Charles River Campus: Animals Per Cage Type

Rodent Cage Capacity Policy/Minimum Cage Space Requirements (All Species)


Housing is based on the Guide for the Care and Use of Laboratory Animals and is intended to provide optimal comfort for the animals involved.


This is applicable to the rodents housed in all of the LACF animal facilities.


Exceptions to this laboratory animals policy require a written request and subsequent approval by the IACUC or the attending veterinarian. Contact the veterinarian through any LACF staff member ( or through the LACF office (617-353-5415). For any additional questions, please contact the director of LACF at 617-353-5415.


Animals at the LACF are to be housed at no more than the maximum density as outlined below for the species and type of caging.

Mice—Ventilated Cages

Number of Animals
Model: Thoren small cage with 51.7 sq. inches of floor space
Mice 4
Mom with new/young litter 1
Model: Thoren large cage with 112.9 sq. inches of floor space
Mice 8
Mom with litter 1
Model: Optimice with 75 sq. inches of floor space
Mice 5
Mom with litter 1

Mice—Static Cages

Number of Animals
Shoebox with 67 sq. inches of floor space
15+ to 25g 5
>25 4
Mom with litter 1

Plastic “Rat” Cages Both Static and Suspended, Which Have 143 Sq. Inches of Floor Space

Number of Animals
<100g 4
Mom with litter 1
100+ to 300g 4
300+ to 400g 3
400+ to 500g 2
>500g 2
Mom with litter 1
Guinea Pigs
300g or less 2
More than 300g 1

*Gerbils not covered in either the Animal Welfare Act or its regulations or the “Guide for the Care and Use of Laboratory Animals”.

For mice, rats, hamsters, and guinea pigs

Temperature: 64.4–78.8F
Humidity: 40–60%