Towards the end of 2012 Chester Zoo had plenty of reasons to celebrate. We saw the most prolific period for mammal births in our history! There was the arrival of the zoo’s first ever okapi, as well as an Eastern black rhino, Rothschild’s giraffe and two Sumatran orangutans.There’s a lot more to breeding than just good luck! These new arrivals were down to real team work and years of planning – excellent husbandry and science to back it all up. One unit involved in helping achieve this landmark breeding success was our endocrinology team. The black rhino birth meant another step towards sustaining a black rhino population which, in the wild, has been ravaged by poachers. The birth of the zoo’s first ever okapi, a female called Tafari, was another great milestone in our history.