Indoor Enclosures

Physical Restraint Designs

Numerous institutions have constructed permanent physical devices to restrain their rhinos when necessary. Such “chutes” can be very valuable for physical exams as well as nutritional, reproductive or veterinary research. In addition to the following general information, please consult the Health chapter of this publication as well as Schaffer (1993) and Eyres et al. (1995). Institutions in the United States that currently have chutes and may be able to provide additional information include Henry Vilas, Saint Louis, Sedgwick County, Oklahoma City, Henry Doorly, Cincinnati, Caldwell, and Milwaukee County Zoos, Fossil Rim Wildlife Center, and the Wilds. Companies that may assist in chute design and construction include Animar Systems, Inc. (Springfield, MO, USA), Cummings and Son, Inc. (Garden City, KS, USA), and Mark McNamara of Fauna Resources (Tamer, Fauna Resources, Inc., Red Hook, NY, USA). In general, institutions modifying rhino exhibits or constructing new ones should incorporate a physical restraint area or device into their design.

Several physical restraint designs are effective for rhinos. These range from a small restricted area in which to contain the animal to an area that contains one or more hydraulics that will “squeeze” together to restrict an animal’s movement. In general, major restraint chute design considerations include strength, durability, type and function. It should be noted, however, that available space and animal size and disposition vary across institutions and should be individually addressed.

In general, both zoological managers and researchers emphasize that the general restraint area should be an active component of daily rhino management. Methods to accomplish this vary. A restraint chute or restraint area can be designed so that the rhinos must pass through it to exit the barn into their yard. If rhinos are fed indoors, part of the feed (e.g., produce, grain) can be offered in the chute area. Finally, more extensive conditioning (see Training chapter) can be particularly effective in habituating rhinos to physical restraint. Such a program should be attempted prior to detaining a rhino in a chute for an exam.

Rhino chutes should be manufactured out of steel or a combination of steel and steel-rein- forced wood. Some institutions have also used steel-strength aluminum (6061-T52 aluminum). Aluminum of this type is lighter and more maneuverable than steel, as well as potentially less stressful to rhinos because of “deader” sound properties than steel (i.e., when metal scrapes metal).

Permanent pass-through indoor restraint chutes (similar to those constructed for elephants) are especially effective for rhinos. With training, this type of chute may allow for detailed daily rhino observations. Further, inclement weather will not affect the use of an indoor restraint chute. The chute should allow restraint of the animal when it is passing through in either direction so that the shifting routine of the animal is not interrupted (Schaffer, 1993). The width of the chute should limit side-to-side movement while still allowing the animal to comfortably lie down. Animals can become wedged in tight-fitting chutes if the sides cannot be released. To alleviate excessive forward movement of the animal when it lowers its head, two vertical bars that push in from the sides of the chute to the shoulders of the rhino may be utilized. Quick release of these shoulder bars often relieves agitated animals without having to release them completely.

High-walled chutes or bars over the top of the chute keep the animal from climbing or rearing up. Horizontal bars in the chute’s entry gates and sides are hazardous for examiners when the animal lies down. Vertical bars on the sides can trap researchers’ arms if the animal can move forward. If the animal’s forward and side-to-side mobility can be limited, vertical bars or walls on all sides are recommended. The distance between these bars along the sides of the chute should be great enough to prevent the animal’s foot from becoming wedged if the animal rolls on its side in the chute. For personnel safety, this distance can be divided with removable vertical bars.

 

Rhinos may slam swinging doors; thus, sliding or guillotine gates are safer. A rectangular opening in these gates so that palpation can be performed should not pin the arm of an examiner when the animal is shifting. The distance between the vertical sides of this rectangular opening must be wide enough to provide for staff safety while still limiting the space through which a rhino could squeeze. Also, the horizontal bottom bar of this rectangle should be only a few inches from the ground, as animals frequently lie down. Solid doors on the outside of these gates can be used to stop rhinos, as they may attempt to charge even small openings. Additionally, good lighting and accessible electrical sources are useful.

A closed chute (Fig. 3.6) is another option that has been used successfully for the treatment of a rhino with a urinary-tract infection and another with infected lesions on its foot (Eyres et al., 1995). As noted in Figure 3.6, a typical closed chute has both front and back gates. The back gate restricts the rhino’s movement by sliding forward. Additionally, the hind end of the rhino is supported by a V-design that prevents it from lying down. This design also allows additional safety for the staff while working with the animal. In many respects, a closed chute does not depend as strongly on conditioning of the rhinos as does a squeeze chute, although acclimation is recommended prior to attempting any treatments within the chute. The design of a closed chute might necessitate an outdoor location in most cases; therefore, the use of this type of chute may be limited by weather. 

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A free-stall chute can be used for animals more sensitive to a confined enclosure (Fig. 3.7).

The design of this type of chute allows the rhino to enter or exit at its will and thus may help to keep rhinos calmer during procedures. Because there is free access, however, rhinos must be conditioned to target or stand still; thus, relatively non-invasive procedures also work best. Procedures that have been accomplished with a conditioned rhino in a free-stall include ultrasound and serial collection of blood and feces (Eyres et al., 1995).

A free-stall design can easily be incorporated into an existing pen or stall, indoors or outdoors. The open back of this type of chute allows the animal to enter and leave the structure at will. Protection of staff when working with the rhino is critical; a partial back wall constructed of vertical pipes allows staff to step out of the way (Fig. 3.7).