Amphibian Enclosures for Keeping Amphibians in Captivity

Enclosures for captive amphibians can range from spartan to highly complex systems. The initial cost of spartan enclosures is quite low and the setup time is minimal when compared to naturalistic enclosures. However, spartan enclosures lack the natural biological filtration of the complex systems, and thus require more manual cleaning and servicing. This intervention disrupts the amphibians’ daily life and, for some species, may be quite stressful.

Spartan enclosures are not aesthetically pleasing, and in some cases they may not accommodate the full range of behavior for a species. In order to achieve breeding success with many amphibians, and to simply keep many of the more delicate species alive, a more naturalistic enclosure may be needed.

Amphibians are ectotherms. They have little metabolic control of their body temperature and derive their temperature from the ambient environment— air, water, substrate, and, in some species, through basking in the sun. Like all other animals, amphibians prefer temperatures at which their body functions optimally for a given activity. Temperatures above and below the preferred temperature may be stressful and impair the animal’s ability to function normally. Thermal stress may lead to illness or even death.

Given a thermal gradient, amphibians are able to exercise some thermal control, often within rather broad limits, by behavioral and physiological adjustments. A thermal gradient allows an amphibian to develop a behavioral fever when combatting infection.

Amphibians have glandular skin through which they passively absorb and lose water, as well as respire (marginally so in caecilians); they do not drink water. Amphibians are subject to desiccation if put in a totally dry environment, and most species require frequent contact with a moist substrate and relatively humid air to maintain a positive water balance. However, some amphibians have difficulty with excessive water retention if put in an environment that is too wet. Given a moisture gradient, amphibians are able to osmoregulate by moving in and out of different moisture regimes, and by making postural adjustments.

Most amphibians have small body size, or at least “stand short.” Their microhabitat is the interface of the leaf litter, the surface of a leaf, the top layer of the soil or stream bottom, or the subsurface environment of rocks and burrows. Care must be taken to look beyond the larger, macroenvironment where temperature, humidity, and light levels may be strikingly different than they are in the world occupied by these small animals.

Most amphibians are secretive. In their natural habitat, they are often preyed upon by other animals. Cryptic behavior, often augmented by camouflage, is an integral part of their life. Even bold species with bright aposematic (warning) coloration usually flee or hide if sufficiently threatened.

The olfactory sense is well developed in most amphibians, especially in burrowing toads, newts, salamanders, and in caecilians (see Duellman & Trueb, 1986 for a review). Pheromones are important elements in the behavior of many species. The spatial pattern of pheromonal signals can strongly define an amphibian’s world.

When selecting housing for an amphibian, it is important to consider not only the lifestyle of the desired species, but how the enclosure will be maintained over the long term. Ideally, an enclosure and its life support system should require little servicing, and can be tended with a minimum of disturbance to the cage inhabitants. A stable environment, with minimal interference by human hands, can be critical to success with delicate species of amphibians.

It is wise to plan ahead and have an emergency setup available, should a sick or injured amphibian suddenly need to be separated from the group. When possible, compromised animals should be treated in their home enclosure. This is the familiar environment in which they will feel the least stressed, and presumably, their immune systems will function at their best. If the problem is social in origin, it may be necessary to temporarily or permanently remove cagemates. In any event, it may be less stressful for the sick or injured animal to be isolated in its normal vivarium and allowed to recover without interference or possible stress from cagemates.

If there is an adequate second enclosure, it may be best to remove the healthy animals from the home cage, since they are in better condition to cope with the stress of a move than their sick or injured cagemate. However, residual pheromone contamination from the former cagemates may continue to be a source of stress to an ill amphibian left in its original housing. If pheromone contamination or any other chemical contamination is suspected, the ill amphibian should be moved into a previously unoccupied vivarium.