Methods of Pairing and Pair Maintenance of New Zealand White Rabbits (Oryctolagus Cuniculus) Via Behavioral Ethogram, Monitoring, and Interventions

The overall goal of this process is to present effective methods for establishing newly paired New Zealand white rabbits, as well as a behavioral ethogram and strategies for successful paired maintenance. This method can help answer key questions in the rabbit social housing field by clearly defining behaviors characteristic to paired laboratory rabbits and defining what those behaviors indicate. The main advantages of this technique include methods for successfully pairing female laboratory animal rabbits in a cage setting and also strategies for successful maintenance of both male and female rabbit pairs.

Generally, individuals new to this method will struggle, because we are instinctively inclined to immediately separate any animals engaging in aggressive behavior. However, some agnositic displays are necessary for rabbits to successfully establish their dominance hierarchy. If we intervene too quickly, we disrupt this process, which can delay or prevent the creation of a successful pair.

Visual demonstration of this method is critical, as behaviors noted during pairing and pair maintenance can be difficult to learn without direct observation and can appear as fight behaviors when they're actually normal means of social communication. When female NZW rabbits arrive from vendors unpaired, use the following protocol to pair them. First, collect fresh urine from a male rabbit.

Overturn the liner underneath its cage so that the plastic side is facing up and the urine pools on the top of the liner. Then, syringe off the urine and store in sterile conical tube. Next, prepare a clean, neutral cage without a center divider.

Include at least two low value enrichment items, such as toys or chew sticks, and include two high value destructible enrichment items. Include at least two hideouts, such as a perch, hut, or box, and importantly, include two separate access points for food and water and two separate piles of loose hay. Now, unpack the first female from the shipping container, weigh her, and trim her nails.

Then, if needed, mark the rabbit on the tips of the ears with blue or purple nontoxic animal safe ink for individual identification. Next, using a gauze pad or cotton ball, apply approximately one milliliter of the buck urine to the rabbit's forehead and place her into the neutral cage. Then, prepare another female in the same manner, but without the earmark and place her in the same cage.

Now, monitor the pair continuously for at least an hour while filling out the rabbit social introduction log. Record each behavior observed at each time point. When biting or fighting behaviors occur, intervene with a squirt of water from the spray bottle.

Also use the spray bottle if both rabbits are chasing each other for over 15 seconds, but not if one of the rabbits is fleeing, which is a normal behavior. If intervention is needed, then temporarily separate the rabbits and check each for wounds. If there is any wounding near the eyes, genitals, or any actively bleeding wounds, then do not reintroduce the pair and promptly notify veterinary personnel.

If the pair is stable after one hour of observation, then make two more 10 minute observations later in the day. If the pair is still behaving aggressively, continue monitoring them for another hour and reevaluate. If the pair requires multiple interventions and are continuously engaged in aggressive behaviors, increase monitoring and intervention and watch closely for any wounding.

If the pair is stable during the two 10 minute checks, leave them paired overnight, and on the following morning, give each a rabbit a physical exam to check for wounds, especially around the genitals. If no wounding is observed, perform daily 10 minute checks for the remainder of the week. If the pair is maintained for a week, then consider the pair stable.

Pairs are considered a failure if they demonstrate specific types of wounding, as outlined in the text, or if they are unable to stay together overnight without continuous new minor lesions occurring within one to two weeks. Other pairs can be created using the same method, including female sibling pairs at weaning, female non-sibling pairs within a week after weaning, female weanlings with their mother, male siblings at weaning, or adults that were purchased pre-paired from the vendor. For these types of pairings, a quick five minute observation is all that is needed to ensure a compatible pair.

When filling out the social housed interaction and enrichment log, there are a wide variety of behaviors to be familiar with. Several of these affiliative behaviors, and others, are positive indicators of pairing. The establishment of a clear dominant and submissive animal is affiliative.

These behaviors include one rabbit chasing, mounting, chin marking, or thumping, while the other accepts the behavior submissively. Sharing resources, such as food, water, and hay, is a positive indicator of pair stability. Another positive behavior is allogrooming, in which one rabbit grooms the other.

If the submissive grooms the dominant, this is not a sign of pair breakdown. Observations of self-grooming are also positive. This indicates that the rabbit feels secure in the shared environment.

If the two are sharing space or choosing to be in the same location, this is also positive. Another positive behavior is when a rabbit is engaged alone with an enrichment item, or when the pair is interacting with environmental enrichment items together in a non-aggressive, non-competitive manner. When making an observation, note that if no interactions are seen, this is considered a neutral outcome.

This does not indicate incompatibility per se, but if the rabbits consistently ignore one another, it could suggest a dominance hierarchy has not yet been established and a high potential for negative behavior. Negative behaviors include fighting or an inability to establish a dominance hierarchy. Fight behavior is defined by both animals performing negative behaviors at the same time, such as the two rabbits circling or chasing each other.

Rabbits were examined by veterinary personnel after these altercations and no wounding was observed. Watch closely for biting, wounding, circling, resource guarding, or lunging. When any of these behaviors are observed, intervene with a squirt of water from the spray bottle to distract the rabbits from the behavior.

Typically, the rabbits will separate to opposite sides of the cage to groom the water off of their fur. If the water does not cause them to disengage in negative behaviors, put on a pair of heavy gloves and manually separate the pair. There are a variety of natural ways that rabbits use to communicate their dominance hierarchy with each other.

When observing these behaviors, place the pair on an increased monitoring status, and for intervention, provide high value enrichment items. Chasing and fleeing are very common in pairs establishing dominance and this behavior does not warrant intervention. Urine spraying is most frequently seen in paired adult males, but can be observed in paired females.

Urine may be sprayed on the cage or on the submissive rabbit. Both rabbits have observable urine staining on their fur, as well as on the cage. This pair consists of two adult males, 1.6 years old, who have a stable and well-established dominance hierarchy.

The pair is often observed demonstrating mounting, urine staining, grooming, chase flee behaviors, allogrooming, as well as laying together. The urine staining is under close and continuous monitoring and neither male has demonstrated skin irritation or lesions as a result. Mounting is a very typical dominance display, with the dominant mounting and the submissive accepting.

Barbering, hair loss as a result of overgrooming by a cagemate is usually first observed on the nose, in between the ears, or on the back of the neck. Monitor this to ensure it does not progress to lesions. This rabbit has observable facial barbering and is under continued monitoring, but has developed no lesions as a result of the barbering.

Thumping is done for multiple social communication reasons, one of which is to display dominance. But it might also be sign of submission when accompanied by fleeing. Over a 12 month period, 344 NZW rabbits, 62%of which were female, were paired as described.

Of these pairs, only 8%were separated for aggression. The separated pairs were 18 1/2 weeks old on average and only two rabbits had wounding that impacted their utility for further investigations. At the time of separation, for research purposes, the oldest male pair was 75 weeks old, and the oldest female pair was 92 weeks old.

Neither pair were wounded and both performed affiliative behaviors. After watching this video, you should have a good understanding of how to create new rabbit pairs, what behaviors to monitor to maintain successful pairs, and how to properly intervene to help a pair sustain a healthy dominance hierarchy. Rabbits can significantly benefit from social housing.

As with all socially housed animals, wounding is possible, so all pairing activities should be closely observed by trained personnel with close veterinary oversight. Any lesions should be promptly reported to veterinary personnel.