Chapter 39 Behavior of Small Mammals
In many cases, the behavior of small mammals in captivity is very similar to that seen in the wild. Therefore, because of the constraints of confinement and unrealistic expectations of owners, behavioral problems often arise from the owners’ inability to provide for normal behaviors. Most small mammals that are kept domestically are also prey species, which causes them to be more susceptible to stressors associated with actual or perceived predators. Overall, if their psychosocial needs are not addressed and their instinctual personalities cannot be expressed, the result may be additional behavior problems and even failure to thrive.
It is imperative that veterinary practitioners understand what is normal for each species, so that behavioral cues associated with fear or stress as well as abnormal behavior are noted and addressed as soon as possible. Veterinary staff must be educated on what signs to look for in the daily care of these pets and what questions to ask during anamnesis. Equally important is to educate clients about these subtleties so that anxiety, discomfort, pain, and disease are detected and alleviated more promptly.
The behavior of small mammals is a very large topic covering many species. For this chapter, therefore, only those behaviors that are not associated with the medical care of rabbits, ferrets, and some other more common species are covered. Many of the behaviors associated with the medical care of these animals are covered in other chapters. For a more complete reference on the behavior of small mammals, the reader may refer to Exotic Pet Behavior—Birds, Reptiles, and Small Mammals.3,4,11,21–23
Rabbits are a very social species and, in the wild, live in large stable groups or warrens of up to several hundred animals.29 Because of their highly social nature, rabbits do best if they are kept in groups of two or three or more and given the right combination of companions and the proper introductory time (see “Introduction of New Conspecifics,” below). By ensuring these conditions, inseparable bonds can be created. In the laboratory setting, domesticated rabbits grouped in small social groups were found to have increased social contact and exercise34 and less stereotypic behaviors, including pawing at the corners of the cage, overgrooming, wire biting, overeating, and playing with the water supply.4 In the hospital setting, allowing bonded mates to stay together may help to decrease stress and increase the success of treatment.5,20 Rabbits can also form strong social bonds with human companions and with other domesticated pets. When not socialized with different animals and people and handled extensively at an early age, rabbits tend to be more shy and fearful and have more trouble adapting to new situations for the rest of their lives. As with other pets, it is important that introductions be performed in a careful and safe manner. Additionally, all interactions with other pets should be supervised by an adult, because domestication does not abolish the natural instincts and behaviors of predator species such as dogs and cats.
Rabbits communicate with each other and with human companions with marking behaviors (see “Territorial and Destructive Behaviors,” below) and with verbal and postural forms of communication. Verbal and postural communication behaviors with which the rabbit caregiver should be familiar are listed in Table 39-1.
|Name of Behavior||Description of Behavior||Function of Behavior|
|Fear posture||Will lie motionless in a crouched position with feet beneath body, head extended, ears flattened against head and eyes bulging||Make the rabbit appear smaller in order to be less likely to be noticed by a predator|
|Alert posture||Ears are held forward or laterally||Allow the rabbit to hear better and to be able to bolt if needed|
|Erect tail||Tail is held in an upright position away from the body||To exhibit excitement or anticipation of a happy event or if threatened|
|Licking a companion||Lick a bonded mate, a human companion, or other trusted pet||A sign of affection|
|Nipping||Biting gently||To solicit attention|
|Biting more assertively||Signals anger|
|Weaving/circling||Weaving in between feet or circling the feet of the human companion||To solicit attention or a courting behavior|
|Scanning||Moving the head horizontally from side to side especially when being carried||Evidence of impaired vision or difficulty focusing|
|Tail twitching||The tail is twitched rapidly back and forth||When urine spraying or to exhibit sexual interest|
|Presenting||Lying flat on floor with feet tucked, head extended, and chin on the floor||To solicit petting by human companions or for grooming by another trusted rabbit|
|Begging||Sitting vertically with front legs elevated off the ground||To solicit food, treats, or attention|
|Nudging gently||A push using the nose on a human or another rabbit||To gain attention or to signal “enough attention”|
|Aggressive nudging/digging||Using the nose to push and front feet to dig at objects||Signals anger or irritation|
|Tooth purring||A low-pitched hum with teeth lightly vibrating and whiskers quivering||A sign of contentment|
|Teeth grinding||A slower, louder tooth crunching with eyes bulging||A sign of pain|
|Chinning||Rubbing underside of chin on objects or bonded mates or humans||To mark territory or possession of objects or companions with secretions from scent glands on chin|
|Urine spraying||To spray urine on objects, people, or other pets||To mark territory, also a sexual behavior|
|Head shaking, ear shaking, and/or body shudder||To vigorously shake the head, the ears, or the whole body||Signals unwanted handling or when settling down|
|Aggressive posture||An upright stance with ears flat and tail stretched out, also may kick high and backward||To signal anger|
|Thumping or foot stomping||A single or repetitive stomp with the hind foot or feet||Signals anger or an alarm or warning of danger to other rabbits|
|Vocalization||Description of Sound||Function of Vocalization|
|Grunt, growl||A growling or snorting sound sometimes like a bark||Signals anger, annoyance, or territorial protection|
|Honking/oinking||A honking sound||To solicit food, attention, or courtship|
|Scream||A high-pitched repetitive scream||Signals fear, terror, or pain; may make this sound when seizuring or when dying|
|Wheezing/sniffing||An intermittent nasal sound that is often mistaken for a respiratory infection||More vocal rabbits will make this sound to show irritation|
Normally, rabbits are intelligent, inquisitive, and inventive; research has shown that rabbits kept continuously caged exhibit more nervous behaviors than rabbits kept in an open area.12 These attributes are often difficult to appreciate when a rabbit is caged most of the time; therefore it is important for rabbits to be given time out of the cage in a safe area for at least several hours a day.
Rabbits will nudge with their noses or beg on hind legs for attention from human companions as well as from bonded rabbit mates and other pets they have learned to trust. Both male and female rabbits will also weave in and out of their owner’s feet to gain attention and if “courting” them. They will push and toss objects around5 and jump on and off the couch.
If a paper is wadded and thrown, a rabbit may chase after it and sometimes will retrieve it. Rabbits like to instigate chase games with other rabbits and with humans, but a human companion who chases a rabbit may be more likely to be perceived as a predator than a playmate. Juvenile rabbits are particularly playful and need lots of space to run, jump, and twist. An extremely happy or excited rabbit may perform what has been fondly called a “binkie”—a jump high in the air with a twist similar to what an excited lamb will do.
When rabbits are through with play or being handled, they may nudge with their noses to say “enough attention.” An irritated shake of the head or vigorous ear shaking may also signal displeasure at unwanted handling or the need for time to settle down. A rabbit will also shake its body (much as a dog might shake off water) as it settles down, and as if to shake off unwanted attention. When not playing or eating, rabbits spend a lot of time resting sternally or sleeping on their sides.
Undesirable behavior in rabbits includes fecal and urine marking, chewing, digging, and aggression—either rabbit to rabbit or rabbit to human aggression. All of these negative behaviors are most obvious at about 3½ to 6 months of age, when rabbits become sexually mature.
Boundaries will be tested as rabbits exhibit more instinctual behaviors, become more assertive and mischievous, and develop a stronger drive to exhibit more territorial behaviors as well as to perform other behaviors that humans may find undesirable. It is also at this time that they are establishing a social order within their group of humans, other rabbits, and in some cases other pets. This strong will for autonomy and independence may be viewed as a nuisance by unprepared owners as the rabbits become less cute and cuddly almost overnight.
Clients must understand that these are normal instinctive behaviors and not meant to be “spiteful.” These negative behaviors are a temporary function of adolescence. With careful handling, time, and having the rabbit surgically altered, these behaviors will usually lessen. New owners often have unrealistic expectations for their rabbit pets and must realize how important it is to understand that, as individuals, they may not all react in the same way to similar situations. It is important to understand that each rabbit has a unique personality.
It is also important to realize that how the caregiver responds will determine his or her future relationship with the pet rabbit. The rabbit caregiver must reward desirable behaviors instead of accidentally rewarding undesirable ones. Alternatively, he or she can control the environment so that the undesirable behaviors do not occur or occur less.
Aggression that rabbits exhibit towards humans is primarily motivated by fear.9 As with other domestic pets, negative behaviors can be inadvertently reinforced as caregivers pull away from the pet and interact with it less in response to an adverse interaction. For instance, if a rabbit bites a human and that human stops handling the animal, it may learn that biting will keep humans away. Also, any rough handling in response to mischievous behavior can cause damage to the trust relationship that a rabbit has with its caregiver, thereby creating and/or reinforcing an adversarial relationship. Behavior modification (see “Behavioral Training Techniques for Small Mammals,” below) is recommended for rabbits that have developed fear aggression.9
Aggression between rabbits is usually due to defense of territory, fear, and/or the desire to establish dominance (fighting, for instance, to establish rank or priority access to resources such as food or potential mates), all of which can become worse as these animals reach sexual maturity. Aggression is particularly prevalent between males at puberty, and serious injury may follow if such rabbits are not separated. Bucks will spray urine and begin mounting objects, people, and other pets. It is best to neuter them early, before this aggression begins, to quell this behavior.
Does will often have intense mood swings, and they will also mount companions, spray urine, and begin digging and displaying nesting behaviors. They may become more aggressive toward people, other rabbits, and other pets. Groups of female rabbits that are bonded and have been grouped together from a young age tend to continue to get along despite hormonal changes associated with puberty. However, they should still be spayed to prevent medical problems often seen in intact females (see Chapter 17).
Rabbits will exhibit anger and annoyance with a grunt, growl, snort, or short barking sound. An upright stance will be assumed, with ears flat and tail stretched out. An angry, aggressive rabbit may also kick high and backwards and will often lunge and bite. If a rabbit nips or bites, the caregiver should respond with a short, high-pitched yip to indicate that the behavior is not acceptable. This mimics what a rabbit might do if bitten too hard by a conspecific and is therefore a response that the rabbit will likely understand.
Improper socialization and boredom can lead to aggression in rabbits. Providing for mental stimulation and exercise can help to decrease boredom (Box 39-1). Previous traumatic events may also create aggressive behaviors, and it takes time and patience for some rabbits to regain confidence and trust that they will not get hurt again. In general, animals that are well socialized and handled gently often recover from traumatic events more quickly, whereas rabbits that are poorly socialized are more likely to perceive everything as a traumatic event.
Aggression or other behavior changes that may be related to a medical problem should be assessed by a veterinarian skilled in rabbit medicine. These behaviors might include pain-related problems such as soft tissue trauma or osteoarthritis, urinary tract infections, and gastrointestinal stasis. Medical implications of abnormal behaviors and clinical signs associated with pain in rabbits have been previously reported.4,6 Failure to recognize behavior changes associated with medical problems from those that occur in response to environmental stimuli may lead to misdiagnosis and continued suffering or discomfort of the rabbit.
Territorial behaviors include aggression, as previously addressed, as well as chewing, digging, and marking behaviors. Marking is accomplished by scattering fecal pellets at perceived territorial boundaries and urinating on caregivers or their personal items or, again, at perceived boundaries. Chinning, another marking behavior, is done on objects, other pets, and people in order to mark them with secretions from scent glands, which have been found to contain different volatile components, depending on geographic location,16 and in the wild as a means of maintaining dominance hierarchies in a warren.16,17
Territorial and destructive behaviors can be quelled with surgical altering, which helps to eliminate the need to be territorial and redirecting the behaviors (see “Behavioral Training Techniques for Small Mammals,” below). Increasing the number of litter boxes and moving them to the areas where they will be most used can also be helpful (see “Litter-Box Training,” below). Remember that the rabbit may be marking his favored “person” by urinating in the clothes basket or on the bed, so this is actually a “compliment.” The only way to control it may be to keep the rabbit away from these personal items.
Chewing and digging are natural rabbit behaviors; since they cannot be controlled, the caregiver should try to divert the rabbit’s attention and provide areas that are rabbit-safe as well as offering appropriate items to dig at or chew on.9,10 Digging boxes can be created by providing a covered box with a hole in the side and filling it with shredded paper, a basket filled with hay or straw, or a cardboard box with towels in it.9
Female rabbits tend to be more prone to chewing even if they are spayed.19 Safe choices for chewing include apple, willow, and aspen branches, untreated pine lumber (molding, for example), and untreated straw baskets. These behaviors will also be seen when rabbits are bored and/or seeking attention.
Much of the behavior exhibited by rabbits is instinctive, but it may also be learned. Behavior problems are usually a temporary function of puberty and will often diminish over time unless they are reinforced by mishandling or by not being addressed at all. It is highly recommended that rabbits be neutered and spayed early in order to help to quell the natural hormonally directed behaviors previously discussed. Decreased hormonal influence on behavior after neutering will often not be appreciated for 30 days or more after altering, and it may take up to 6 months in larger breeds for negative sexual behaviors to decrease.19
It is also important to decrease confinement and increase exercise, which will help to decrease stress and anxiety15,19—often exhibited in rabbits as polydipsia, mutual and self-barbering, and carpet digging. The caregiver should provide interactive items that stimulate instinctive behaviors and decrease boredom. This can be as simple as offering a free choice grass hays, a high-fiber diet, and allowing for foraging behaviors by hiding food and treats for the rabbits to find; it can also be as elaborate as suggestions listed in Box 39-1, “Behavioral Enrichment,” which will help to stimulate the animals mentally.
Providing a consistent schedule—including feeding, exercise, and a day/night cycle—will also decrease stress-related behavior problems. By providing pet rabbits with twice yearly veterinary exams and exams whenever subtle or overt behavior changes are noted, medical issues can also be ruled out as a cause of behavioral problems.
As with children and all other species, it is important to divert their attention to acceptable behaviors9 (see “Behavioral Training Techniques for Small Mammals,” below). Rabbits are intelligent and can be very sensitive emotionally; they should be treated and respected as the individuals that they are.