Animal Information

A Little STRESS Goes a LONG Way in MOST Reptiles

We had a turtle pass away recently and it inspired us to learn more about the natural behaviors of turtles when it comes to stress. This page is dedicated to Mr. Beans. He was a Mississippi Map Turtle who was brought here after its cage mate began combating with him. Beans was not here very long but he is very much missed. RIP Mr. Beans.

We have long heard that a simple move can be too much for reptiles. Especially turtles and tortoises. Was being rehomed enough to cause Mr. Beans to pass away? While we will never really know, there is also the idea he may have been born with MBD as he was very small for his species age. Can it be both? Having a medical condition combined with a stressful situation?

Chelonians are not commonly seen in general veterinary practice because illness, stress, distress, and pain can be very difficult to observe or measure in this group of reptiles. As ectotherms, they are reliant on the captive environment for the establishment of suitable conditions to maintain good health and wellbeing. 

“Given the Cold Shoulder: A Review of the Scientific Literature for Evidence of Reptile Sentience” by Helen Lambert, Gemma Carder, and Neil D’Cruze of the Department of Ecology, Evolution, and Organismal Biology, Iowa State University, shows a detailed analysis of available literature of these popular pets being kept by the millions worldwide.

To search for evidence of sentience in the scientific literature, Lambert and her colleagues compiled an extensive list of 168 of keywords that were used to refer to traits and various aspects of animal sentience.

Sentience is defined as the capacity to feel, perceive, or experience subjectively.

Lambert and her colleagues found 37 studies in which it was assumed that reptiles are capable of feeling “anxiety, stress, distress, excitement, fear, frustration, pain, and suffering.” 

Clearly, these discoveries show that reptiles are far more complex than many people realize. They also have practical implications for reptilian welfare making it more imperative to know about their emotional lives to provide them with the best care possible. 

Lambert and her colleagues conclude that reptiles are fully capable of experiencing a range of emotions and states and that we need to use what we know on their behalf. They write, “a better understanding of their emotional lives could help to inform a range of different operational initiatives aimed at reducing negative animal welfare impacts, including improved husbandry and consumer behavior change programs.”

Stress in captivity is likely to be chronic and is often due to poor husbandry or environmental conditions.

Transportation, treatment, and handling could also lead to acute stress episodes. Any treatment, extended stay or handling at the veterinary practice requires the provision of suitable accommodation, which is often not available.

A very interesting study of the Painted Turtle (Chrysemys picta), shows that nesting females do not have higher levels of some hormones if they are found near populated areas, whereas males did. 

Glucocorticoids are corticosterone (CORT) that measure stress levels invertebrate populations.

These hormones have been implicated in the regulation of feeding behavior, locomotor activity, body mass, lipid metabolism, and other crucial behaviors and physiological processes. 

Thus, understanding how glucocorticoids fluctuate seasonally and in response to specific stressors can yield insight into organismal health and the overall health of populations.

Behavioral change in reptiles, as in other animals, is often the primary indicator of disturbance, injury or disease. Just as a behavioral sign may be an indicator of stress or a physical problem, a physical sign may be an indicator of a behavioral problem, and abnormal behavior may result in injury and disease.

Significant differences exist between domesticated companions animal species such as dogs and cats and exotic non-domesticated pet species, which include all reptiles.

By contrast, reptiles possess few pre-adaptive features and are hard-wired with innate biological, behavioral and psychological needs that preset them to life in nature.

An inescapable factor that dramatically and negatively impacts on the biological suitability of reptiles to captivity.

Unlike dogs and cats, reptiles will almost universally be ‘life-restricted’ in small, arbitrarily and poorly conceived vivariums maintained by non-professionals. 

Contrary to common perceptions, reptiles manifest an array of abnormal behaviors that indicate stress.

While physiological stress measurements are available through blood and, less invasively, fecal sampling, numerous confounding factors are involved with this method, including a dearth of pure baseline data and the limitations of focused interpretation.

For example, human studies report that, while cortisol may be mediated by certain factors such as agitation-related stimuli, states including perceived stress, anxiety and depression may not increase cortisol. Extrapolation from these findings suggests that conditions such as under stimulation in animals may not be revealed through physiological measurement.

Reptile behavioral diversity approaches, parallels and sometimes surpasses that seen in birds and mammals. 

Normal behavior implies not only natural behaviors but also their appropriate range and context.

For example, in nature, it may be normal and healthy for an animal to spend hours of exploratory locomotor activity to hunt for food, whereas it may be abnormal and unhealthy for an animal to spend less than an hour pacing a small enclosure in a captive scenario with plentiful food.

There is a shortage of field-based behavioral observations for the vast range of species held in captivity and this deprives captive animal observers of good comparative information.

Relatedly, the inherent possible conundrum exists that some animals that may be stressed by field observations may change their habits. 

For example, eye contact alone between observers and free-living iguanas resulted in significant disruption of normal hierarchical perching.

Accordingly, stress-related states in captive animals in some cases could be underrated as ‘normal’ because they have been mistakenly based on human-invoked responses in the field.

Reptile keepers commonly interpret signs of ‘good feeding’, ‘good bodyweight’ and ‘active reproduction’ as positive indicators of welfare.

However, in isolation, these signs are poor indicators of welfare and may be misleading. 

Generally, captivity-related chronic stress behavior may result in increased abnormal behavior, behavioral inhibition, vigilance behavior, hiding, fearfulness frequency of startle, aggression, freezing behavior, and decreased exploratory behavior, reproductive behavior.

As with other assessments, many problematic behavioral issues may be ‘masked’ by acute arousal states modified by a reptile’s temporary presence and examination in the clinical environment.

Although normal reptile behavior in the acute clinical environment is unlikely,

The presence of normal signs does not imply an overall good health state where any abnormal sign is also observed.

Relatedly, some behavioral signs may be ambiguous, for example, sleep may be associated with normal or abnormal behavior or health.

A physical sign (such as an injury or topical infection) may be an indicator of an environment-related behavioral problem. 

The components of artificial environments are notoriously complex, involving issues that include, but are not limited to, space, temperature, humidity, light, airflow, and furnishings each with its array of known (and often more importantly unknown) key factors. 

Winning the National Lottery involves getting six correct variables out of 49 to beat a 1 in 14.5 million chance.

Putting that into perspective, in husbandry, the chances of six correct variables out of thousands of dynamic variables are very small and this may partly explain why many reptiles do not survive long in captivity.

Thermoregulatory issues

Reptiles naturally use behavior to select and occupy niche temperatures and attain precise thermal conditions. Inability to thermoregulate within precise, self-perceived (by the animal) needs and even concerning a single event may result in the exacerbation of acute stress as well as chronic debilitation.

Do You Remember When We Were Soaking Popeye Because We Thought He Was Not Thermoregulating?

Behavioral fever and stress

In reptiles, the fever response is primarily behavioral rather than physiological. ‘Behavioural fever’ is manifested by the compromised animal directly seeking higher than usual temperatures by selecting warmer zones.

Similarly, healthy but ‘stressed’ reptiles, such as those that react poorly to handling or intraspecies competition, may show ‘emotional fever’ and seek out higher temperatures until they ‘settle’.

It is probably important that they can seek raised temperatures after even minor stressor events. Handling may equate to capture and predation.

Voluntary hypothermia

In addition to voluntary hyperthermia, there is also voluntary hypothermia, a state where some injured or diseased animals appear deliberately to seek out lower optimum or very low temperatures. 

Climatic factors may stimulate hypothermia such as animals that seek to hibernate following the onset of a naturally cooler environment.

Where injured or diseased reptiles are concerned, it may be helpful to take into consideration that voluntary hypothermia may be a requirement for some animals to survive a problem. 

This is most likely because reduced microbial growth, physiological disturbance, and ‘quiescence’ and healing may in some cases result from a compromised animal’s ‘biological shutdown’. 

However, the strategy should be regarded cautiously in sick individuals and should not always be presumed or accepted as positive. Identifying this state is difficult, but maybe a useful differential for the clinician.

Appropriate thermal gradients are essential for health maintenance. The need to alter body temperature correctly may be determined by highly subtle physiological cues only perceptible by the individual animal, rather than by a human ‘guesstimate’. 

Although it is common practice to raise the body temperature of injured or sick reptiles artificially, in the authors’ view this intervention requires caution; while it may promote healing in some cases, rapid microbial overgrowth and toxaemic effects may be triggered potentially raising catastrophic physiological demands in an unprepared and compensated animal. 

Furthermore, a compromised individual may not physically be able to escape hyperthermia once it has reached preferred body temperature.

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