The USDA Animal Welfare Act Regulations (AWARs), the Guide for the Care and Use of Laboratory Animals (the Guide), and AAALAC International require that animal housing environments allow for expression of noninjurious species-typical activities. Additionally, appropriate housing spaces or enclosures should account for the animals’ social needs – this is covered in the separate ARC Policy on Social Housing. As noted in the Guide (p. 52-3), "The primary aim of environmental enrichment is to enhance animal well-being by providing animals with sensory and motor stimulation, through structures and resources that facilitate the expression of species-typical behaviors and promote psychological well-being through physical exercise, manipulative activities, and cognitive challenges according to species-specific characteristics (NRC 1998a; Young 2003)."

As such, all animals housed at UCLA will receive environmental enrichment, unless withholding of enrichment is scientifically justified in the approved ARC protocol. In general, enrichment will be provided as described below, but may change in the future should novel opportunities and devices become known to the DLAM veterinary staff. However, any such proposed changes will be announced prior to implementation and feedback sought from investigators. With the expectation that animals will be socially housed, those individual animals that cannot be co-housed (i.e., are or become singly housed) will be provided additional enrichment of the type described in this Policy. Importantly, the additional enrichment items provided to singly housed animals will be identical to those provided under group-housed conditions (e.g. singly housed rats will receive two Diamond Paper Twists; mice will receive additional nestlets or nesting paper) as the default condition, to avoid introducing additional variables into experiments, which may impact reproducibility. Deviations from this practice (i.e. withholding of additional enrichment to singly housed animals or, conversely, routine provision of additional forms of enrichment to singly housed animals) will require description of such practice in an approved animal protocol.

Mice housed in standard or ventilated shoebox-style cages will be provided with two Nestlets [1] per cage.

Mice housed in Innovive disposable cages will receive Innorichment nesting paper [2].

Nude mice NOT housed in Innovive disposable cages will receive Bed’r Nest paper [3].

Breeding mice may receive disposable or plastic mouse huts [4] instead of, or in addition to, enrichment described above.

Rats will be provided with one Diamond Paper Twist [5] per adult rat.

Birds will be provided perches, nesting boxes, mirrors, foraging materials or other forms of species appropriate enrichment as determined in consultation with the investigator.

For all USDA-covered species (e.g., pigs, dogs, NHPs, rabbits, and any other warm-blooded animal with the exception of mice of the genus Mus, rats of the genus Rattus, and birds), environmental enrichment and exercise, if required, will be conducted in accordance with the standards of the AWARs and relevant DLAM Standard Operating Procedures (SOPs) and in consultation with the investigator. Enrichment may include housing with compatible conspecifics and provision of food treats, "toys" (e.g., plastic chain, balls, Kong toys, food puzzles, forage boards), and hiding places.

Investigators are encouraged to develop and utilize forms of enrichment (e.g., plastic tubes or nesting huts for rodents, or music/television viewing for non-human primates) in addition to the standard methods described above. Alternative methods may be implemented on a trial or case-by-case basis following consultation with a DLAM veterinarian; routine use of additional or alternative means of enrichment should be described in the approved research protocol.

[1] Lab Supply Nestlets
[2] Innorichment Nesting & Enrichment Sheets
[3] The Andersons Lab Bedding
[4] Shepherd Specialty Papers
[5] Envigo Research Models and Services

Approved 3/28/05 ; Revised 11/14/05, 11/27/06, 3/28/11, 2/13/12, 1/12/15, 1/23/17, 9/24/18, 1/8/24