Elise Gingrich Small mammals are becoming more frequently encountered in shelters than ever before. However, shelters may not be accustomed to dealing with some of these animals and their unique behaviors, which can differ significantly from those of the cats and dogs shelters historically serve. An in‐depth discussion of every small mammal species that could be encountered in the shelter setting is beyond the scope of this chapter; therefore, this chapter will focus on the most frequently encountered small mammals: rabbits, ferrets, guinea pigs, and a collective overview of common small rodents. Small mammals enter the shelter through a variety of pathways similar to most other species. As with these other animals, if they are surrendered or transferred from another sheltering organization, medical and/or behavioral information may be available; however, if the animal is stray there is no information other than the immediate history observed by the finder. Unfortunately, another common entry pathway for some small mammals is through confiscation (or, less often, surrender) of large numbers of a single species when hoarding or uncontrolled breeding cases are investigated. Just as with other animals that enter shelters, there should be standard protocols in place for small mammal handling and care. These protocols should encompass aspects of intake such as examination, parasite treatment, and vaccination as well as aspects of basic husbandry including enclosures, bedding options, nutrition, location within the shelter, and enrichment. Since there are a large variety of small mammals that could potentially enter the shelter, creation of protocols should be prioritized for the most frequently encountered species. Shelter intake data can be used to help determine which species are most common at a specific location. One other factor to consider with these species is whether there are local rules and regulations that limit or prohibit care of specific species; for example, ferrets and gerbils cannot be kept as pets in California (California Fish and Game Code 2019). The intake period—and associated processes—is perhaps the most critical period in the animal’s shelter stay. It provides an opportunity to initiate a physical and behavior care plan based on the animal’s condition. Every small mammal should be evaluated on intake just as any cat or dog would be; this includes an exam to assess for physical and behavioral abnormalities that require further evaluation by appropriate staff. It is important to understand the basic needs and behavior of the various species encountered so the shelter can ensure adequate welfare. Understanding normal behavior is of particular importance; without this understanding, staff may confuse normal species‐specific behavior with problematic behavior or, worse, may overlook abnormal behavior because they do not understand what they are observing. While specific housing requirements will vary by species, there are some generalizations to keep in mind when housing small mammals in a shelter setting. First and foremost, it is important to remember all housing decisions should be made to provide for an animal’s physiologic and psychosocial well‐being. The initial considerations should include the larger environment that is external to the animal’s individual enclosure. One important consideration at this level is where to place these animals within the shelter. While it is likely not possible to have different rooms for each species that may be encountered, care should be taken when deciding which species to house in the same room. Many small mammals are prey species and should never be housed in the same room as predator species such as cats. As predators, ferrets are a notable exception to this rule and they should not be housed in the same room as many of the other small mammals. The ambient temperature of the housing location also needs to be considered. While the specific temperature range will vary slightly for each species a general guideline to follow is that most small mammals are much more cold tolerant than heat tolerant. High temperatures can lead to heat stress and even death. It also important to make sure the housing areas are protected from excessive moisture and drafts. Laboratory animal temperature recommendations can provide guidance for creating appropriate housing protocols for the shelter. The Guide for Care and Use of Laboratory Animals recommends ambient temperature of 61–72° F for rabbits and 68–79° F for guinea pigs and other rodents commonly encountered in the shelter (Garber et al. 2011). The next housing consideration is the primary enclosure. A primary enclosure must be appropriate for the species, allow for normal movement and posturing, prevent escapes, allow for good ventilation (especially when ammonia levels are likely to be high), and be easy to clean. The enclosures should be as large and as enriched as possible for the shelter. In addition to protecting the animal’s mental well‐being while at the shelter, this will help to set an example for adopters and encourage appropriate housing after adoption. Some shelters may even choose to send the primary enclosures with the adopter to set them up for success. Even though several species of small mammals are social animals that do well when housed with other members of the same species, this does not mean animals from different sources should be housed together automatically. These animals must have the same criteria used for cats and dogs applied before co‐housing is attempted. The animals should be evaluated and determined to be at low risk for transmitting or contracting infectious diseases before housing them with other animals (of the same species). In addition to disease status concerns, the animals’ sterilization status should also be considered. Just as with cats and dogs, small mammals should not be co‐housed with the opposite sex once the animals reach breeding age. This is a very important consideration for small mammals, many of which are capable of breeding as young as eight weeks of age. The behavior of each animal should be considered also, to help make the housing choices as suitable as possible for every animal involved. Several general husbandry recommendations are applicable to all small mammals. When considering nutrition, it is imperative to feed a diet specific to the species of interest. Some species have very specific nutrient requirements, for example, guinea pigs cannot produce vitamin C so it must be added in their diet. It is best to avoid diets with brightly colored supplements, which are typically fruit and seed. Animals often preferentially eat these supplements, which typically have lower nutritional value. Since many of these small mammal species will enter the shelter infrequently it may not be feasible to keep food stocked for every species. Instead, the shelter should have basic feeding protocols available, so if one of these less frequent species does arrive at the shelter staff will know what type of food to obtain. Domestic rabbit behavior is very similar to that of its wild rabbit ancestor, the European rabbit (Oryctolagus cuniculus), with few exceptions. The primary difference is response to confinement; domestic rabbits have adapted well to confinement whereas wild rabbits are stressed by confinement and often fail to breed (Bays 2006). In the wild they live in large groups known as warrens and tend to be nocturnal. The population of the warrens can range from dozens of rabbits to more than 100; there tends to be an equal number of females and males (Parer 1977). The other significant difference is that domestic rabbits have become crepuscular and are most active in the morning and evening (Jilge 1991). Rabbits are prey species, which is an important factor to consider in their care because the highly developed flight response dictates a large portion of their behavior; for example, rabbits spend a significant amount of time sniffing as a way of surveying their environment even when frightened (Jenkins 2001). Due to their crepuscular activity, rabbits spend large portions of the afternoons resting. When rabbits are relaxed and resting, they stretch out on their sides or abdomens with hind legs stretched out behind them. Extremely relaxed rabbits may lay on their backs with their feet extended in the air. While they are resting, it is not unusual to witness thrashing and twitching movements; these movements are often mistaken as seizures by individuals unfamiliar with rabbit behavior. Rabbits will scratch and bite if nervous or not accustomed to being held; this is especially true when the rear limbs are not properly supported. When not properly restrained they will kick, which can easily lead to spinal fractures due to the high ratio of muscle to bone. The “football hold” describes a technique where the rabbit is kept close to the handler’s body with their whole body supported and their head directed toward the handler’s elbow (see Figure 23.1). This hold is ideal for nervous rabbits; it keeps the eyes covered, thus reducing struggling secondary to fear. The whiskers beneath the mouth are extremely sensitive, which is beneficial for grazing, but means rabbits do not like to have their noses touched. They also do not like to have hands placed below their noses or chins; when this happens rabbits often startle and can snort and scratch in response. This aggressive behavior is first seen at the onset of puberty, around four to eight months of age, depending on the breed of rabbit. At this age, intact male rabbits also begin urine spraying similar to intact male cats; they may mount other rabbits, objects, and even other pets. Intact, litter trained rabbits often start urinating and defecating outside the litterbox to mark territory. In order to prevent or decrease these behaviors, all rabbits should be surgically sterilized prior to adoption. This also tends to make the rabbits better pets and thus more likely to remain in the home. Sterilization also provides a health benefit for females as it eliminates the risk of the most common neoplasia in female rabbits, uterine adenocarcinoma; incidence varies by age but can be as high as 50–80% in certain breeds (Klaphake and Paul‐Murphy 2012). Figure 23.1 Example of a “football hold” for rabbits. The rabbit’s body is supported by the handler and its head directed toward the handler’s elbow. Rabbits are very territorial and use scent to mark territory. Rabbits will mark their territory with urine and feces; they also have three sets of scent glands on the body that secrete substances used in scent marking. One common form of scent marking is chin rubbing, which disperses secretions from the glands under the chin. Rabbits will rub their chins on inanimate objects to mark territory. Another scent marking behavior, which is frequently misinterpreted, is the deposition of fecal pellets. Fecal pellet deposits serve as a carrier for anal gland sections and can occur in an apparently random pattern throughout the rabbit’s territory or, in the case of intact males, along the periphery of their territory; fecal deposition can also occur in a common “latrine” site (Bell 1980) shared by multiple rabbits. The chin and inguinal scent glands are also used by female rabbits (“does”) to mark their young (“kits”). Does are aggressive to, and may even kill, kits that are not their own. For this reason, attempting to cross‐foster young rabbits can be very difficult. Rabbits are relatively quiet animals but will use specific noises to communicate a range of emotions, including fear, aggression, and contentment. It is important to be aware of the various sounds rabbits can make because several are similar but indicate very different affective states. For example, rabbits may make a low‐pitched purr by lightly chattering teeth when they are content. This noise is often accompanied by quivering whiskers. Teeth grinding, in contrast, produces a louder, crunching noise that is indicative of pain or discomfort, especially gastrointestinal pain. Sounds related to fear are typically high‐pitched screams, whereas those associated with aggression are often low grunting noises. Fear responses may also be denoted by a specific body language: the rabbit’s pupils are dilated, eyes are bulging, ears are flattened against the head, and the body is pressed flat against the ground with feet underneath it as the rabbit remains motionless. Rabbits also frequently thump their back feet in response to aversive stimuli to alert other rabbits. Rabbits are social animals and often do better in groups of two to three rather than individually housed. They exhibit behaviors such as grooming one another, lying together, and nuzzling (see Figure 23.2). While rabbits generally benefit from social groups, certain pairings can lead to significant aggression between the rabbits. Therefore, attempts to co‐house them must undergo careful consideration (see Section 23.3.2). Rabbits, especially juveniles, are extremely curious and can be chewers and diggers. These behaviors are common reasons for owner relinquishment. While the behavior is normal and cannot be stopped, it can be redirected to appropriate outlets. These include appropriate rabbit‐safe toys for chewing such as woven or wicker baskets, cardboard, or heavy plastic toys designed for large birds or dogs. These toys can be combined with food to encourage normal foraging behavior. For example, empty cardboard tubes can be stuffed with hay and a few pellets mixed in, or a small quantity of pellets can be put in a cardboard or tissue box that the rabbit can rip apart. These activities also serve as wonderful enrichment opportunities in the shelter environment. As with other species, it is important to rotate enrichment objects as interaction with objects decreases over time. Enrichment can help decrease boredom and destructive behaviors as well as encourage exercise; providing enrichment to maintain mental health is just as important as veterinary care is in maintaining physical health. Figure 23.2 Co‐housed rabbits lying next to each other, a behavior frequently displayed in bonded pairs. Rabbits have traditionally been kept in small cages or enclosures; however, giving rabbits access to more space, such as a small room or escape proof dog enclosure, promotes normal movement. Regardless of the type of enclosure, it is very important the housing allows for adequate ventilation. Rabbits produce large amounts of urine daily, so ventilation is necessary to prevent the build‐up of ammonia. When used, individual cages should consist of coated wire or steel bars instead of solid walls such as those found in glass aquariums or some cat cages. Ideally the entire floor of the enclosure should be solid; if a wire floored enclosure is used, then a significant portion needs to be covered with solid material, such as carboard or wood to allow time off the wire. This will help prevent the development of pododermatitis, a painful ulceration of the bottom of the feet that often results in infection and can be difficult to treat (see Figure 23.3). The enclosure should be large enough for the rabbit to hop three times and to stand up on its hind feet (Love 1994). Ideally rabbits should have space to demonstrate normal behavior. Exercise is important for both medical and behavioral well‐being of rabbits; those not given the opportunity to exercise are prone to obesity and pododermatitis. When rabbits have the ability to roam freely, such as in a large room, they will demonstrate typical rabbit “antics” such as running and kicking their hind feet up or jumping off the ground with twisting and sideways kicks in the air. When giving rabbits this opportunity, it is important to ensure the flooring is a non‐slip surface. Placing towels or thin foam mats can provide traction and prevent injuries in playful rabbits. Rabbits will also often stand on their hind legs with ears erect to check out the surroundings. It is important for rabbits to have space to perform these normal behaviors along with platforms to climb on. Accommodating these needs can be difficult in a traditional shelter environment, especially in older facilities that were typically designed to house cats and dogs. Many shelters have modified existing enclosures, such as those designed for puppies, to house rabbits (see Figure 23.4
23
Caring for Small Mammals
23.1 Introduction
23.2 Small Mammal Housing and Husbandry
23.3 Rabbits
23.3.1 Behavior
23.3.2 Housing
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