Mice not Easy to Produce in Classroom

The AP environmental science class at Penn Manor has one project in particular that requires more effort than thought, breeding mice.

A group of three students received ten mice earlier in the school year, four males and six females.  They placed two females and one male in two cages, and the other two cages had one male and one female.

They figured in no time at all, there would be a lot more.  Little did they know, it was not going to be as easy as one, two, three.

All of the cages were given the necessities including houses, wheels, and tubes to play with, and of course the bedding.

“One time we weren’t able to locate one of the mice and it turns out it was buried in the bedding sleeping,” said Spencer Barnett, one of the group members.  “They seem to either bury in the bedding or hang in the houses to sleep.”

The students researched the key factors of breeding after they had the mice a few days and discovered the complexity of the project.

Breeding mice is unexpectedly difficult. Photo by understandinganimalresearch.org.uk

A mouse is mature by the age of 5-8 weeks, according to the Transgenic Mouse Facility.  It’s preferred that females are not bred until 8-12 weeks so that the pups arrive healthy.  Once of age, they are put in with one male, because if two or more males are in the cage with a female that is pregnant, the female will abort their babies to be with the alpha male or they will try to kill each other.

On the other hand, a female’s gestation period is 19-21 days, and every 4-5 days they have their estrus cycle.  When the babies are born, it is important to separate the male from the babies so none of the babies are eaten.  At three weeks they’re weaned or separated by sex in groups of five and the process is repeated, according to the students’ research.

But all the research and planning does not guarantee success.

The mice were kept in the room next to Sally Muenkel’s so that the stench of them wouldn’t be too noticeable.

“After a week, the smell was gagging us so we cleaned the cages out and found two dead carcasses of mice.  That was not a pretty sight,” explained Barnett.

The project is to breed the mice so that Erick Dutchess’ pet snake, Rex, has a continuous supply of food.

The group got their ten mice near the beginning of the year and had some difficulties keeping them alive.

Due to the mice eating each other, dying, and one supposedly escaping, their ten dwindled to three.  Four were added to the three to make seven in hopes of succeeding.

The mice were forced to move to the greenhouse outside of Dutchess’ room where hopes were smashed and the seven mice quickly fell to two, one female and one male.

The students left for the long weekend giving them a clean cage, fresh water, and fresh food, the best habitat for them to survive.

Tuesday following the long weekend, the mice were checked on and unfortunately both were found deceased.

“I was so excited to get these mice thinking that we would get babies.  When I saw that our project was a complete failure, I was not happy with our results,” said Jesse Graham, another group member.

Now, the students need to do a report on the whole experience, which had few successful aspects and no baby mice to continue the supply of food.

It’s up to the next group to prove their skills in breeding mice.

By Cree Bleacher