Understanding rabbit behavior and preventing and treating behavior problems

Most behaviors exhibited by pet rabbits can be linked back to their ancestors' lifestyles. Understanding how to manage these natural behaviors in a home environment as well as knowing how to prevent and treat problem behaviors will help rabbits and owners coexist peacefully.

Sharon L. Crowell-Davis, DVM, PhD, DACVB
DACVB Department of Anatomy and
Radiology
College of Veterinary Medicine University of Georgia Athens, GA 30602

February 2007 Veterinary Medicine

A pet rabbit's behaviors—and behavior problems—are consequences of the way its wild ancestors and their captive descendants lived and survived. This article outlines the natural behaviors of rabbits and shows how you can help rabbit owners prevent or manage common problem behaviors.
ORIGIN OF DOMESTIC RABBITS
Throughout the world there are more than 50 different species of wild rabbits and hares, members of the order Lagomorpha. The domestic or pet rabbit is descended from the European rabbit, Oryctolagus cuniculus, which originated on the Iberian Peninsula (now Spain and Portugal). The wild European rabbit is a highly social species that lives in complex social groups in warrens that sometimes become large.1"5
The Eastern cottontail (Sylvilagus floridanus) and other wild rabbits common in the United States are laeo-
morphs but are in different genera than the domesticated rabbit. Most do not build warrens.
SOCIAL ORGANIZATION
Within a colony, multiple subgroups of two to eight rabbits spend most of their time together.1-2-4 The females in the subgroup are typically related, while the males maintain a rigid dominance hierarchy by ritualized signaling. As young bucks mature, they are usually driven out of the subgroup by the older bucks and will seek to join another subgroup or even a different warren.6 The young bucks are most likely to integrate into a new sub-
group or colony outside of the breeding season. Members of the subgroup and colony all watch for predators when outside feeding (see "General Environment" ).
This living arrangement is often in sharp contrast to that of pet rabbits. Just as the highly social horse is often kept in the social isolation of stalls, the highly social rabbit is often kept in the social isolation of a hutch or cage. In general, rabbits are probably better off if kept in groups of two or more animals. However, as with all social species, appropriate social behavior is learned. A rabbit that is adopted as a kitten and subsequently kept alone will
have poor social skills and is likely to be either extremely aggressive or extremely timid when it encounters a member of its own species. Nevertheless, some rabbits can be habituated, desensitized, and counterconditioned to other rabbits. How long this process takes varies; some rabbits are calm and
adapt readily to new situations, while others are reactive and less tolerant of new situations.
Introducing unfamiliar rabbits Ideally, rabbits that are not littermates and are going to live together as pets should be introduced when they are still young, at about 6 to 12 weeks of age.7 Unfamiliar rabbits should be introduced gradually, especially if they are adults and one or both rabbits have spent a lot of time isolated from other rabbits. If possible, owners should begin by placing both rabbits' housing adjacent to each other so the rabbits can see, smell, and hear each other without being able to fight. If one or more rabbits are in a large enclosure or room, a new rabbit can also be placed—inside its own cage—within the enclosure or room (Figure 1).
Since rabbits are more likely to be aggressive when in their core area of activity, introductions outside of a cage should be done in a neutral area, rather than in or near either rabbit's regular housing. For direct introduction, harnessing each rabbit can be useful because it is easy to pull the rabbits apart if either one becomes aggressive. If either rabbit is unfamiliar with a harness, it should become so before the introduction, so that the
rabbit does not associate the harness with meeting a new rabbit. While a rabbit may freeze the first time it is harnessed, it will generally adapt faster than most cats do and will begin hopping around. Ideally, owners should take the harnessed rabbit to a lawn with clover and other plants it
can graze on, so it associates the harness with pleasant experiences.
Once both rabbits are comfortable with the harnesses, they can be harnessed, placed in a neutral area, and allowed to approach each other. Sniffing and lying next to each other are desirable behaviors that should be allowed and encouraged. Mounting should also be allowed as long as it does not trigger fighting. If a fight erupts, the rabbits must be immediately separated since they can seriously injure each other by biting and
by raking with their claws. If the rabbits are not harnessed, towels can be used to both bundle the rabbits and protect the person trying to separate the rabbits.
Similar to the introduction of unfamiliar individuals of other species, the time required for a successful and peaceful introduction of rabbits varies tremendously. Some rabbits will get along well within minutes, while others may require weeks or may not be able to be kept together at all.
GENERAL ENVIRONMENT
Lagomorph-specific behavior is substantially driven by the fact rabbits are prey animals. When considering pet rabbits, it is important to remember that their ancestors escaped predators by freezing, hiding, and, most important, escaping underground. As a result, a pet rabbit can often be seen standing on its hindlimbs, scanning the surrounding area—what lookout rabbits do in the wild. If anything alarms the rabbit, it will thump.
If a pet rabbit frequently thumps, this indicates that the environment is too stimulating or threatening. In such cases, the environment should be evaluated, and the cause of the rabbit's repeated alarm should be
ameliorated. Providing the rabbit with a place to hide, such as a wooden or cardboard box with an entry that is just large enough for the rabbit, can be helpful and will provide an opportunity for the rabbit to mimic normal resting behavior in the wild. Grooming is one behavior that indicates a rabbit is comfortable with its environment (Figure 2). Wild rabbits retreat to special galleries within the warren to rest, consume fecal pellets, and groom themselves.5'8-9
HOUSING
Appropriate housing is critical both to a rabbit's quality of life and to the development of the complex and interesting behaviors that make a rabbit a good family pet.
Origin of cage confinement Roman farmers kept rabbits in cages as meat animals at least 2,000 years ago.10 It was the keeping of rabbits as meat animals, rather than as pets, that is the origin of the custom of keeping them confined in small cages. After rabbits were domesticated as meat animals, the custom of keeping them spread throughout Europe. By the 6th century, monks were breeding rabbits for size and color. Rabbits were successfully introduced to Britain during the Norman Invasion, which began in 1066.
Later, during the industrial revolution, as people moved from farms to cities and were forced to leave large livestock behind, the keeping of small livestock, such as pigeons and rabbits, became common. A rabbit fancy emerged, with further breeding for various sizes, colors, textures, and coat lengths as well as for face length, ear size, and whether the ear was upright or lop. As part of the domestication process, rabbits would have been selected for tolerance of housing in small cages, as wild caught rabbits that were overly stressed by this unnatural condition would not have survived to reproduce in captivity.
2. Grooming is a sign that a rabbit is comfortable with its environment. In this case, the rabbit is outside on a leash and harness.
Environmental enrichment If kept in a small cage, a pet rabbit will survive as long as it is fed, given water, and kept adequately clean, but the rabbit is unable to engage in any of the complex behaviors that make it a good pet and that are important to its welfare. Keeping rabbits in larger housing or even loose in the house reveals an animal that is far more interesting. Rabbits play with toys or household items that they adopt as toys. They push toys around with their noses, bat them with forepaws, pick them up in their mouths and carry them around, and toss them. A rabbit that is well-socialized to people will seek them out to play or cuddle with. Rabbits can also be trained by using positive reinforcement techniques and can readily learn how to walk on a leash (Figure 3).1047
While rabbits will use large spaces in which to hop around and even make strong leaps into the air, a place to hide—as discussed above— should always be available since they have not lost the species-specific tendency to seek a cave-like area for security and rest.
FECAL PRODUCTION AND COPROPHAGY
A pet rabbit's digestive system is designed for a high-fiber diet. It produces two kinds of droppings. The most
common droppings are firm pellets about the size of small English peas. The second kind, caecotrophs, are generated in the cecum and are covered with mucus. Caecotrophs are produced and eaten when the rabbit is undisturbed, which is usually at night for pet rabbits and when underground for wild rabbits. The eating of caecotrophs should not be interfered with.
LITTER BOXES
A characteristic of rabbits that makes them successful house pets is the ease with which they can be litter-box-trained A rabbit trained to use the litter box will leave most or all of its fecal pellets in the litter box.
Placement and training Rabbits typically select one or more specific areas to be latrines and will almost always go there to eliminate. In the wild, this may be a scraped out area in the ground, called scrapes, which multiple rabbits may use.3"5 We can litter-box-train rabbits by taking advantage of their tendency to return to the same place to eliminate.
If a rabbit is kept in a large enclosure or cage, the owner should simply observe where the rabbit is eliminating and place a litter box there. Most rabbits will continue eliminating in the same place, even though the topography has changed by adding the litter box.
If a rabbit will be allowed to roam around the house, even part of the time, the owner should consider in advance where the litter box will be placed and begin allowing the rabbit its freedom only in that immediate vicinity. If the rabbit is already used to eliminating in a litter box in its enclosure, the rabbit may simply continue using the litter box in whatever location the owner chooses. If the rabbit is not already litter-box-trained, the owner should wait to see where the rabbit starts eliminating and place a litter box there. If the owner wants the litter box in a slightly different location than the one the rabbit initially picked, it may be possible to slowly move the box over several days without disrupting the rabbit's tendency to use the box. If the rabbit is going to be allowed access to a large area of the house, it will probably be necessary to offer multiple boxes spread throughout the house.
Design and use
Although conventional litter boxes made for cats can be used, the triangular litter boxes that fit in the corners of cages often provide sufficient room without taking up large amounts of floor space. Like cats, some rabbits will eliminate over the side of the box, in which case the solution is to get a box with higher sides.
In most other respects, rabbits are different from cats in their litter box usage. Some rabbits like to move their litter box around, either grabbing it with their teeth and tossing or pulling it or pushing it with their paws or head. If this is a problem, it may be necessary to clamp or tie the litter box in place. Some litter boxes are designed with hooks to keep them stable. Also, rabbits do not bury their excrement as cats do but instead leave their fecal pellets lying on top of the litter while the urine soaks to the bottom of the box. In addition, rabbits may spend a lot of time in their litter boxes, just lying or sitting in them—this is normal.
Litter
The predilection of rabbits to eat their litter makes litter choice important. It is best to avoid clumping litter, pine or cedar shavings, and clay litters with deodorant crystals since consumption of these litters will compromise a rabbit's health. Litter made from paper pulp and recycled paper products, aspen bark, compressed sawdust, straw, peat moss, oats, alfalfa, or hay are usually safe for rabbits.
Disruption to litter box usage

Changes in routine or the layout of the house or stressful events can disrupt reliable litter box usage. Stressful events include changes in the makeup of the family (the addition or loss of a human family member or another pet), illness, injury, and frightening events. If a rabbit's consistent litter box usage is disrupted, it may be necessary to briefly confine the rabbit to a small area of the house while routines are stabilized and the rabbit has a chance to adapt to whatever change has occurred. If the rabbit avoids its litter box entirely, it may have developed an aversion to that specific box. In that case, the owner may need to provide a new box with different litter.
COMMUNICATION AND SENSORY ABILITIES
Rabbits have a variety of vocal communications, which are important to understand. When content, rabbits purr, click, or grind their teeth at a low volume. Loud tooth grinding, grunting, or growling is a threat. Loud tooth grinding can also indicate pain. As indicated
above, a thump is an alarm call, while extreme fright is demonstrated by a loud scream, similar to that of a child.
Rabbits commonly leave olfactory communication signals by rubbing their chins on objects, leaving secretions from their chin glands. Urine spraying, in which urine is ejected backward in a spray, is most commonly exhibited by intact males toward subordinate males or toward estrous females being courted, wetting the other rabbit with urine. Males, especially intact males, that develop attachments to human caregivers may spray the caregivers.6'18 Neutering is the first line of treatment for this problem.
A relaxed rabbit will lie on its side or abdomen with its hindlimbs stretched out or will squat with its hindlimbs tucked underneath and its ears lain back. Rabbits exhibiting submission or fear will also crouch but will have their ears tightly against their heads while avoiding eye contact. Alert and attentive rabbits will have their ears up and mobile.
Like most animals that spend a large portion of their lives underground, rabbits have developed excellent senses of hearing and smell. The independently mobile, large pinna of the normal rabbit ear allows the rabbit to focus attention on sounds coming from particular directions. This ability is compromised in lop-eared breeds. The eyes are large and positioned on the side of the head, allowing for a field of vision of almost 360 degrees—an ability that is helpful for detecting predators.
MANAGING NATURAL BEHAVIORS
Some behaviors that owners may classify as problem behaviors are really normal behaviors that need to be managed in a way that is acceptable to both rabbit and owner.
Digging
Wild rabbits dig extensive warrens by scrabbling with their front claws and kicking soil away with their hindlimbs. Within the warren, most tunnels are narrow, allowing only one rabbit to pass at a time, although there are occasional wider sections that allow two or more rabbits to pass each other. Because digging is a natural behavior for rabbits, it is often exhibited by pet rabbits, which can be annoying to the owners of rabbits that choose to dig into quilts, seat cushions, or carpets.
This behavior is best managed by providing the rabbit with acceptable means of digging. If allowed outside, the rabbit can dig in the dirt. If a rabbit is kept in a large pen during good weather, a large volume of hay will allow the rabbit to dig and shape a mini-warren within the hay pile. Within the household, specific mats or pillows can be assigned to the rabbit. If the rabbit is allowed to dig without interruption into a certain object or in a certain area but is interrupted every time it tries to dig elsewhere, it will be likely to engage in this natural behavior where it is not interrupted.
Common behavior problems in pet rabbits
Failure to use the litter box Fear of people Aggression toward people Aggression toward other rabbits Destructiveness; digging and chewing
Chewing
Rabbits naturally chew a lot. Since pet rabbits may chew on harmful items— such as electrical cords—as well as valuable items—such as antique furniture— it is essential to rabbit-proof houses in which rabbits will roam freely. Once the potentially harmful items are removed or barricaded (e.g. put electrical cords in PVC pipe), it is important to provide the rabbit with numerous toys that it is allowed to chew on and play with. Non-toxic willow and apple wood sticks make good rabbit chew toys.
If a rabbit persists in attempting to chew on an item the owner wants it to leave alone, such as a chair leg, the owner should first try distracting the rabbit with a handclap and then redirecting its chewing to something acceptable. If the rabbit is persistent, mild punishment may be tried, such as tossing wadded up socks at the rabbit or squirting it with water. If any of the punishments frighten the rabbit, its use should be discontinued. The main disadvantage of using punishment techniques is the potential for causing fear responses. This must be carefully avoided. In some cases, rather than resorting to punishment, it may be best to revisit management, such as moving a valuable piece of furniture that the rabbit persists in chewing to an area of the house where the rabbit is not allowed.
CONSIDER MEDICAL PROBLEMS FIRST
Sudden changes in behavior may be indicative of medical problems rather than true behavior problems. For ex-
ample, rabbits that suddenly become aggressive or fearful or exhibit a decrease in playful interactions should be thoroughly evaluated for medical problems before behavior problems are considered.
However, behavior and medical problems can interact. All pet rabbits are unique individuals with preferences that need to be watched for and addressed. For example, some rabbits prefer to drink from a bowl while others prefer a drip bottle. Some rabbits prefer one kind of food over another. If these preferences are not recognized, medical problems may develop. Rabbits may become dehydrated if not offered water in the method they prefer or may develop gastrointestinal problems and lose weight if not offered the food they like, regardless of how nutritious the food is. Moreover, some rabbits have a preferred type of toy or play style. Such rabbits may get inadequate exercise, which can lead to obesity and muscu-loskeletal problems, if not offered the appropriate toys and space to play in.
As prey animals, rabbits often hide the fact that they are injured or sick, an aspect of their behavior that is critical to survival in the wild. As a consequence, casual observation of a seriously ill or injured rabbit (e.g. a rabbit with a broken limb or pneumonia) may be insufficient to identify that it needs medical attention. Rabbit owners should pay close attention to any changes in behavior, even subtle ones, since these can indicate the beginning of a serious problem. Owners should also physically check pet rabbits at least twice a day, running their hands over the body and looking at the area under the tail, for any changes from normal. Waiting to provide medical care until a rabbit's disease or debility is so advanced that it is obvious to even a casual observer may be too late, resulting in death.
HUMAN-DIRECTED AGGRESSION
While most people think rabbits are harmless, they can inflict painful injuries by clawing with their front claws—which are long and strong for digging—biting with their incisors, and kicking with their powerful hindlimbs. Most rabbits' human-directed aggression is motivated by fear or anxiety, with specific learning sometimes contributing.
Prevention
Preventing human-directed aggression is much easier than treating it. Rabbit kittens should be handled in a gentle and secure fashion, and this handling should continue as a rabbit matures, so it learns that having people pick it up, hold it, and carry it around will not result in harm or frightening incidents.
When children are in the household, it is essential that their handling of the rabbits be closely supervised. They also need to be educated about appropriate ways to pick up and hold rabbits. Hand-feeding rabbits special treats on a regular basis will help them learn that interactions with people can be a good thing. A rabbit raised this way will approach people and solicit attention and will not attack.
Treatment
If a rabbit is inadequately socialized when young or has an unpleasant experience with a person, it may subsequently try to bite or claw at hands reaching toward it. Initially, the biting or clawing is a simple attempt to defend itself from harm. But if the biting results in the hands going away and the rabbit being left alone, the rabbit will continue to attack all hands that approach it because of negative reinforcement (the behavior increases because it results in something unpleasant going away or staying away). For a rabbit with fear aggression, desensitization and counterconditioning coupled with strict avoidance of engaging in behaviors that frighten the rabbit will be necessary.
With desensitization, a rabbit is exposed to a stimulus that elicits a given response but at such a low level that the response is not elicited. Over time and successive repetitions, the intensity of the stimulus is gradually increased, ideally without eliciting the response. In this case, the stimulus is a person, and the response is fear.
With counterconditioning, a response is elicited that is both behav-iorally and physiologically (emotionally) incompatible with the undesired response. The details of implementing this treatment will vary, but in general, to begin, have the owner sit next to the rabbit's housing. When the rabbit is comfortable with this, the owner can open the door and stick his or her hand in the doorway without touching the rabbit. If the rabbit has developed the habit of charging hands and biting, it may be necessary for the owner to wear a leather or Kevlar glove so he or she is not injured. When the rabbit no longer charges, the owner can gradually move the hand closer and finally pet the rabbit gently and offer it treats. Once the rabbit is comfortable with that, it can be carefully lifted out and interacted with outside the cage. Alternatively, the rabbit can be allowed to leave the cage on its own and be interacted with once outside the cage.
Occasionally, rabbits will develop possessive aggression, in which they defend toys or other resources. Again desensitization and counterconditioning can effectively treat the aggression, although with an assertive rabbit it may be necessary to add gentle restraint when it charges people getting near its toys.
CONCLUSION
Rabbits can make excellent house pets. By understanding their wild ancestors' natural behavior and how these behavioral motivations affect the way pet rabbits interact with people and the domestic environment, we can prevent or successfully treat behavior problems in rabbits.
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