Summary: An enriched environment for reptiles under captive management isn’t just a tank with some extra objects in it. To really enrich the lives of our reptiles, we need to be creative and introduce some novelty into their lives. This article introduces different ways that reptiles’ lives and environments can be enriched. From using food and feeding to provide cognitive enrichment, to making simple changes to the environment to give them new ways to move and new materials to experience, and even providing opportunities for social enrichment, Lori Torrini offers practical, creative, low-cost examples of how to provide for their needs.

Paper, cardboard boxes, tubes, tubs, baskets, rocks, branches, empty containers, scents, bedding, and dirt. Are those enrichment? They can be. Providing novelty to afford mental stimulation, and environmental complexity to promote physical and mental exercise and positive challenges, can be as simple as using items already found around the house, or repurposing items that would normally be thrown out as trash. Enrichment can always be more complicated, expensive, or naturalistic, or include bioactive enclosures with furnishings to rival a forest, but it does not have to be.

What exactly is enrichment?

First, let’s explore the difference between enrichment and an enriched environment. For the purposes of this paper, enrichment is an activity caretakers provide that adds novelty to the snake’s life stimulating the 5 enrichment categories discussed further on. Enrichment activities or items must be changed frequently to assure continued novelty, once something is no longer novel it is no longer enrichment.  An enriching environment is a permanent or semi-permanent state. Enriching environments are daily living conditions that provide options for snakes to choose among different behavioral opportunities enabling them to exercise their minds and bodies when they decide. An enriched environment provides activity options and environmental stimulation by creating an environmentally complex habitat for the snake to live in without making frequent changes to it. Opportunities to exercise choices within their environmentally complex living space versus experiencing novelty to increase stimulation are the difference between enriched environments and enrichment. This article’s focus is on enrichment.

The Association of Zoos and Aquariums (AZA) defines enrichment as “a dynamic process for enhancing animal environments within the context of the animal’s behavioral biology and natural history. Environmental changes are made with the goal of increasing the animal’s behavioral choices and drawing out their species-appropriate behaviors, thus enhancing animal welfare.”

What does that mean, and what’s the purpose?

The AZA care manual for the Eastern Indigo snake states, “Environmental enrichment, also called behavioral enrichment, refers to the practice of providing a variety of stimuli to the animal’s environment, or changing the environment itself to increase physical activity, stimulate cognition, and promote natural behaviors. Stimuli, including natural and artificial objects, scents, and sounds are presented in a safe way for the snakes to interact with.”¹

The Association of Animal Welfare Advancement uses the following definition of enrichment from the Association of Shelter Veterinarians as a guideline for best enrichment practices in animal shelters: “Enrichment refers to a process for improving the environment and behavioral care of confined animals within the context of their behavioral needs. The purpose of enrichment is to reduce stress and improve well-being by providing physical and mental stimulation, encouraging species-typical behaviors, and allowing animals more control over their environment.” Keep in mind when reading this definition that shelters in and of themselves are temporary living conditions for animals for a few days or weeks versus animals housed in permanent living situations for years or their entire lives.

The AZA categorizes enrichment into five components: cognitive, dietary, physical, sensory, and social. Animal shelters generally have four categories: cognitive, feeding, physical exercise, and novel experiences. Regardless of the organization, the premise is the same.

The goal of enrichment is to provide animals under captive management with mental and physical stimulation. This can be done by providing opportunities to express natural behaviors, but it can also mean giving them opportunities to experience new behaviors they wouldn’t necessarily perform in the wild.

Enrichment can be anything that provides reptiles with an outlet for the physical and mental energy they would normally use for survival and reproduction in the wild. It is to help keep them mentally and physically fit, and to avoid the development of stereotypies. Stereotypies are repetitive behaviors without apparent practical function and may be an animal’s attempt to adapt to its environment or cope with stress, or it may be an indication of nervous system dysfunction. Stereotypies commonly seen in snakes include nose rubbing, edging, glass surfing, pushing the nose against surfaces, excessive interaction with transparent boundaries, or excessive exploration of the habitat. In cases where these behaviors cease to be reinforcing for the animal or fail to result in meaningful outcomes, learned helplessness may occur, in which case the animal will show little to no activity, failing to express even simple species-typical behaviors, and may stop eating.

What enrichment can teach us about reptile species under captive management

Animals under captive management, including snakes and other reptiles, no longer have to use 100% of their energy budget on survival and reproduction, because they are usually being provided with what they need to live without having to work for it. They now have time to fill and energy to burn, and they will find other things to do with it. Of course, the amount of energy will vary by species, but we shouldn’t make assumptions about how much energy that might be. Observe the snakes during periods when they are naturally active and awake; if the species is nocturnal and no one is available to watch them, set up surveillance. This is the only way to truly know how active the animal is and discover if they are displaying any stereotypies.

For example, in one of the behavior research projects at Behavior Education with a species purported to be terrestrial and sedentary, quite the opposite was found to be the case when the animals were observed all night. They were initially housed in white quarantine tubs with paper for substrate, a water dish, and a hide. When observing the study animals during the day they rested in a hide or on the tub lip; however, at night they frantically moved around their tubs, striking at motion outside of the tubs, edging, pacing the walls incessantly, pushing their noses along the walls and lid, and displaying moderate to extreme stress. When moved into quarantine tubs with a clear side, a perch, a humidity hide, and multiple layers of paper towels, the stereotypies and stress behaviors ceased. They rested during the day as before; however, at night they moved around their enclosures in a relaxed and curious manner utilizing the simple items added. They spent time climbing and perching, draping on top of the humid hide or resting inside it, and curiously looking out the clear side with no striking. They also burrowed under the layers of paper towels in an exploratory fashion, not in a manner to indicate they were trying to hide. Without observing the animals at night, their stereotypies would not have been apparent. The addition of three simple items (a perch, a moss box, and layers of paper towels) and a clear side to see out of the bin immediately changed their behavior.

It is also worth pointing out that while providing opportunities for reptiles to express natural behaviors under human care is a key component in optimal welfare, they are in captivity.

They are not in a natural environment, so we shouldn’t limit ideas for environmental stimulation to only those activities an animal would do in the wild. A Western Hognose snake at Behavior Education occasionally uses perches to climb and to get into an ambush position when hungry. That is the keeper’s clue it’s time to feed her. A colleague has a Kenyan Sand Boa who spends a portion of each day climbing and who seeks time out in the open to explore the environment. There are anecdotal accounts from people of their Carpet Pythons burrowing, even though the species is semi-arboreal. These are a few examples of behaviors that may be observed outside the range of what would be natural for them to exhibit in the wild. If it is safe for the reptile, enrichment options outside the realm of presumed natural behaviors should not be ruled out.

A reptile that is both mentally and physically fit is going to have greater overall fitness, reproductive success, and longevity. Consider providing outlets for them to use their time and energy, whether it is a little or a lot, in healthy ways. Enrichment doesn’t have to be elaborate or complicated; be creative, because anything safe can work. Think about the general categories of enrichment mentioned above — cognitive, dietary (food), physical, sensory, and social  — and understand that they can and will overlap. Some will be more relevant to certain species of reptiles than others. Social enrichment, for example, will not be as relevant to snakes as physical enrichment may be.

Practical ideas for creative enrichment

The following are some options for consideration within each of the general categories. While you can be extremely industrious and create complex enrichment for your animals, the options mentioned here will be simple, easy, inexpensive ideas that anyone should be able to do with common items. Remember that enrichment should be stimulating or create good stress that will challenge an individual just enough to learn and grow without being distressful. When introducing enrichment items to reptiles, watch for any signs of moderate to severe stress (distress). It is the keeper’s responsibility to be familiar with body language in the species being observed that would indicate comfort and relaxation, being stretched outside of their comfort zone but still acceptable (moderate stress that diminishes quickly), or that is likely a natural response to a novel item. Keepers must also recognize when the snake or other reptile is approaching threshold or experiencing fear, anxiety, or distress. If the animal is distressed remove the item or other enrichment, and return the animal to a familiar environment where it feels safe.

Cognitive enrichment

Cognitive enrichment is anything that stimulates the reptile mentally. Contrary to what many people believe, snakes and other reptiles can problem solve, learn, and adapt their behavior accordingly. They have not survived millions of years of evolution by just being lucky. Reptiles are not outliers when it comes to brain anatomy. They have the same basic brain plan as other vertebrates. The general brain regions found in mammals, including the cerebral cortex, have homologies in reptiles.² These include the forebrain, midbrain, and hindbrain as well as a structure known as the dorsal ventricular ridge, which researchers believe is homologous to the mammalian neocortex.³ To this point the Orianne Center for Indigo Conservation (OCIC) makes cognitive enrichment a high priority, stating, “Behavioral enrichment and modes of learning for juvenile D. couperi will be essential in preparing snakes for reintroduction and may have important husbandry implications of all managed populations. The OCIC will create stimulating environments to increase exercise and promote both psychological and physical fitness. These techniques will also increase the fitness of snakes scheduled for release by helping them develop hunting skills and enhancing their problem-solving aptitude. This is a new field of research that will explore the relationship of cognition to adaptation.”⁴

For snakes in captivity, cognitive enrichment can be as simple as placing novel items into the snake’s enclosure for them to investigate or moving them to a novel environment to explore.

Mental stimulation can be provided by giving snakes puzzles to solve or mazes to figure out. Typically puzzles and mazes have food placed within them and the animals must find it or figure out how to get to it. Sometimes placing a scent within the puzzle or maze is also enticing, and the objects themselves with nothing inside can stimulate curiosity. Some of the best things to use for this are empty boxes, empty paper sacks, empty plastic containers, paper or plastic cups, tubes made of plastic or cardboard, crumpled up paper, or anything safe for the snake to climb through, in, around, or on. Empty boxes seem to be extremely popular with snakes, especially a whole bunch of boxes in a pile. Boxes that arrive with deliveries or empty boxes that were to be thrown away, like empty cereal boxes for example, are fine to use. So many things come in boxes; consider allowing captive reptiles to investigate them for a while before tossing them out.

For industrious keepers or those who may also dabble in animal training, consider teaching snakes and other reptiles to follow a target, go to a station, and respond to cues to perform specific behaviors.

https://youtube.com/shorts/2nO8ULsQQEU

The training itself is cognitive enrichment and the mental activity can be reinforcing for reptiles who voluntarily engage in it. This is done frequently with many lizards and crocodilians, but don’t underestimate the ability of other reptiles, including snakes, to learn to do natural behaviors on cue and to perform novel behaviors. In an amazing training study published in 2014, researchers were able to teach wild Burmese Pythons (Python bivitattus) to press a button, but only when it was illuminated, and open a door leading to food.⁵ Snakes at Behavior Education are routinely trained to target and station, and have learned to shift, station on a scale, hold still for exams and microchip implants, and recall to their handler.

Cognitive enrichment is limited only by keeper creativity. Anything that is safe and mentally engages the reptile will work. For example, finding food hidden inside boxes or empty plastic storage containers is a popular activity with many snakes, and the activity can be set up inside or outside of their enclosure.

Physical enrichment

Physical enrichment is simply encouraging the reptile to move. Physical exercise can often be stimulated by other enrichment categories like cognitive, dietary, sensory, and social. Encouraging snakes and other reptiles to climb, burrow, balance, move from one location to another, swim, grip, grasp, etc. can be accomplished by adding objects of various heights, sizes, shapes, and textures to the enclosure. Movement can also be encouraged by adding various temperature gradients that are far enough apart to stimulate travel between them. Adding scents to something inside the enclosure can stimulate curiosity, causing movement to the location of the scent. Encouraging reptiles to forage or hunt for their food is also a form a physical enrichment. This can be accomplished by hiding prey items, creating puzzle feeders, or placing food in mazes, all of which require the reptile to move around to get to their food.

For terrestrial and climbing reptiles, it is easy to place containers inside habitats that reptiles can climb through, on, in, or around. Cylinders, rocks, properly cleaned branches from outside, or even thick ropes encourage climbing, gripping, grasping, coiling, and balancing.

Laundry baskets are popular climbing areas for many snakes, if they can fit through the holes; one python at Behavior Education was observed for over an hour moving rectilinearly back and forth across a thick clothesline-type rope one evening.

For terrestrial or fossorial snakes who may burrow, providing substrate options is a great way to encourage movement from one location to another and allow physical burrowing. This can be accomplished by dividing the enclosure floor in half or into thirds and placing a different substrate type in each section. Substrates (e.g., aspen, paper, mulch, eco-earth, moss, bark, coconut husk, or others) can also be placed into shallow boxes or inside tubs, giving the snakes or other reptiles various locations they can move to and experience the difference. Some of these snakes may also utilize shallow pools of water, mud, or damp substrates.

For aquatic or semi-aquatic reptiles, or even for those who just like to swim from time to time, consider providing a swimming pool separate from their drinking water. This can be accomplished with large bowls, or filling tubs or bins with water. Plain water can be made more environmentally stimulating by placing a rock or rocks in the bottom or adding other items that are safe to get wet and that the reptiles can climb on or grip onto while in the water.

Remember, physical enrichment is likely going to be utilized during an individual’s normal active periods, which may not necessarily coincide with when keepers are watching them. If keepers are only with a nocturnal reptile during the day, there will not be much, if any, activity to observe. This does not mean they are sedentary. They are likely very active in the middle of the night while caretakers are sound asleep. Snakes or other reptiles may also be less active during an ecdysis cycle, and changes to activity levels will likely be noticed right before or after a meal, during winter versus summer, or during reproductive cycles.

Give snakes and other reptiles time to notice, discover, and investigate enrichment to determine if the enrichment item is something they will use or not. This may take several days or weeks. Just because they did not use it within the first day it was given to them does not mean they won’t ever use it. Some reptiles are immediately curious and investigate novel items, while others are cautious and may find new items reinforcing over time.

Consider a change of locations to promote physical enrichment. Allowing the reptile to come out of their normal living space for supervised time in a designated indoor or outdoor exercise space can encourage movement. This will also overlap with cognitive enrichment by providing mental stimulation in addition to the physical.

This will not be appropriate for all animals or keepers; however, for those who are able to provide it, freedom outside of the enclosure becomes very reinforcing for some reptiles, including many snakes. This should be voluntary and not forced. Remember, the point is to benefit the animal and not to cause it distress.

Sensory enrichment

Sensory enrichment has been covered somewhat in other sections, but here are some specifics. Visual, auditory, olfactory, gustatory, and tactile stimulation are all forms of sensory enrichment. The importance of each will be species-dependent, as some reptiles have poor vision and will not be as enriched by visual stimuli as those with keen vision. Research each reptile’s biology and natural history to find out which sensory modalities are relevant to them and focus on those. Make sure sensory and other enrichment items are not able to be swallowed by the reptile, and make sure they cannot injure their teeth or themselves on enrichment items if they get excited.  

Visual enrichment can include novel objects, varying colors, varying contrasts, movement, light, target training, station training, and objects the reptiles can see moving around or that they can cause to move, such as balls.

Auditory stimulation can be any sound the reptile reacts to with interest and curiosity. Avoid noises that induce stress or seem to cause agitation. Research each particular reptile’s auditory range for this category.

As with auditory, olfactory stimulation can be any scent the reptile responds to with interest and curiosity. For example, a Bredl’s python at Behavior Education spent several hours smelling a crumpled-up piece of paper that had a few drops of lavender oil on it. The same snake spent over a day engaged with a hide inside his enclosure that a “fruity” smell had been placed on.

Gustatory enrichment is anything the reptile can “taste.” For reptiles that have a developed sense of taste or for those whose sense of taste is strongly linked to their sense of smell, small amounts of novel food items or scents can be placed on objects for them to taste or lick. Make sure that whatever is used would be safe for the reptile if they were to ingest or absorb any of the gustatory enrichment. Many reptiles, including some snakes, will lick water droplets off glass or other smooth surfaces. Many snakes will spend time doing this when the insides of their enclosure walls are sprayed. Be creative and don’t be afraid to try things if they are safe for the animal.

Tactile enrichment is perhaps one of the easiest. If it is safe for the reptile, give them access to items of varied texture. Consider things like cardboard, plastic, ceramic, wood, logs, branches, leaves, any kind of safe substrates, cloth, stuffed animals, pillows, paper, rubber, etc. Tactile stimulation can include objects that are wet, moist, dry, squishy, hard, soft, rough, smooth, bumpy, cold, cool, warm, hot, or combinations of these. Remember that the objects must be appropriate for the species. Make sure the animal doesn’t try to eat something they shouldn’t or get burned by something.

Using food as enrichment

Food enrichment is anything that makes the eating experience take longer and become more involved than being fed in a bowl, on a plate, or with tongs. Encouraging the reptile to find their food through hunting or foraging enriches and prolongs the experience. This is easily done via mazes or puzzles, which can be created with empty boxes or other containers, hiding food inside the enclosure or a separate space, presenting food as a reinforcer during training sessions, freezing food in ice cubes (if appropriate for the species), placing food in water, creating movement of the food, or feeding live (if appropriate, safe, within personal ethics, allowed by the facility, and allowed by law).  

Use only those options that are safe for the reptile and appropriate for the species. The behaviors observed will likely vary based on species. For example, when colubrid snakes like bullsnakes (Pituophis sp.), who are active hunters and foragers, engage in foraging exercises, they will be quick to find the prey, consume it, move on, and continue foraging. When pythons participate in this same exercise, they move with slow deliberation following the scent trail, cautiously approach the food item, watch, and smell it for a while, and then consume it or do not consume it until it is wiggled first. Once they have eaten the food, pythons typically remain in ambush posture in that same spot for several hours prior to moving on, and when given the opportunity will return to that same spot repeatedly to take up an ambush position.

Anything that extends the process of obtaining a meal, encourages physical movement, requires problem solving, and utilizes the senses falls under food enrichment, even when it overlaps with the other categories.

Social enrichment

Social enrichment is just what it sounds like: interaction with others. Reptiles are typically thought to be non-social with a few exceptions; however, even those species that are generally solitary may benefit from the mental excitement of encountering a conspecific. This can be done by placing enclosures near each other where they can see and smell one another, by placing sheds from one animal in the enclosure of another, or by swapping an item from one animal’s enclosure into another’s. Obviously, these options will also be applicable to the sensory category of enrichment because they involve smell. For reptiles not known for combat or agonistic behaviors, or who are known to be social, it can be beneficially stimulating for them to be placed out in a large area together for supervised periods of time and later returned to their own habitats.

This brings us to the often-controversial subject of cohabitation. This may benefit some reptiles, under certain conditions, when housed appropriately but is a complex behavioral subject. It is very species-specific. Here is an example: The AZA Eastern Indigo Snake care manual advises against cohabitation and social interactions for this species due to agonistic behavior and cannibalism,¹ while the AZA Eastern Massasagua Rattlesnake care manual states this species may be “successfully housed in a variety of social configurations. Individual animals, mixed sex, and single sex groups can be housed for long periods without apparent problems. These snakes appear to be very tolerant of conspecifics. Rattlesnakes are often communal hibernators and there are no known reports of injurious interactions between animals.”⁶ Cohabitation is a complex form of social enrichment that may be appropriate for certain species. This must be thoroughly researched for individual species and is not for the beginner keeper.

Interaction with other species of animals, including humans, can also be a form of social enrichment that some reptiles may benefit from. Seeing, touching, and smelling other animals can be intriguing for reptiles. Use caution to make sure any such interactions are supervised and done in a safe manner for all involved. This will not be appropriate for all reptiles, and some get along better around certain species than others. Do appropriate research about inter-species interactions first before putting two animals in the vicinity of each other, and if unsure of how two species may react to one another, do not do it.

An example of successful interspecific interaction is that of a Bull Snake and Box Turtle who share a habitat in a mixed species exhibit at the AZA-accredited Pueblo Zoo. Although they have multiple resources and options such as multiple hides, they are often observed sharing the same hide together. Speculation as to “why” is not as important as recognizing that they are choosing to do that. If they did not find value in the behavior, if it were not in some way reinforcing to them, they would not do it, as they each have other options.

Conclusion

Enrichment for snakes and other reptiles should consider the natural history of the species, the personality and temperament of the individual animal, the reptile’s current environment, the skill and comfort level of the keeper when interacting with the animal, the overall health of the animal, the safety of the enrichment items, and the stress level of the animal. Enrichment experiences should be something of value that snakes and other reptiles find meaningful to them and should have a beneficial impact on their overall health and welfare.

For a complete playlist of videos on enrichment, go here: https://www.youtube.com/playlist?list=PLNbZzsRecQ2ac3qvbWHmR2jxsl0B0jUtx

References

1. AZA Snake TAG (2011). Eastern Indigo Snake (Drymarchon couperi) Care Manual. Association of Zoos and Aquariums, Silver Spring, MD. pp. 60.
2. Naumann, R.K. et al (2015) The reptilian brain. Current Biology 25:8, R317-21.
3. Schaeffer, D.O. & Waters, R.M. (1996) Neuroanatomy and neurological diseases of reptiles. Seminars in Avian and Exotic Pet Medicine 5:3, 165-171.
4. Central Florida Zoo, Eastern indigo snake conservation program. Last accessed: 4/26/2022
5. Emer, S.A. et al (2015) Predators in training: operant conditioning of novel behavior in wild Burmese pythons (Python molurus bivitattus). Animal Cognition 18, 269-278.
6. AZA Eastern Massasauga Rattlesnake SSP (2013). Eastern Massasauga Rattlesnake (Sistrurus catenatus catenatus) Care Manual. Association of Zoos and Aquariums, Silver Spring: MD.