We played a game to see if we could work out the different gestation periods for different mammals, including humans.  We learned that gestation is the process by which a mammal grows a baby and is the time between conception and birth.  Once we had worked out the correct gestation periods for different mammals, we were challenged to spot any patterns in the results.  We realised that there was a link between the size of the animal and how long it carried a baby for before giving birth.  

In most cases, the larger the animal the longer period of gestation.  Therefore, the smaller the animal, the shorter gestation time.