Space Recommendations
BACKGROUND
The Guide for the Care and Use of Laboratory Animals (the Guide, NRC 2011) lists the minimum space recommendations for laboratory animals. Some of the issues addressed are as follows: "Singly housed animals may require more space per animal than that recommended for group-housed animals, while larger groups may be housed at slightly higher densities." (p.58) "When selecting a suitable social environment, attention should be given to whether the animals are naturally territorial or communal and whether they should be housed singly, in pairs, or in groups. An understanding of species-typical natural social behavior (e.g., natural social composition, population density, ability to disperse, familiarity, and social ranking) is key to successful social housing." (p.64) Population density can affect reproduction, metabolism, immune responses and behavior. Group composition should be held as stable as possible as mixing groups or introducing new members can alter behavioral and physiological functions. Larger animals may require more space to meet the performance standards.
The Guidance on Prompt Reporting to OLAW under the PHS Policy on Humane Care and Use of Laboratory Animals (PHS/OLAW NOT-OD-05-034) states as an example of reportable situations the following: "Chronic failure to provide space for animals in accordance with recommendations of the Guide unless the IACUC has approved a protocol-specific deviation from the Guide based on written scientific justification."
IACUC Policy
Compliance with the following guidelines is required unless written exception has been approved by the Wayne State University Institutional Animal Care and Use Committee (IACUC) on the grounds of accomplishing scientific objectives. Divergences from this policy should be discussed with the veterinary staff. NOTE: For animals that are not listed below, contact a veterinarian.
Table 1. Recommended Minimum Space for Mice and Rats Housed in Groups (the Guide, p. 57)
| Animal | Weight (g) | Floor Area/Animal (in2) | Height (in) |
|---|---|---|---|
| Mice | <10 | 6 | 5 |
| 10 - 15 | 8 | ||
| 15 - 25 | 12 | ||
| >25 | ≥15 | ||
| Female + litter | 51 | ||
| Rats | <100 | 17 | 7 |
| 100 - 200 | 23 | ||
| 200 - 300 | 29 | ||
| 300 - 400 | 40 | ||
| 400 - 500 | 60 | ||
| >500 | ≥70 | ||
| Female + litter | 124 |
Table 2. For standard caging used by DLAR these recommendations translate into the following examples
| Animal/Cage Type | Cage Size (in2)* | Maximum Number of Animals |
|---|---|---|
| Small mouse static microisolator cage | 67 | 5 mice <25g |
| 4 adult mice ≥25g | ||
| 2 adult mice with one unweaned litter | ||
| Small mouse ventilated cage | 77 | 6 mice <25g |
| 5 mice ≥25g | ||
| 2 adult mice with one unweaned litter | ||
| Large mouse static | 144 | 11 mice <25g |
| Microisolator cage and Large mouse ventilated cage: Allentown (Purple) |
140
| 9 mice ≥25g |
| 3 adult mice with two unweaned litters** | ||
| Rat microisolator | 143 | 6 rats <200g |
| 4 rats <300g | ||
| 3 rats <400g | ||
| 2 rats ≥400g | ||
| 1 adult rat with one unweaned litter | ||
| Rat ventilated cage | 140 | 6 rats <200g |
| 4 rats <300g | ||
| 3 rats <400g | ||
| 2 rats ≥400g | ||
| 1 adult rat with one unweaned litter | ||
| Suspended wire/metabolism cage | 66 | 1 rat <500g |
*Cage size determined by measuring length and width of a cage at the level of the surface of the bedding.
**A breeding trio consists of 3 adults (1 male and up to 2 females with nursing litters)
Table 3. Space recommendations for Guinea Pigs (the Guide, p. 57; Animal Welfare Regulations)
| Cage Type | Weight (kg) | Floor Area/Animal (in2) | Height (in) | DLAR Enclosure Area (ft2) | Max # of Animals/DLAR Enclosure |
|---|---|---|---|---|---|
| Ancare Microisolator | <350 | 60 | 7 | 144 | 2 |
| ≥350 | ≥101 | 7 | 1 | ||
| Female w/ pups | 101 | 7 | 1 | ||
| Lab Products | <350 | 60 | 7 | 210 | 6 |
| ≥350 | ≥101 | 7 | 3 | ||
| Female w/ pups | 101 | 7 | 3 | ||
| Lab Products | <350 | 60 | 7 | 368 | 6 |
| ≥350 | >101 | 7 | 3 | ||
| Female w/ pups | 101 | 3 |
Table 4. Space recommendations for rabbits (the Guide, p. 59)
| Animal (Rabbits) | Weight (kg) | Floor Area/Animal (ft2) | Height (in) | DLAR Enclosure Area (ft2) | Max # of Animals/DLAR Enclosure |
|---|---|---|---|---|---|
| Allentown standard cage | <2 | 1.5 | 16 | 5 ft2 | 3 |
| 2 - 4 | 3 | 1 | |||
| 4 - 5.4 | 4 | 1 | |||
| >5.4 | ≥5 | 1 | |||
| Allentown extended cage | <2 | 1.5 | 16 | 10 ft2 | 6 |
| 2 - 4 | 3 | 3 | |||
| 4 - 5.4 | 4 | 2 | |||
| >5.4 | ≥5 | 2 | |||
| Alternative design standard cage | <2 | 1.5 | 16 | 6 ft2 | 4 |
| 2 - 4 | 3 | 2 | |||
| 4 - 5.4 | 4 | 1 | |||
| >5.4 | ≥5 | 1 | |||
| Alternative Design expanded cage | <2 | 1.5 | 16 | 12 ft2 | 8 |
| 2 - 4 | 3 | 4 | |||
| 4 - 5.4 | 4 | 3 | |||
| >5.4 | ≥5 | 2 |
Table 5. Space recommendations for other animals (the Guide, p. 59, 62)
| Animal | Weight (kg) | Floor Area/Animal (ft2) | Height (in) | DLAR Enclosure Area (ft2) | Max # of Animals/DLAR Enclosure |
|---|---|---|---|---|---|
| Cats | ≤4 | 3 | 24 | 3' x 1.8' , 5.5 | 1 |
| >4 | ≥4 | 24 | |||
| Dogs | <15 | 8 | Able to stand erect | 6' x 4' , 24 | 3 |
| 15 - 30 | 12 | 2 | |||
| >30 | ≥24 | 1 | |||
| Swine 1/enclosure | 15 - 100 | varies | Able to stand erect | a) 6' x 4' , 24 b) 2 adjacent contiguous pens, 48 | 1 |
| 100 - 200 | 48 | 1 swine in 2 contiguous pens | |||
| >200 | ≥60 | Not allowed | |||
| Sheep and Goats 1/enclosure | <25 | 10 | Able to stand erect | a) 6' x 4', 24 b) 2 adjacent contiguous pens, 48 | 4 |
| 25-50 | 15 | 3 | |||
| >50 | ≥20 | 2 | |||
| Sheeps and Goats 2-5/enclosure | <25 | 8.5 | Able to stand erect | a) 6' x 4', 24 b) 2 adjacent contiguous pens, 48 | 5 |
| 25-50 | 12.5 | 3 | |||
| >50 | ≥17 | 2 |
Table 6. Space recommendations for aquatic species (the Guide, p. 83)
| Animal | Weight (kg) | DLAR Enclosure/water requirements | Max # of animals/DLAR Enclosure |
|---|---|---|---|
| Zebrafish* | NA | 5 adult fish per L water 20 eggs or larvae per 100 mL | Varies |
*Matthews M, Trevarrow B, Matthews J. 2002. A virtual tour of the guide for zebrafish users. Lab Anim 31:34-40.
Approved: December 2012
Revisions Approved: March 2013, June 2013, September 2015, April 2016, June 2018, April 2022, March 2023