Chris is a C57BL/6 mouse. Ordered as a dress from the catalog or a new car
part from the auto store, C57/BL is a specific type of mouse commonly used
in the SDR/SRO experiments.
Chris lives in a cage with four other mice. Looking outward from his cage,
he observes other cages
containing groups of mice.
A white coat walks into the room and Chris see a hand come out from the coat and a mouse is placed in the cage next to his. Within minutes Chris observes that the new mouse is aggressive and that fighting has started in the cage. The attack can be described as biting and chasing the mice around the cage. The mice cannot escape the aggressor.
Two hours pass and the white coat returns and removes the aggressor, now placing the mouse into Chris’ cage. Chris looks up and the intruder mouse is staring at him. Chris decides its best just to keep running and jumping in hopes of avoiding a bite. Is Chris stressed? Yes. The ordeal ends with the intruder’s removal. The white coat picks up Chris and examines him for wounds. Chris is okay but other cage mates have severe wounds to their backs and tails. One is wounded enough to warrant a quick death by the white coat.
That evening one of his cage mates seems to have gotten sick and is soon lying dead in the cage. Another day arrives and the scenario with the aggressive mouse is played out again. Chris decides that maybe today sitting in the back of cage and acting submissive will stop the attack by this aggressive mouse. When the white coat attempts the examination of Chris it is noted in the record that the mouse is hyper-responsive to handling. It is not possible to do an accurate count of the number of bites since Chris is hyperactive.
The next day after the intruder is removed all the mice including Chris are killed.
A note in the laboratory reads, “The colony was eliminated. If we happen
to miss a cage please euthanize.”
154 mice in this colony were killed with a pharmaceutical agent followed by
cervical dislocation or by inhaling CO2.
The experiment begins in another room with a new order of C57/BL mice.