Comfortable Quarters for Amphibians
and Reptiles
in Research Institutions

Michael D. Kreger

Division of Scientific Authority
U.S. Fish and Wildlife Service
4401 North Fairfax Drive
Arlington, VA 22203, USA

 Rhinoceros iguana*
 


There are approximately 6000 species of reptiles and 4000 species of amphibians. Some are completely aquatic, some rarely leave the trees, and some are burrowers. They are found in almost every habitat on the planet. At first glance, it would appear difficult to list criteria for laboratory housing for such a diverse group of animals. However, there are three general keys to successful housing:

  1. a knowledge of the biology of the specific species including the basic, but essential needs of ectotherms;
  2. an ability to replicate the most important features of the reptile's or amphibian's natural environment in the housing and care provided to the animals in the laboratory; and
  3. caretakers who are able to recognize signs of discomfort, stress, and ill health in the particular species.

 
Figure 1*. Broad-spectrum fluorescent and black light tubes are placed over the screened top of this reptile enclosure. The heat lamp is provided on the side near the perches where the lizard basks. The plastic on the cage sides helps increase humidity.

   

Figure 2*. A young Komedo dragon on a tree stump. Many reptiles and amphibians use both vertical and horizontal space in their habitat. A small tank for tree-dwelling species with a complex, enriched vertical dimension that includes perches, foliage, etc. has more utilizable space than a larger tank with barren horizontal space.


       Many reptiles and amphibians use both vertical and horizontal space in their habitat. A small tank for tree-dwelling species with a complex, enriched vertical dimension that includes perches, foliage, etc. (Figure 2) has more utilizable space than a larger tank with barren horizontal space.

 

Figure 3*. Rhinoceros iguana basking. Note rocks and shelter at the back. Design factors such as a rock for rubbing during ecdysis (shedding), and retreats will give the animals some control over their environments.


       Furnishings can be simple, washable plastic such as PVC tubes. Materials that may leach chemical contaminants [e.g., dyes, fire retardants] must be avoided. Other design factors such as grooved "haul-out" sites for turtles, rough objects - such as a brick or a rock - for rubbing during ecdysis [shedding], basking/perching sites, and retreats (Figure 3) will give the animals some control over their environments by choosing locations according to their preferences (Figure 4). All cage props should be exchanged regularly or cleaned with a dilute bleach and water solution followed by rinsing with water and air drying until the residual chlorine has evaporated.

 
Figure 4*. Lizard basking on a branch. Note that water, multiple basking sites, and cover are provided.


      Shredded newspaper makes ideal burrowing material for some species of reptiles. Leaf litter and potting soil are suitable substrates but must be changed frequently. Sheets of newspaper make a highly recommended floor covering because they are clean, absorbent, inexpensive, and easy to change. Astroturf is more aesthetic; it can be easily sanitized and also provides a good rubbing material for shedding reptiles. To increase humidity, moss is a recommended substrate for small amphibians because it holds dampness well and provides cover. Moss and other organic material must be changed frequently to minimize bacterial and fungal growth. Other floorings like sand or wood shavings are not suitable for most species because they are often eaten by the animals and may cause digestive impaction. Toads, however, do well with a clean sand substrate deep enough in which to burrow (Gilman, 1994b). Most aquatic amphibians, like newts, frogs, and salamanders, do well with medium-size pebbles and gravel.

 
Figure 5*. The outside surface of three sides of these lizard breeding tanks is painted dark green so that the animals cannot threaten each other between tanks.


      Whether using a terrarium or an aquarium to house the animals, seams should be tight and, for reptiles, latches should be placed on all doors and lids. Because the animals will explore or attempt to escape, there should be no rough surfaces on cage walls or seams that can cause abrasions. Excitability and frustrated attempts to escape can also be reduced by eliminating the number of transparent sides on an enclosure. Frogs, for example, when placed into a new tank, tend to jump into glass walls as if the barriers were invisible. By covering the outside of transparent walls with opaque plastic or paint and providing appropriate retreats, the risk of physical trauma can be reduced (Figure 5).

 

Figure 6*. Snakes are secretive creatures. In captivity, they must be able to hide from perceived predators such as cagemates or the human attendant. A secluded place is critical for such a nervous and irritable species, who are reluctant to eat when they feel disturbed. Note the rocks and leaves enabling the snakes to hide.


       Most amphibians and reptiles are secretive creatures. In captivity, they must be able to hide from perceived predators such as cagemates or the human attendant. A secluded place is critical for nervous and irritable species, such as many snakes, who are reluctant to eat when they feel disturbed (Figure 6). Opaque plastic boxes with small entrance holes make good retreat sites and have the merit of being easily cleaned (Pough, 1991; Figure 7). Hide boxes provide psychological security through containment and familiarity of the immediate environment. They should be available in different zones of the temperature gradient - e.g., warm basking location and cool litter substrate - so that the animal(s) can always find a refuge in a thermocomfortable area of their enclosure. For some species, psychological security is provided by olfactory cues. Snakes and terrestrial salamanders, for example, will make less attempts to escape from their freshly cleaned home cages when a small amount of fecal material is left as a sign of familiarity (Chiszar et al., 1980; Jaeger 1986).

Figure 7*. Two hide-boxes, fresh drinking water, and newspaper flooring provide the basic furniture for small reptile enclosures. 


       Arboreal and semi-arboreal species should have access to perches on which they can bask and establish a territory, and onto which they can escape. Perch diameter, angle, and placement will depend on the individual animal's size and particular preferences. The availability of perches is a particularly important consideration in the group-housing context. Access to perches will allow the animals to retreat/withdraw to elevated locations, thereby avoiding unnecessary conflicts arising from horizontal space restriction.
    

The above recommendations are intended to meet the minimum conditions necessary to ensure survival and well-being of captive reptiles and amphibians in the laboratory setting. The great diversity of the species will make it necessary for each investigator or instructor to consult the professional and scientific literature (e.g., Bellairs, 1969; Elkan, 1970; Campbell and Busack, 1979; Cowan, 1980; Mattison, 1982; Duellman and Trueb, 1986; Mattison, 1988; Warwick, 1990b; Pough, 1991; Hilken et al., 1994; Warwick and Steedman, 1994; Berry et al., 1995) prior to acquisition of the animals intended for research or teaching purposes, to become well informed on their basic biology, their species-specific environmental and nutritional requirements, and their species-specific behavioral needs. Since there is relatively little published pragmatic information on the successful care of the great variety of amphibian and reptile species, investigators are well-advised to consult curators, zoo keepers and herpetoculturists who have first-hand experience in successful husbandry practices of the species they intend to investigate.

A Note on Salmonella

The Centers for Disease Control has determined that almost all, if not all, reptiles are carriers of Salmonella (Mermin et al., 1997). Incidence of salmonellosis related to contact with reptiles has increased in the United States paralleling the increase in households with reptile pets. Because Salmonella is only transferred to humans by ingestion, it is strongly recommended that anyone handling reptiles - or surfaces that reptiles may have touched - wash his or her hands immediately after contact. Washing facilities should be in or near the reptile housing facility. Whether or not amphibians are carriers of Salmonella is unknown, but the same preventive handwashing is encouraged after handling.


References

Bellairs A 1969. The Life of Reptiles (Volumes 1 & 2). Weidenfeld and Nicolson, London, UK

Berry DJ, Kreger MD, Lyons-Carter JL 1995. Information Resources for Reptiles, Amphibians, Fish, and Cephalopods used in Biomedical Research. National Agricultural Library, US Department of Agriculture, Beltsville, MD

Campbell HW, Busack SD 1979. Laboratory maintenance. In Turtles: Perspectives and Research Harless M, Morlock H (eds), 109-125. Wiley & Sons, New York, NY

Chiszar D, Wellborn S, Wand MA, Scudder KM, Smith HM 1980. Investigatory behavior in snakes, II: Cage cleaning and the induction of defecation in snakes. Animal Learning and Behavior 8, 505-510

Cowan DF 1980. Adaption, maladaption and disease. In Reproductive Biology and Diseases of Captive Reptiles. Society for the Study of Amphibians and Reptiles, Contributions to Herpetology No. 1 Murphy JB, Collins JT (eds), 191-196. Meseraull Printing, Lawrence, KS

Duellman WE, Trueb L 1986. Biology of Amphibians McGraw-Hill, New York, NY

Elkan E 1970. The management and the pathology of amphibians and reptiles. Veterinary Record 87, 197-199

Gilman J 1984a. Chapter III: Reptiles. In Guide to the Care and Use of Experimental Animals, Volume 2, 19-28. Canadian Council on Animal Care, Ottawa, Canada
Full Text: http://www.ccac.ca/guides/english/V2_84/chiii.htm

Gilman J 1984b. Chapter II: Amphibians. In Guide to the Care and Use of Experimental Animals, Volume 2, 11-17 Canadian Council on Animal Care, Ottawa, Canada
Full Text: http://www.ccac.ca/guides/english/V2_84/chii.htm

Hilken G, Willmann FIF 1994. Preferences of Xenopus laevis for different housing conditions. Scandinavian Journal of Laboratory Animal Science 21, 71-80

Jaeger RG 1986. Pheromonal markers as territorial advertisement by terrestrial salamanders. In Chemical Signals in Vertebrates Duvall D, Maller-Schwarze D, Silverstein RM (eds), 191-203. Plenum Press, New York, NY

Jones JP 1978. Photoperiod and reptile reproduction. Herpetological Review 9, 95-100

Mermin J, Hoar B, Angulo FJ 1997. Iguanas and Salmonella Marina infection in children; a reflection of the increasing incidence of reptile-associated salmonellosis in the United States. Pediatrics 99, 339-402

Mattison C 1982. The Care of Reptiles and Amphibians in Captivity Blanford Press, Poole, UK

Mattison C 1988. Keeping and Breeding Snakes Blanford Press, Poole, UK

Pough FH 1991. Recommendations for the care of amphibians and reptiles in academic institutions. Institute of Laboratory Animal Resources (ILAR) News 33(4), S3-S21
Full Text:
http://www4.nas.edu/cls/ijhome.nsf/44bf87db309563a0852566f2006d63bb/368199c3957ffc73852568dc005e26ee?OpenDocument

Pough FH 1992. Setting guidelines for the care of reptiles, amphibians and fishes. In The Care and Use of Amphibians, Reptiles, and Fish in Research Schaeffer DO, Klienow KM, Krulisch L (eds), 7-14. Scientists Center for Animal Welfare (SCAW), Bethesda, MD

Warwick C 1990a. Important ethological and other considerations of the study and maintenance of reptiles in captivity. Applied Animal Behaviour Science 27, 363-366

Warwick C 1990b. Reptilian ethology in captivity: Observations of some problems and an evaluation of their aetiology. Applied Animal Behaviour Science 26, 1-13

Warwick C, Steedman C 1994. Naturalistic versus clinical environments in husbandry and research. In The Health and Welfare of Captive Reptiles Warwick C, Frye FL, Murphy TB (eds), 113-130. Chapman & Hall, London, UK

Wright K 1994. Acclimation-Maladaptive Syndrome in captive amphibians. The Vivarium 6(3), 12-13


The views expressed here are those of the author and do not represent views of the U.S. Fish and Wildlife Service.

Michael Kreger is a biologist with the U.S. Fish and Wildlife Service (USFWS) Division of Scientific Authority. Prior to joining USFWS, he was a technical information specialist at the Animal Welfare Information Center of the U.S. Department of Agriculture where he specialized in non-mammalian research animals and zoo/aquarium issues. His Masters degree involved studying the physiology and behavior of phytons and skinks in response to handling. He is currently completing a Ph.D. focusing on behavior and survival of reintroduced whooping cranes.


*All photos have been taken by the author at the National Zoological Park's Reptile House in Washington, D.C.

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Figure 1* Broad-spectrum fluorescent and black light tubes are placed over the screened top of this reptile enclosure. The heat lamp is provided on the side near the perches where the lizard basks. The plastic on the cage sides helps increase humidity.

Figure 2* A young Komedo dragon on a tree stump. Many reptiles and amphibians use both vertical and horizontal space in their habitat. A small tank for tree-dwelling species with a complex, enriched vertical dimension that includes perches, foliage, etc. has more utilizable space than a larger tank with barren horizontal space.

Figure 3* Rhinoceros iguana basking. Note rocks and shelter at the back. Design factors such as a rock for rubbing during ecdysis (shedding), and retreats will give the animals some control over their environments.

Figure 4* Lizard basking on a branch. Note that water, multiple basking sites, and cover are provided.

Figure 5* The outside surface of three sides of these lizard breeding tanks is painted dark green so that the animals cannot threaten each other between tanks.

Figure 6* Snakes are secretive creatures. In captivity, they must be able to hide from perceived predators such as cagemates or the human attendant. A secluded place is critical for such a nervous and irritable species, who are reluctant to eat when they feel disturbed. Note the rocks and leaves enabling the snakes to hide.

Figure 7* Two hide-boxes, fresh drinking water, and newspaper flooring provide the basic furniture for small reptile enclosures.