Environmental Enrichment for Reptiles

For years, standard practice for reptile housing was to keep the animal in a minimalistic enclosure. The thought was that the reptile simply did not care about its housing (Figure 1). For the most part, reptile breeders had success with this setup with regard to reptile reproduction and fecundity (Figure 2). The standard line was that if a reptile was given a heat gradient, a light source, and a place to hide, then it would be happy (Figure 3). A similar minimalistic approach to cats or dogs would be quickly labeled as less than ideal.

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Figure 1

Common housing for water turtles. These turtle bowls were popular years ago but can still be found in pet stores today.

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Figure 1

Common housing for water turtles. These turtle bowls were popular years ago but can still be found in pet stores today.

Environmental & Social Enrichment Requirements

It is well established that all animals need to be able to perform biologically appropriate behaviors while in artificial environments.¹ Housing essentials should be determined by the caged animal’s natural biology. Although it may be unrealistic to review wild-matched husbandry conditions for all reptile species, it is not unrealistic to make the effort to provide proper housing and nutrition for the 3–4 dozen species that are regularly kept as pets.

Reptiles that would normally live for 2 or more decades under natural conditions often languish in captivity and succumb at an early age.¹ This is largely because the diet, ambient or environmental temperature, relative humidity, and lighting (appropriate wavelengths and photoperiods) provided to captive animals often do not parallel those that the animals have evolved to require. This dearth of environmental essentials is sufficient to induce stress and ultimately overwhelm the animal’s natural immunity to disease.¹ Stressed animals rapidly become immunocompromised, predisposing them to opportunistic infections, ulcers, and disease.

Related Article: Exotic Pet Ownership: Responsible or Not?

In relatively recent times, the need for these basic essentials has received more attention, and environmental enrichment is now a priority in captive environments.¹ Zoos, aquaria, and facilities housing captive animals are not only encouraged but, in many cases, required to provide for the psychological well-being of the species.

Environmental enrichment includes appropriate physical husbandry and psychological stimulation, and it provides the foundation for captive reptiles to display natural behaviors and experience minimal stress. This enrichment includes the necessity for natural terraria and mental stimulation.

An excellent way to provide the latter is to encourage natural behaviors. This can be accomplished by rewarding natural and shaped behaviors. Physical and mental enrichment has become standard practice for most professional zoologic facilities, and veterinary professionals should encourage home reptile keepers to use enrichment practices.

Allowing a captive animal the opportunity to make choices (ie, think) provides mental stimulation. Instead of languishing in one spot, waiting for something to happen, they should have the ability to make things happen. For example, providing separate areas within the cage where food items can be hidden encourages foraging behavior (eg, in partitions, inside hide boxes, underground, placed high in branches). The active effort to find food can provide physical and mental nourishment.

These behaviors cannot take place in simple box units such as the standard sweater box or shelf units that are commonly used in reptile keeping (Figures 2 and 3). Although these units are efficient with regard to cleaning, maintenance, and ease of access to the reptile, they are environmentally and psychologically sterile.

Types of Enrichment

The Association of Zoos and Aquariums (AZA) defines enrichment as: “A process for improving or enhancing animal environments and care within the context of the inhabitants’ behavioral biology and natural history. It is a dynamic process in which changes to structures and husbandry practices are made with the goal of increasing behavioral choices available to animals and drawing out their species-appropriate behaviors and abilities, thus enhancing animal welfare.”

Providing enrichment is not as difficult as one might think (see Three Fundamental Goals for Successful Enrichment). The basis for successful enrichment is a fundamental understanding of the species-specific natural biology. Research about where the animal lives, how it lives, what it eats, how it finds food, what its normal diurnal and annual rhythms are, its natural aging process, and its reproductive biology must be conducted. In addition, numerous companies now produce reptile care products that make providing these requirements relatively easy.²

Related Article: Reptile Housing

Species-Specific Enrichment

Knowledge of the species’ natural history can direct the design of a physical facility enrichment plan. Cage design will differ depending on whether the animal is fossorial (burrowing), terrestrial (land dwelling), arboreal (tree dwelling), aquatic (water dwelling), or a combination of these. A terrestrial snake that does not burrow does not need deep substrate, whereas a fossorial snake will be markedly stressed in an enclosure that has no soft bottom for digging. Providing sand, soft soil, a water source deep enough for swimming, and trees can all be added to captive environments to enhance these natural behaviors.

Some reptiles are diurnal (active in daylight) while others are nocturnal (active at night). Feeding during appropriate times will help with appetite and food acceptance. Again, some reptiles will eat off the ground while others will eat while climbing in a tree. Aquatic species may need to eat in the water (eg, fish eaters).

Food & Drink

While it is generally considered bad practice to feed live prey (eg, mice, rats) to the animal, the owner can encourage foraging by taking dead prey and scenting the cage by dragging the prey around the cage, along the walls, or over rocks. This provides a scent trail for the reptile to follow.³ In addition, many reptiles learn to drink from a water bowl, but others, such as the veiled chameleon, only drink from dew-dampened leaves. Setting up a misting system or a rainforest enclosure can provide the needed moisture to allow water to accumulate on the surface of the foliage, thus providing proper access for these unique species.

Social Enrichment

Some reptiles are receptive to humans and appear to seek out contact, but others are known to be more reclusive and require places within their enclosures to hide. Housing a delicate chameleon in a cage with minimal hiding space located in a busy room with loud noises and constant activity is a recipe for disaster. Knowing the species and providing appropriate housing and accessories helps ensure a low-stress environment and a healthy captive (Figure 4).

Figure 4. Realistic caging provides limbs for arboreal species, as well as branches and foliage to provide visual barriers. Natural or appropriate wavelength artificial lighting is mandatory for the well-being of captive reptiles.

Many reptile species are solitary, meaning they do not need companionship from conspecifics. Contrary to what the pet store clerk may tell the owner, the green iguana does not need a cage mate. In fact, pairing animals that are not gregarious can often be a source of lethal stress.⁴ Larger animals often crowd or threaten smaller conspecifics, preventing them from access to food and water. In addition, larger or more aggressive cage inhabitants may physically injure smaller or more timid animals.

Training as a Form of Enrichment

Figure 5. This alligator has been trained to present for examination by rewarding it with gelatin cubes. Photo courtesy of the Theater of the Sea.

For years, zoos have trained mammals to do specific behaviors—a dolphin may be trained to present its tail for a routine blood collection, or an elephant may learn how to hold up a foot for a nail trim. The assumption was that reptiles were not suited for this type of training, but this is incorrect, as many institutions have instigated target training for reptile species. 

For example, Komodo dragons are trained to enter a crate for weight measurement and blood draws, and crocodiles are crate trained to allow for similar behaviors and ease in transport. At one facility, the keepers have trained the alligators to present for physical examinations by using gelatin cubes as rewards (Figure 5).

This human–captive interaction is stimulating for the animal and provides constant enrichment.

DOUGLAS MADER, DVM, MS, DABVP (Canine & Feline), DABVP (Reptile & Amphibian), DECZM (Herpetology), is the co-owner of Marathon Veterinary Hospital, a referral practice in the Florida Keys. He is also the consulting veterinarian for the Marathon Sea Turtle Hospital, Monroe County Sheriff’s Zoo, Key West Aquarium, Key West Butterfly Conservatory, and Theater of the Sea. Dr. Mader is an internationally acclaimed expert in exotic animal medicine and travels over 50,000 miles every year teaching at veterinary conferences, veterinary schools, and specialty courses. Dr. Mader is also on the review/advisory boards for several scientific journals. He has published hundreds of articles in scientific and veterinary journals, national magazines, newspapers, and book chapters. He is the author/editor of Reptile Medicine and Surgery (Elsevier). Dr. Mader received his DVM from University of California, Davis.