How does the body register time e.g. a human’s gestation period is 9 months, a dog’s is 8 weeks. How does the body

Question: How does the body register time e.g. a human's gestation period is 9 months, a dog's is 8 weeks. How does the body register this?
- Keywords:
  body clock,
  circadian,
  rhythm
Asked by to Del, Catherine, John, Mo Rassul on 19 Mar 2014. This question was also asked by .
- Adelle Thrower answered on 19 Mar 2014:
  
  I’m not entirely sure to be honest- but I would think it has got a correlation of size. The smaller the mammal the shorter the gestation. For example elephants take two years whereas a mouse is 19 days.
- John Foster answered on 19 Mar 2014:
  
  The cells in our body have an internal clock called circadian rhythm. This is linked, in part, to the light and dark of day and night. The circadian rhythm can affect lots of things in our bodies including our brain waves and the chemicals that our cells produce. However, I am not sure how this is linked to gestation periods

Question: How does the body register time e.g. a human's gestation period is 9 months, a dog's is 8 weeks. How does the body register this?