Small Mammal Behavior
Heidi L. Hoefer, DVM, Dip ABVP
Understanding basic bunny behavior is paramount to long-term owner-pet relationships. Rabbits have a natural curiosity and tendency to dig, chew, explore, and claim their territory. It is these very same qualities that make rabbits endearing as pets to those who understand them. For those of us in the veterinary profession, knowing what is normal and abnormal in terms of behavior will allow us to better evaluate a rabbit patient and provide owners with recommendations regarding health issues.
Rabbits have a relatively high water intake, averaging 50-150 ml/kg/day, and produce a large amount of urine, averaging 130 ml/kg/day. Rabbits typically urinate infrequently, but in large volumes. Changes in this pattern may reflect reproductive status, territoriality, or urogenital tract disease.
Some rabbits will urinate to mark their territory or simply because of a lack of litterbox training. Reproductive behavior can begin as early as 4 months of age in the male rabbit and slightly older in the female. Intact male rabbits (buck) will often "spray" or produce a stream of urine that is directed at the object of their immediate affection. This may be another rabbit, or the family cat or the owners leg or bedding. This type of behavior is usually reversed once the buck is castrated. Intact female rabbits have also been known to urinate inappropriately during periods of receptiveness or to mark their territory. Although they do not actually "spray", some owners complain of losing litterbox training, or jumping up and urinating on the bed or other soft materials. As in the buck, neutering often resolves most of these urination problems.
Rabbits are host to a wide array of urogenital tract problems including cystitis (bacterial or crystalloid), urolithiasis, uterine adenocarcinoma, and renal disease. Changes in frequency, volume, appearance, and location of urinations may signal a problem. Urine staining or scalding may indicate an orthopedic or neurologic problem in the patient that can't or won't move away from their site of elimination. Inappropriate or insufficient litter can also result in urine soaking of the hind quarters.
Once reproductive behavior is eliminated as a consideration, a thorough workup should be performed. The minimum data base for abnormal urination behavior includes radiographs, blood testing, and urinalysis, preceeded, of course, by a careful history and physical examination.
An assertive rabbit may "chin" or rub their chin scent glands on items that they are claiming as personal property. This behavior should be considered a benign gesture that may not abate with neutering. Some rabbits circle owners legs and nip and mount in an act of sexual aggression. A rabbit may "thump", charge, bite, snort, or violently kick when picked up. This type of behavior is often provoked and may be a fear response. It may not be immediately obvious to the owner what is inducing their rabbit to go into "attack mode" but evaluation of the household situation is often indicated. Aggression in the rabbit is most commonly caused by fear or sexual behavior. Pain is a less common cause.
Neutering may alleviate some of the aggressive behavior but not in all cases. Behavior modification can be attempted using a calm approach and positive reinforcement techniques. Keep in mind that the rabbit is a prey species and judges the world by a "will it eat me?" perspective. Rabbits do not respond to punishment and should not be hit or roughly handled. Gently pressing the head to the floor may represent dominance to a rabbit and can be used for nippy behavior in some cases.
Rabbits who are afraid or in pain may exhibit hiding behavior. (under the bed, couch, e.g.). An outgoing rabbit that suddenly displays hiding behavior should be examined and evaluated for acute pain. Differentials include gastrointestinal stasis and gas, urolithiasis, sore hocks, and orthopedic injuries.
Rabbits are chewers and are attracted to household items such as molding and other woodwork, telephone cords, carpeting, and bedding. Fur chewing is not considered "normal" unless the rabbit is pregnant or going through a pseudopregnancy. Boredom, stress, overcrowding, or lack of dietary fiber can induce barbering behavior. This must be differentiated from a reproductive fur pulling or fur chewing secondary to a pruritic skin condition (Fur mites, ear mites, ringworm, or fleas, e.g.). Fur chewing can lead to the formation of trichobezoars and gastrointestinal stasis in those on low fiber diets.
The addition of fresh hay or alfalfa cubes will increase dietary fiber and may satisfy the urge to chew. Chew toys made from cardboard boxes and rolls, untreated wood blocks, untreated wicker, and sturdy cat toys can be offered.
Some rabbits make little distinction between social behavior and sexual behavior. Running circles around owners legs, nipping and biting, digging, and spraying or marking with urine and feces are common behaviors. Neutering will often correct these actions, except in some "adolescents" that may just have to outgrow these wild tendencies. Some males and females will continue courting behavior after they are neutered and may require behavior modification training.
Ferrets are natural burrowers, "stashers", diggers, and climbers. Young ferrets are very playful and can be rough and perhaps a little "wacky" in their antics. Often termed the "weasel war dance" by endearing owners, happy ferrets can spin about wildly with back arched and teeth bared making strange hissing noises that can actually frighten unsuspecting owners!
The urinary tract of the carnivorous ferret is very similar to the dog and cat in anatomy and physiology. Most ferrets can be litterbox trained. The majority of pet ferrets are neutered very young and do not exhibit sexual urine spraying or territorial marking. In general, abnormal urinations in the ferrets is a sign of disease and not a behavioral aberration. Change in urination frequency, location, or amount produced is important information and should be specifically questioned during the office call. It may be difficult for some owners to be aware of a problem because many homes have multiple ferrets that are housed together and share litterboxes.
Ferrets that have a history of straining to urinate or defecate or dribbling out of the litterbox should be evaluated for adrenal gland disease, urolithiasis, and cystitis. The hormones that are produced by a hyperactive or tumorous adrenal gland can affect the lower urinary tract. Elevated androgens (testosterone e.g.) stimulate prostatic hypertrophy that impinges on the urethra and can also produce a secondary bacterial cystitis. These ferrets are usually mature neutered males with other clinical signs of adrenal disease (pruritis, alopecia e.g.).
Urolithiasis is common in the ferret on a poor diet. Poor quality commercial cat food with a grain-based protein source is often implicated in the formation of struvite grit, sand, or calculi in the ferret. Infection may play a role. Bacterial cystitis can also be seen the ferret and may be responsible for an abnormal urination pattern, sometimes with blood. Neoplasia of the urinary tract is rare in ferrets.
Any ferret that presents with a history of changes in urinating habits should be worked up for urinary tract disease and adrenal disease. Radiographs, blood work, urinalysis, and abdominal ultrasonography provides the diagnosis in most cases.
Aggression in the ferret usually takes the form of nipping and biting and is the most common behavioral problem seen in pet ferrets. There are many things to consider with the biting ferret: previous ownership, handling techniques and frequency, as well as possible medical causes for the aggression. It is especially important to keep rabies vaccinations up to date in these biters that may be exposed to many individuals if hospitalized (although there has never been a reported case of ferret transmitted human rabies).
Recently purchased or adopted ferrets may not have been handled or trained and may be a bit nippy. Gentle nips are natural and normal to the ferret that will often bite at other ferrets in an effort to play. Left unchecked, these playful nips can develop into painful bites. Frightened owners stop handling these biters or mistreat them and biting is exacerbated. Ferrets can be gently reprimanded with a scruffed hand (as one ferret may scruff another in a show of dominance) and a firm voice or be given a "time-out" like a child.
Ferrets can become aggressive from adrenal gland hormone overproduction. Adrenal androgens can produce sexual behavior in neutered males that is usually directed at other household ferrets, but can occasionally be directed at their humans. This type of behavior includes nipping, mounting, biting and dragging other ferrets, particularly by the scruff. Violent shaking is too excessive and should be prevented.
Deafness is seen in white-faced ("panda") or white blazed ferrets and may be similar to Waardenburg's Syndrome of people, mice, and cats. These ferrets may startle when suddenly approached and bite in defense or simply not hear their owners cries of protest. There is also a subset of blind ferrets that may also startle and bite. Retinal atrophy and cataracts occur with fair frequency in ferrets.
The final consideration for the biting ferret is pain. This is an important differential for the ferret that has always been gentle. Some ferrets may express this pain in a "lick, lick, chomp" manor which should be distinguished from the gentler "lick, lick, nip" behavior that some ferrets do normally and with affection.
Pawing at the mouth may be associated with nausea in the ferret. This can be secondary to hypoglycemic events (insulinomas), gastroenteritis (Helicobacter, viral), azotemia (renal disease), oral pain, and with some medications given per os.
Fur chewing is not a big problem in ferrets. Adrenal disease is one cause of pruritus, as well as fleas and other typical skin disorders seen in cats and dogs. Ferrets like to chew on rubber objects and these may lead to gastrointestinal impactions.
Urine licking has been noted by many owners and clinicians. The cause of this is unknown and may just be behavioral. Diabetes mellitus does not appear to play a role.
An increase in sexual behavior (often accompanied by a stronger scent) in a neutered or spayed ferret may indicate an abnormal source of hormone production. These ferrets should be screened for adrenal disease, stump pyometra or hypertrophy, or ovarian remnant.
Behavioral problems are occasionally encountered in rodents. Chinchillas, e.g., are noted for their luxurious soft coat. One of the biggest vices seen in the chinchilla is fur chewing, and like rabbits, may be due to boredom, stress, overcrowding, and lack of dietary fiber. Pseudopregnancy and ectoparasites are unusual causes of fur chewing in this species. On the large fur farms, fur chewers are culled because of the possibility of a genetic predisposition to chewing.
Biting is a big problem in some of the smaller rodents like hamsters and gerbils. Frequent handling of new juveniles will decrease this behavior. The sudden handling of sleeping hamsters (especially during the daytime) may result in a startle response that is often accompanied by a bite. Knowing the sleep-wake cycles of these different species will guide owners in appropriate times to handle these rodents.
Biting and aggression is common in the pet squirrel and prairie dog. Early neutering may help decrease this natural tendency in these species.
SOURCES OF INFORMATION
There is very little in the published veterinary literature regarding behavior of small mammals. Some other sources of information include the monthly pet magazines like Modern Ferrets (Crunchy Concepts, Smithtown, NY 516.981.3574) or Ferrets (Fancy Publications, Irvine, CA 949.855.8822) which usually have a behavior column in each issue. Pet stores and libraries often carry books on individual species that usually has a section on behavior. Species-specific clubs and societies like the House Rabbit Society (Alameda, California or www.rabbit.org) or the American Ferret Association (1-888-Ferret1 or firstname.lastname@example.org) can also be good sources of information. Another good on-line site for ferret information is www.ferretcentral.org.
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