Working as a zookeeper requires you to be passionate about animals and wildlife conservation. You often spend more time with the animals than other zoo employees, getting to know their habits and personalities. This helps you determine when the animals are healthy or whether they need veterinary care, a vital role of primary caregivers.
So on average the number of days between two similar phases (e.g. between one full moon and the next full moon) is about 29.531 days. This period is referred to as a lunation, lunar month, or synodic month.
Because the time between two full Moons doesn't quite equal a whole month, approximately every three years there are two full Moons in one calendar month. The next time two full Moons occur in the same month (as seen from the United States) will be July 2015. The most recent blue Moon occurred in August 2012.