Adapted from M. Bush, L. Phillips and R.
Montali and other contributors
EDITORS' NOTE: Tigers are exhibited in a multitude of ways depending on the resources, climate and interests of the institution. There is no set criteria that defines how to exhibit tigers. However, the AZA Tiger SSP recognizes several institutions with good exhibits for tigers (listed alphabetically): Cincinnati Zoo, Indianapolis Zoo, Minnesota Zoo, National Zoo, NYZS/ International Wildlife Conservation Park, and the San Diego Zoo. All of these exhibits have several features in common: 1) relatively large outdoor space; 2) water pools, moats or running streams; 3) natural vegetation to avoid the grotto look; and 4) reduce or avoid bars between tigers and the viewing public.
A major component of tiger management is the facility designed and built to house them. From the outset, the team of people designing the structure include the architect, curators (animal, horticulture and education), veterinary staff, keepers, and director. Problems in design and construction lead to unfavorable facilities that may promote health problems and behavioral problems, such as inactivity and/or pacing, that can be prevented by forethought. Many physical aspects of the facility must be considered.
Irrespective of the enclosure use, the design must avoid a situation in which an animal cannot be fully seen for monitoring, or reached or shifted for potential treatment or immobilization.
Each enclosure must provide a cleanable, disinfectable water source accessible to both the tigers and keepers that can be shut off and drained. This allows monitoring water intake and water deprivation in certain clinical situations, such as pre- or post-immobilization. The non-reservoir watering systems (such as lab animal design self-waterers) can malfunction and inadvertently deprive the cat of water if not checked daily which may be difficult from outside the enclosure.
Lastly, a simplistic point, the facility must be secure to contain the tiger and protect the public and keepers. All doors, including the keeper access and shift doors, must provide the ability to be locked. The design must provide safe access to animal areas for keepers or the veterinary staff in the event a tiger escapes from its primary enclosure. The situation must be avoided where a tiger is out of its primary enclosure, cannot be seen, and can only be reached by directly entering the same space it occupies.
The size, nature and abilities of the tiger require secure containment. Modern exhibition of large cats is away form barred enclosures and toward large, naturalistic fenced and moated enclosures. Such exhibition requires careful planning (see Fig.
A tiger moat should be a minimum of 7 m wide at the top and a minimum of 5 m high on the visitors' side. This moat wall should be sheer and unclimbable. The moat wall on the tiger's side should be at a slight angle rather than vertical. There is no need for the moat to be very wide at the bottom, but it should have a large drain capable of carrying away rain, seepage, and wash water. There is no need for the moat to be very wide at the bottom, but it should have a large drain capable of carrying away rain, seepage, and wash water.
Fences should be at least 5 m high and vertical except for the top 1m which should be turned into the exhibit at about a 45 angle. This fence should be constructed of heavy-gauge steel with equally strong support posts and a concrete footing to prevent digging under the fence. Another way to prevent escape under the fence is to bury the fence at least 1m and angled toward the inside of the exhibit.
Care should be taken to be sure that there are no large trees close to the perimeter fence that if climbed by tigers would allow any access to the top of the fence. Adult tigers are unlikely to climb any vertical trees, but young tigers may climb.
Fence chargers and "hot wires" have no place in the containment of large cats. The only use of "hot wires" is to keep animals such as tigers away from some areas of the enclosure.
"Any perimeter fence around an exhibit for animals such as tigers should be checked every day before animals enter the exhibit to be sure that the fence has not been damaged" (J. Doherty).
In Germany minimum standards for a tiger enclosure are 25m2 for an adult pair and cubs for inside; 40m2 for outside. For each additional tiger an extra 4m2 inside and 10m2 outside are required.
[Editors' note: All government minimum requirements are generally perceived as too small].
Potential restraining include:
The newer exhibits in AZA zoos have moved toward the use of open air enclosures with vegetation and soil. Plants in the enclosure, which are recommended to provide shade, must be chosen carefully to avoid toxic species (see Exhibit Plantings). The dirt substrate becomes contaminated over time with micro-organisms and parasites thereby exposing the cats to potential concentrations of pathogens. Contaminated substrates should be periodically removed and replaced. To reiterate an earlier point, proper quarantine of animals helps reduce the potential contamination (parasitic) load. Pools and moats need to be designed for maintaining high water quality through filtration or draining and for ease of cleaning and sanitizing, as tigers tend to defecate in water. Drains should be of sufficient size to accommodate cleaning. Cold weather zoos must guard against moats freezing, which would permit possible escape of the tiger.
In enclosure areas that have non-dirt substrates, the choice in flooring is extensive. The most common material is concrete, which by itself is not the optimal surface due to its porosity, abrasiveness and hardness. Coatings over concrete, such as asphalt compounds, epoxy coatings, etc., provide a more acceptable surface by sealing, smoothing and softening the floor. The important concepts are that the surface can be easily cleaned, disinfected, rapidly dried, and non-porous to prevent accumulation of organic debris and contamination.
Disinfecting agents should be selected on the basis of effectiveness and low toxicity to tigers and should not be used in concentrations which exceed the manufacturer's recommended effective dilution. Phenolic compounds should be avoided due to the susceptibility of felids to this chemical. All detergents and disinfectants should be completed washed off following manufacturer's directions before the animal is returned to the enclosure. disinfectants should be completely washed off following manufacturer's directions before the animal is returned to the enclosure.
For effective cleaning, hot water and a detergent should be used to remove organic debris followed by or coupled with the disinfectant. All cleaning compounds, disinfectants and other chemicals along with their MSDS, OSHA sheets, or other warning labels should be reviewed and approved by the zoo veterinarian prior to use. These surfaces must provide good traction for tigers, especially when wet, but should not be abrasive so as to cause foot pad trauma during normal movement or exaggerated pacing. If the surface is too hard, trauma to bony prominences in normal resting or sleeping positions can result. Rubberized flooring, although soft, is easily damaged by tigers providing potential gastrointestinal foreign bodies. Walls or other raised surfaces should not be cleaned more than once or twice a week so as to maintain the animals' scent marks; enclosures that are cleaned too thoroughly and too frequently can make the animals unsettled.
The slope of the floor should promote drainage from the tiger's enclosure. The tiger's floor should be above drain level so that a clogged drain will not flood or spill into the enclosure. The design should provide easy shifting during normal daily management routines and especially during manipulative procedures for medical treatment, and to an area where the tiger can be routinely weighed. Good facilities provide the ability to shift tigers from one area of the unit to another without the need of crating or immobilization. Many designs fail in this concept. Under routine conditions the keepers can shift a tiger, but when it does not want to shift (e.g., aware of impending visit or presence of veterinary staff) it will not. Therefore, the facility should include provisions to force a reluctant animal to a desired location by use of narrow chutes subdivided by several doors.
The proper enclosure "furniture" provides the tiger with a variety of sites to stimulate activity, such as different heights, and can be constructed with materials providing a soft and warm place to rest or sleep off the floor. A raised wooden shelf in each enclosure allows the animal to be off the floor on a comfortable surface and gives adults relief from young cubs. A pool is considered to be very important even if it is in the form of a bath-like structure sitting on the floor as opposed to being built into the enclosure floor. Providing logs or timbers allow the natural behavior of scratching for claw wear and maintenance, i.e., to help reduce the ingrown claw and resultant problems.
Optimally, lighting should be a combination of natural and artificial illumination. Varying day-night light cycles are beneficial in reproductive cyclicity and health.
(adapted from D. Shepherdson)
Several suggestions have been made for ways to provide environmental enrichment and stimulation for tigers. Enrichment ideas include:
(adapted from E. Barclay and C. Lewis)
At the Metro Washington Park Zoo, large boulders physically keep the animals away from plantings and prevent soil compaction. Small decorative vegetation can be planted in the crevices between rocks, and grass can gain a strong foothold at the base of the rocks. Thorny or other unpleasant plants can also be used to protect more vulnerable vegetation. Hawthorne (Crataegus sp.), pampas grass (Cortaderia sellona), and barberry (Berberis sp.) have all been successfully used for this purpose. Controlling which areas are heavily used can help establish vegetation. "Seeding" certain areas with feces can persuade some cats to use those locations for defecation. Muddy spots can make other spaces less appealing for heavy use. Placing bones or other desirable objects at specific locations can encourage the use of that area. The placement of heat pads, shade and other sheltered areas can also help with planning landscaping strategies. Plants themselves can provide a wide variety of partial shelter and visual barriers.
An animal's enclosure is usually so static that any new addition causes considerable attention. If an effort is made to frequently move "furniture" and add new objects it will not be such a big deal when a few plants are added. Making unnecessary changes in a cat's environment regularly cannot only help increase the animal's activity level by providing a more stimulating environment, but also assists the cat's ability to adjust to necessary changes when they arise. Another approach is to wait until the weather is unattractive, such as during heavy rain or excessive heat. This keeps the cat in sheltered areas until the plants are not as novel.
All species proposed for planting in exhibits must first be approved by the veterinarian to make sure none are toxic. The species and quantities of vegetation chosen can have a great deal to do with the degree of success. Sometimes the method of "overkill" is utilized by planting excessive amounts of vegetation, gambling that some will survive the onslaught of trauma inflicted by exhibit residents. Certain cats seem to especially enjoy destroying certain species of plants. This can be employed to your advantage by using these species to distract the tigers from the plants you want to establish. If the cats pull up a plant, just kept sticking it back in, even if it is dead; eventually they get bored with it and in the meantime it has distracted them from the other plants. Dead trees and other dead vegetation can be left in the exhibits as natural looking furniture, barriers to protect other living plants, and to be used and abused by the residents.
Plants with aversion qualities such as thorny barberry, locust (Robina sp.), and hawthorne, cutting pampas grass and palms, or smelly, bad tasting cedar (Cedrus sp.) and juniper (Juniperus sp.) can be good choices for first exhibit plantings to get things started. Weeds can be a gardener's best friend. There are some plants that just cannot be killed. Mexican bamboo is great and gives a jungle effect; morning glory (Ipomoea sp.) and mint are others. Care needs to be taken not to let them get out of hand and strangle other plants, and so they need to be somewhat contained. There is also a problem with exhibits looking too similar if these plants are used too much.
Vegetation planted outside the enclosure and allowed to grow into it can have beneficial effects such as shade, visual barriers for the cats, and perceptually breaking up cement walls. There is a lot more flexibility in the selection of species used in these areas and the plants have a much better survival rate.
Care of the plantings is as important as getting them established in the first place. Exhibits at the Metro Washington Park Zoo are evaluated for pruning needs at least once a month by the keepers. Pruning stimulates growth and controls the growth pattern adding to plant survival potential. Leaving lower branches in place keeps cats away from the trunk or pruning at sharp angles can be a deterrent to the cats. Pruning also promotes visual avenues for the public to view the animals to the best advantage.
(from the Editors)
In order for an institution to participate in the AZA Tiger SSP, it must meet certain minimal requirements for tiger exhibit and off-exhibit holding areas. If it is to receive a breeding recommendation, the institution must have a minimum of three off-exhibit holding enclosures: one for the adult male, another for the female, and a third for the cubs. Cubs must be kept until three years of age. Some examples of good off-exhibit holding facilities are found at the Henry Doorly Zoo in Omaha, Indianapolis Zoo, and the Minnesota Zoo (AZA Tiger SSP opinion)].
Another example of a tiger holding facility was designed for the Indonesian Zoological Parks Association's program for the captive breeding of wild-caught Sumatran tigers (Fig.1).
Fig. 1. Schematic diagram of a tiger holding facility designed for the Indonesian Zoological Parks Association's (PKBSI) program for the captive breeding of wild-caught Sumatran tigers, constructed at Taman Safari Indonesia (Cisarua, Bogor) through support by the AZA Sumatran Tiger SSP. This facility was designed for breeding, not long-term holding, but could serve as a model for holding areas connected to larger outdoor exhibits. Facility design by R. Taylor, N. Reindl, J. Manansang and R. Tilson.
"Husbandry benefits for off-exhibit holding areas are that they allow close inspection of individual animals on a daily basis, monitoring of individual animals' food consumption, reliable shifting area once the animal is conditioned to move into and out of the area on a daily basis, and provide secure areas at night and during inclement weather (J. Mellen)."
Off-exhibit holding also provides for treatment areas out of the public view and seclusion for a stressed or ill tiger. Within this area, squeeze or restraint enclosures permit an alternative method of handling for procedures normally necessitating immobilization or anesthesia. A properly designed restraint enclosure allows simple close examination, collection of samples (e.g., blood, urine, or culture), or drug injection (e.g., antibiotics, vaccinations, anti-parasitic agents, or immobilizing drugs).
[Editors' note: The use of squeeze or restraint enclosures is controversial. Some contributors believe the use of such enclosures provides an alternate, less stressful method of drug injection. Others insist that the use of restraint cages is stressful and do not recommend their use. Thus, their use will have to decided on a case-by-case basis at each institution.]
The squeeze enclosure should be located where tigers regularly pass through so that they become familiar with it. It should be of a design that is quick to close on a rachet system; not the type that needs to be wound closed on a threaded bar.Maternity Den
For female tigers, a maternity unit provides an area where they feel secure to deliver and raise cubs. This area should provide a dry, warm, but also dark and small, secluded environment to promote good maternal care (see Chapters 5 and 6).
No matter how well designed your tiger facility is for containing tigers, either through accidents or acts of God, tigers sometimes get out of their enclosures. When this happens, it is important to respond immediately in a calm and professional manner in order to protect zoo staff and the visiting public, and to return the tiger safely to its home. To accomplish this, it is imperative that each zoo develop and practice its tiger escape policy. A sample tiger escape policy, which institutions can modify for their own use, is on page 81.References
Barclay, E.; Lewis, C. Strategies for exhibit plantings for large felids. ANIMAL Management and Conservation of Captive Tigers.