The stomach has three types of contractions: There are rhythmic, 3 per minute, synchronized contractions in the lower part of the stomach, which create waves of food particles and juice which splash against a closed sphincter muscle (the pyloric sphincter) to grind the food into small particles.
7 What is the gestation period, how many babies do they have, and when are they weaned? 1  The gestation period for rats is 19â22 days, for mice it is 17â21 days.  Rats and mice average 8â12 babies in a litter, but can have as few as 1 or as many as 20.
Both sexes can start breeding at 6 weeks of age and continue until they are about 12 months old. A females first litter often produces a smaller number of babies, as do those from female over 9 months of age. Breeding mice is an easy business as long as you remember one simple rule.That is ONLY ONE MALE TO A CAGE. have found that 2 to 4 females to one male in a standard mouse cage works fine. How many young they produce depends on their environment and breed of mice. Most pet shop mice produce small litters of about 3 to 12 babies. There are some laboratory breeds of mice that produce litters of up to 25 babies every 28 days.