptiles. The classification and known diversity of reptiles is in a state of flux, as new species are discovered or identified and existing taxonomic boundaries may be revised based on phylogenetic analysis. This flux has been accelerated by increased emphasis on biotic surveys and advances in technology, including DNA sequencing and genome mapping.
While research on reptiles’ capacity to experience fear, stress, pain and suffering is ongoing, the science of animal sentience remains a relatively young field of study. Nonetheless, this review found that eight different sentience traits/aspects were assumed to exist in reptiles in the literature reviewed; anxiety, distress, excitement, fear, frustration, pain, and suffering.
Behavior
Reptiles have evolved a variety of fascinating strategies to help them survive and thrive. One of the most notable is camouflage, which helps them blend seamlessly into their surroundings, making it difficult for predators to spot them. Another survival trick is slow metabolism, which allows them to withstand periods of low food availability longer than mammals can.
Like many other animal groups, reptiles play an important role in their habitats. From pest control to nutrient cycling, they contribute in a variety of ways. They also serve as prey and/or predator, maintaining balance in their respective food webs, and helping to regulate temperature.
Because they are ectothermic (they depend on external sources of heat to regulate their body temperature), reptiles must often seek shelter to escape from rising temperatures. However, the rise in global temperatures has seen reptiles retreating to their shelters more often, resulting in reduced activity and decreased exercise, which can have a detrimental impact on health.
Unlike the popular perception of reptiles as unthinking, unfeeling creatures, recent research suggests that they do indeed feel and experience emotions. While it is acknowledged that reptiles do not have the cognitive abilities to suffer, their capacity to feel fear, anxiety, stress, and pain is recognised and has implications for their welfare in captivity.
As a result of the high levels of interest in reptiles, more research is being undertaken on reptiles than ever before. Nevertheless, factors such as size, type of habitat, threat of extinction, proximity to research institutions, and national income influence which reptile species are studied more than others.
Conservation
As stewards of one of the world’s largest reptile collections, Academy scientists are committed to understanding which reptile species live where and how they’re related so we can help protect them. This research includes addressing a number of key questions, such as how many reptiles are left in the wild and what their conservation status is, the impact of human development on their habitats and whether they experience suffering.
As with amphibians and birds, reptiles are threatened by global anthropogenic pressures such as habitat loss, overharvesting, and the spread of invasive species. The extinction risk of reptiles is high, with 474 threatened species, including turtles, crocodiles, lizards and snakes, and the New Zealand tuatara—the only living member of a lineage that evolved in the Triassic period 200 million to 250 million years ago.
Reptile conservation efforts need to be just as comprehensive as those directed at other animal groups. This will involve reducing human impacts on their habitats through a range of activities, from habitat restoration and creating head-start programs to changing livestock grazing practices and adding woody debris to the landscape to reduce herbivore foraging.
It will also involve ensuring that those who care for captive reptiles understand the capacity of these animals to feel pain and distress, which can be ignored or misinterpreted as normal behaviour, perhaps due to long-held perceptions of their ‘lower status’ or because their behavioural responses to stress are atypical. For example, shivering may be a sign of pain in snakes and anorexic behaviours in lizards can be taken as signs of agitation.