Tips on care and handling

Most wild–derived inbred mice are hyperactive and require special handling. Problems associated with receiving them and establishing a breeding colony can be reduced by following the guidelines outlined below.

Upon Arrival: Unlike most common inbred mice, which try to run from light, some wild-derived inbred mice run toward light, presumably associating it with an escape route. So, be careful when removing them from their shipping containers:

  • Have a new cage and forceps ready to facilitate picking them up as the shipping box is opened.
     
  • Place the entire shipping container in the bottom of a sterilized garbage can or other deep container. Escapees are much easier to catch if contained. Alternatively, place an extra cage lid over the opening of the shipping container. As you open the container, slide the lid into place over the opening and maneuver it as needed to create smaller openings from which to remove the mice.
     
  • Some wild–derived inbred mice tend to burrow in bedding, making the shipping container appear empty. Verify the number of mice shipped (indicated on the container) with the number received and check the bedding thoroughly for any burrowing mice. 

Colony Care: Once wild–derived inbred mice are in your animal facility, inform ALL animal caretakers involved in their care of the following:

Wild-derived inbred mice are more sensitive than common inbred strains to stresses associated with shipping, new surroundings, and new handlers. Pairs should be housed in a quiet room, away from areas of heavy traffic and noise. They should be handled as little as possible (this includes moving the entire cage). Animal caretakers should allocate enough time to work slowly and patiently when changing their cages, weaning them, etc. We recommend handling all wild-derived strains with forceps: they do not traumatize the mice as much as do human hands, and, more importantly, do not deposit human scent on newborn pups (human scent may induce a mother to cannibalize her litter). If you must handle the mice directly, use a clean pair of disposable gloves, and change gloves between cages.

Allow 8-12 weeks for a pair of wild-derived mice to settle down and produce a litter. If the pair does not produce after this time, place a different female in the male’s cage. When six to eight weeks old, males may fight. If this becomes a problem, either place the males alone in cages or pair them with females. Fighting is particularly prevalent among mice of the CZECHII/Ei strain and progeny from any crosses involving Mus musculus castaneus.

To decrease the incidence of cannibalism, avoid changing a cage if it contains a litter less than three days old. If cages containing newborns must be changed, the nest and pups should be moved as a unit using a gloved hand.

Placing either Nestlets or Kimwipes® in a cage often encourages nesting, improves overall productivity, and provides environmental enrichment.

If, despite all measures taken to improve the environment, a female develops a history of either abandoning or cannibalizing her litters, fostering litters to another female is usually the best alternative. See Fostering information for Inbred Mice.

For details on wild-derived nomenclature, consult the "Interactive tutorial on mouse nomenclature."