A vivarium (Latin, literally for "place of life;" plural: vivaria or vivariums) is an area, usually enclosed, for keeping and raising animals or plants for observation or research. Often, a portion of the ecosystem for a particular species is simulated on a smaller scale, with controls for environmental conditions.
A vivarium may be small enough to sit on a desk or table, such as a terrarium or an aquarium, or may be a very large structure, possibly outdoors. Large vivaria, particularly those holding organisms capable of flight, typically include some sort of a dual-door mechanism such as a sally port for entry and exit, so that the outer door can be closed to prevent escape before the inner door is opened.
There are various forms of vivarium, including:
Many kinds of plants are suitable for these habitats, including bromeliads, African Violets and Crassulaceae. Animals commonly held for observation include reptiles, amphibians, insects, spiders, and scorpions, small birds are also good.
The ground surface must be calculated to be enough for the species living inside, at their adult size. The height can also be important for the larger plants, climbing plants, or for tree climbing animal species. The width must be big enough to create the sensation of depth, both for the pleasure of the spectator and the good of the species inside.
Most used substrates are : common soil, small pebbles, sand, peat, chips of various trees, wood mulch, vegetable fibres (of coconut for example), or a combination of them. The choice of the substrate depends on the needs of the plants (type of ground), or of the animals (need to dig galleries for example), moisture (resistance to mold, conservation of water), the risks involved (e.g. the risk of absorption by an animal) and aesthetic aspects. Sterile vivariums sometimes used to ensure high levels of hygiene (especially during quarantine periods), generally have very straightforward, easily removable substrates such as paper tissue, wood chips and even newspaper.
Also, certain plants or diurnal animals need a source of UV to help synthesize Vitamin D and assimilate calcium. Such UV can be provided by specialized fluorescent tubes.
A day/night regulator might be needed to simulate with accuracy the alternation of light and dark periods. The duration of the simulated day and night depends on the conditions in the natural habitat of the species and the season desired.
Heating can be provided by several means, all of which are usually controlled by a thermostat:
Similar to lighting, a decrease in temperature might be needed for the simulated night periods, thus keeping living species healthy. Such variation need to be coherent to those found in the natural habitats of the species. Thermo-control systems are often used to regulate light cycles and heating, as well as humidity (coupled to built-in misting or rain systems). Light-dependent resistors or photo-diodes connected to the lighting are frequently used to simulate daytime, evening and nighttime light cycles, as well as timers to switch lighting and heating on and off when necessary.
The regulation of humidity can be done by several means:
Ventilation is not just important for circulating air, but also for preventing the growth of mold and development and spread of harmful bacteria. This is especially important in warm, humid vivariums. The traditional method consists of placing a suction fan (or ventilation slits) at a low level and another exhaust fan at a higher level, which allows the continual circulation of fresh air.