Guide for the Care and Use of Laboratory Animals - Office of ...

64 GUIdE FOR ThE CARE ANd USE OF LAbORATORy ANIMALSadditional opportunities for activity by being walked on a leash, havingaccess to a run, or being moved into areas for social contact, play, or exploration(Wolff and Rupert 1991). Loafing areas, exercise lots, and pastures aresuitable for large farm animals, such as sheep, horses, and cattle.Social Enironment Appropriate social interactions among members of thesame species (conspecifics) are essential to normal development and wellbeing(Bayne et al. 1995; Hall 1998; Novak et al. 2006). When selectinga suitable social environment, attention should be given to whether theanimals are naturally territorial or communal and whether they should behoused singly, in pairs, or in groups. An understanding of species-typicalnatural social behavior (e.g., natural social composition, population density,ability to disperse, familiarity, and social ranking) is key to successful socialhousing.Not all members of a social species are necessarily socially compatible.Social housing of incompatible animals can induce chronic stress, injury,and even death. In some species, social incompatibility may be sex biased;for example, male mice are generally more prone to aggression than femalemice, and female hamsters are generally more aggressive than male hamsters.Risks of social incompatibility are greatly reduced if the animals to begrouped are raised together from a young age, if group composition remainsstable, and if the design of the animals’ enclosure and their environmentalenrichment facilitate the avoidance of social conflicts. Social stabilityshould be carefully monitored; in cases of severe or prolonged aggression,incompatible individuals need to be separated.For some species, developing a stable social hierarchy will entailantagonistic interactions between pair or group members, particularly foranimals introduced as adults. Animals may have to be introduced to eachother over a period of time and should be monitored closely during thisintroductory period and thereafter to ensure compatibility.Single housing of social species should be the exception and justifiedbased on experimental requirements or veterinary-related concerns aboutanimal well-being. In these cases, it should be limited to the minimumperiod necessary, and where possible, visual, auditory, olfactory, and tactilecontact with compatible conspecifics should be provided. In the absenceof other animals, enrichment should be offered such as positive interactionwith the animal care staff and additional enrichment items or addition of acompanion animal in the room or housing area. The need for single housingshould be reviewed on a regular basis by the IACUC and veterinarian.Procedural habituation and Training of Animals Habituating animals toroutine husbandry or experimental procedures should be encouraged wheneverpossible as it may assist the animal to better cope with a captive environmentby reducing stress associated with novel procedures or people.