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.
Cats also have an estrous period 1-6 weeks after giving birth, so a female may be nursing one litter while pregnant with another. A cat can give birth to anywhere from 1 to 6 kittens. These kittens can start mating and producing more kittens at the age of around 6 months. A male cat can impregnate countless female.