As husbandry for captive herpetofauna expands, we are seeing a positive drift in the direction of natural environments, and now ways to provide more than basic care. In this article we take a look at what it means to provide enrichment for animals, how it is provided in zoos, and how we can extrapolate these examples to create stimulating environments that benefit our reptiles’ and amphibians’ mental and physical health.

We’ve all likely seen animal enrichment methods in action, especially at zoos. While mammals (and birds to a degree) are considered sentient, feeling creatures that can experience high levels of stress and boredom in captivity, opinions differ on reptiles and amphibians. Alternatively, study on the matter is scarce.

While amphibians and reptiles may not be as social as a mammal or able to bond and ‘play fetch’ with us, there are indeed ways we can provide physical and mental stimulation within their captive environments which will benefit them in the long-term, as well as allowing us to further enjoy keeping them.

Reptile husbandry has made strides in recent years, beginning with better enclosure sizes, now branching out to the inclusion of beneficial UVB for all species and providing the absolute best care we can offer in a captive environment, taking note of natural behaviours and environments. This promises a better future for exotic pet welfare.

What do we mean by ‘enrichment’?

When we talk about animal enrichment, we mean the ways we can increase the quality of life for them in multiple areas that go above and beyond the ‘basic’ husbandry needed to keep them only healthy and alive. It should consist of physical and mental stimulation that is appropriate to the species in question, referencing their natural physiology and behaviour.

This is a common practice in zoos where animal welfare is kept to an exceptional standard. Animals are regularly exposed to dynamic environments, cognitive challenges and social opportunities with the same or different species. This is all to promote the animals’ ‘normal’ or natural behaviours through positive, stress-alleviating experiences.

A lemur relaxing in a hanging shelter.

Why provide it?

Providing enrichment promotes normal behaviours; compared to what is considered abnormal – pacing, attempts to escape, aggression, and other similar stress symptoms seen in captive animals. It would be reasonable to say true success of keeping a species in captivity is not only for it to appear physically healthy, but for it to display its normal behaviours as would be seen in in the wild – or as close as is possible.

The benefits are numerous. Mentally stimulated animals have more engagement in their captive environments and can feel more at ease, leading to better experiences for the observers and more positive relationships with caretakers. Physical activity enrichment provides exercise that keeps animals mobile.

Everyone loves seeing a happy big cat with a box.

Considerations

A substantial amount of preparation is required when planning and providing enrichment for animals. As mentioned, relation to the natural behaviours and activities of the species in question forms the foundation of how to incite these behaviours through opportunities provided by us.

Every wild animal has what is often called an ‘energy budget’. Much like we budget out our own time and energy, animals must do this day to day to prioritise how they will spend their energy most efficiently for survival, since energy is a costly resource when food is not a guarantee. Certain activities also carry an amount of risk (though this is not such a factor in captive settings). What they do, how they prioritise it and when they do it are all considerations to make when planning enrichment.

For example, a nocturnal animal is only going to be active during the night, so that is when enrichment should be scheduled for that animal. In all cases, enrichment should be introduced slowly and with supervision.

This kind of enrichment is a good method of prompting animals to exert their excess energy.

Examples of common enrichment strategies

• MANIPULATIVE/INFRASTRUCTURE – Hanging food items or toys to investigate from suspended ropes or providing otherwise ‘interesting’ opportunities that require effort and cognition. This technique can be used on many animal groups, and is a popular option with mammals. Structures to climb, such as rope bridges or wooden structures promote exploration and exercise. Appropriate species-mixing is also a beneficial form of enrichment in circumstances such as larger habitat recreations (e.g savannah herbivores).
• OLFACTORY/GUSTATORY – New smells and tastes are a source of stimulation. Changing textures of foods, such as freezing them or cramming them into a puzzle container will provide a challenging way to get food and treats. Tool use can be encouraged if the food can only be reached by using twigs, for example.
• EXPLORATORY – Similar to previous methods, involving supplying opportunities for investigation. Hiding treats in an enclosure, high and low areas/platforms, and different substrate additions work well. Especially good if the animals are fond of digging.

Examples of enrichment as seen in many zoos and used on a range of animals. Feeding methods, puzzles, exercise/physical enrichment, social groups and environmental experiences are all excellent ways to prevent captive stress and also create positive experiences for observing visitors while the animals exhibit responsive behaviours.

How can we apply this to herpetofauna (reptiles and amphibians)?

Opinions on the cognition and ‘emotional states’ of animals such as reptiles and amphibians do differ greatly compared to mammals, and as a result the benefits of enrichment or opportunities for exploration and play are poorly documented. There was even a point in history when reptiles and amphibians were not thought to experience fear and pain as mammals do – we of course know this is incorrect now.

However, it would be unreasonable to think they do not benefit from engaging environments that can mimic opportunities and situations they find as in the wild. There are also some documented examples of experiments in which amphibians and reptiles have been exposed to different enrichment types, which we will go into in due course.

Varanus prasinus and other monitor lizard species are thought to be some of the most intelligent reptiles, able to understand basic training and form positive relationships with keepers.

Abnormal behaviours for captive reptiles are mainly displayed as attempts to escape, or lethargy. ‘Glass climbing’ is a common sight in lizards and snakes making attempts to get out of glass fronted enclosures. This poses the possibility of friction injuries around the mouth. Inactivity and lethargy also point to inadequate interest in the environment and can cause issues resulting from lack of physical exercise or general disengagement with keepers and observers.

Even low-activity animals should display short periods of exploration and movement. Extremely ill-suited environments can cause elevated stress that can lead to  adverse health effects or increased aggression.

A less common documented symptom is self-destructive habits, similar to those seen in birds and mammals due to stress or boredom. A study by Burghardt et al. in 1996 using Nile soft-shelled turtles found that the introduction of ‘play’ items including balls, sticks and hurdles reduced self-mutilation occurrences greatly.

It would appear that reptiles such as the softshelled turtles can feel a degree of stress derived from boredom in captivity, which can be alleviated by opportunities for ‘play’ – similar to monitor lizards chasing and biting toys designed for dogs. Whether they find this ‘fun’ or are just exhibiting predatory or inquisitive responses, it seems supplying apparatus such as this for reptiles has a beneficial role to play.

Looking at enrichment benefits, it is noted that each family of reptiles function differently, and this often varies even further between species. However, all families have been found to benefit equally from something as simple as natural habitat design elements (Eagan 2018). So, even taking ‘advanced cognition’ or social opportunities out of the picture, simply replicating the natural environment for the animal to trigger natural physiological responses will be beneficial.

As a foundation of care, replicating to the best of our ability the natural microhabitat of the species in question is beneficial in providing a less stressful environment that is more stimulating and prompts natural behaviours.

This is also outlined in the Reptile Enrichment Workshop by Hawkins and Willemsen in 2004. They state that the physical characteristics of the captive environment can provide enrichment via: space, refugia, changes to spatial familiarity, temperature and light gradients (including seasonal variations), and water sources.

They go on to discuss contact with conspecifics (individuals of the same species). While keeping individuals together can be rocky territory, there is no denying that it is possible with the right resources and planning. Reptiles breed by contacting other individuals, after all. Some species are more colonial by nature than others.

A point made for cohabitation is to incite kin recognition in species that are to be released back into the wild through conservation projects.

Amphibians such as these Phyllobates terribilis, some others and some reptiles are often kept in small groups. It’s important to note that in most species, males cannot coexist peacefully, and of course males and females will breed which can be problematic. However, some female groups are possible with the right enclosure parameters and attentive care.

Other stimulation opportunities outlined include feeding methods and predator detection. Feeding should be made opportunistic rather than a rigid schedule if it is to mimic the instability of nature. Accurate prey selection promotes prey recognition. In a similar manner, predator recognition can be taught by introducing shed skin or droppings from a predator species into the enclosure for a fixed time, providing olfactory/chemosensory enrichment at the same time.

This was also tested on Podarcis liolepis (Catalan wall lizards) in a study by Londoño and colleagues in 2018. Scents from other individuals of the same species applied to filter paper were placed in the enclosure and as a result escape attempts decreased and were replaced with more ‘normal’ captive behaviours within the enclosure.

Scientific data aside, the online community of keeping herpetofauna is becoming a great resource when it comes to advancing health and welfare. It is certainly a viable route to find inspiration while the motivations for academic study on the matter may be scarce for the foreseeable future.

Podarcis liolepis.

Applying these theories to the hobby

We’ve looked at some fundamental ways we can make life more interesting for amphibians and reptiles. While we may not have the elaborate enclosures and resources as that of a zoo, we can take small inspirations to interact with our own animals and enjoy seeing them exhibit their natural activities and instincts while they feel more at ease living under our care. Here’s the concluding breakdown of methods we can apply.

• Accurate replication of the natural environment of your animal in accordance with its behaviours, e.g humidity, substrate, plant cover. This requires sound understanding of the species. ‘Bioactive’ environments are good but not mandatory.
• Appropriate temperature and light gradients. These give a choice for physiological regulation. Providing ample hiding opportunities is required.
• Varying temperatures and light exposure with the seasons. This can trigger responses such as brumation, reproduction, changes in appetite and activity
• Climbing/digging opportunity by using substrates and natural structures – provides enrichment and physical activity as well as more choice for heat/light exposure regulation. Bringing reptiles outside can also be an enrichment activity but requires a safe area and proper supervision in the right weather conditions.
• Changing the spatial arrangement of the enclosure for explorative enrichment.
• Vary food items and feeding methods/presentation. Add variety to the diet for overall nutritional health and make animals ‘work’ for their food. Try and avoid tong feeding and allow prey to be chased or actively searched for. Try scent trails and/or hiding prey. Remove any wasted.
• Direct interaction with conspecifics is not strictly necessary and can be simulated using shed skins or droppings for chemosensory investigation. Same applicable by predator species.

Once deemed very inactive and not at all arboreal, views on pythons such as the royal python are changing. These snakes can be surprisingly active, given the right opportunity, and it has been recorded that male individuals eat up to 70% avian prey and are often found in trees, suggesting a semi-arboreal lifestyle.

Don’t feel too lost on how to begin, looking at all these concepts. You can start off with something as simple as trying a new food with your animal, no matter their diet. For bearded dragons, for example, you have the range of plant and insect foods to try. Silk worms, horn worms and beetle grubs are less common food items, so why not give those a try as a treat? To go further, you could feed them in a way that requires some climbing or chasing, rather than handing them right over.

For snakes, the scent trail method of feeding is a very simple and effective way to get them to use their natural hunting abilities. Most snakes can also try other food items.

Remember to give fruits and other treats in moderation to avoid obesity or dental issues in bearded dragons and other herbivorous reptiles. Explore a varied diet, always researching that a food item is safe first!

And of course, don’t forget the natural enclosure design. This should now be the foundation we aim for when keeping reptiles and other exotic animals in captivity. Unless an animal is in treatment or quarantine, there is no need for plain setups with paper substrate. Something as simple as a deep loose substrate to allow digging and foraging can be very mentally and physically stimulating for amphibians and reptiles. Providing new places to climb and hide is also very beneficial – make the most of both the horizontal and vertical spaces!

How do I know if my animals are engaged and stimulated?

You will likely know by just observing them. Watch out for the abnormal behaviours – lethargy, constant escape attempts, or self-mutilation by accident or on purpose. If the animal acts as it should and displays signs of good health (good physical condition, appetite, activity, regulatory behaviour, positive or neutral attitude to caretaker) then you are likely on the right track.

Pushing the intention to do more than the bare minimum when it comes to husbandry and enclosure design will no doubt have a positive impact on the world of keeping amphibians and reptiles, reducing the cases of impulse purchases under the premise of a ‘cheap and zero maintenance’ pet resulting in inadequate welfare or neglect, which reflects badly on the community as a whole.

Be sure to discuss the matter with likeminded keepers in the hobby and share your experiences with enrichment. Going above and beyond the baseline care of reptiles and amphibians is a great endeavour to follow and on top of enhancing our animals’ lives and making the hobby more enjoyable for us, it improves public opinions on the hobby when they see how good captive welfare can – and should – strive to be.

Literature references

Burghardt, G. M., Ward, B. and Rosscoe, R. 1996. Problem of reptile play: Environmental enrichment and play behaviour in a captive Nile soft-shelled turtle, Trionyx triunguis. Zoo Biology. 15(3):223-238.

Eagan, T. (2018). Evaluation of Enrichment for Reptiles in Zoos. Journal of Applied Animal Welfare Science. 22(1):69-77.

Hawkins, M. and Willlemsen, M., 2004. Environmental enrichment for amphibians and reptiles. In ASZK Repfile Enrichment Workshop 2004.

Londoño, C., Bartolomé, A., Carazo, P. and Font, E. 2018. Chemosensory enrichment as a simple and effective way to improve the welfare of captive lizards. Ethology. 124(9):674-683.

www.wildwelfare.org