Our researchers have spent the last five years carefully monitoring the hormone levels of their resident female rhinos in a bid to discover the best time to introduce them to a potential partner.
For ten years the zoo had no new baby rhinos, but since the start of the project we’ve now celebrated four births in the last four years.
But it has required scientist Katie Edwards to spend every day analysing rhino dung.
Katie, a PhD student from the University of Liverpool, said:
“Hormones associated with reproduction can be measured in an animal’s urine and faeces. So our keepers regularly bring dung samples from each of our female rhinos over to our lab for testing. We then break it down and extract all sorts of hormonal indicators from it.
“Tracking hormones gives us an insight into what is going on inside these animals. It can help tell us things like whether or not an animal is a seasonal breeder, whether it has reached puberty, whether it’s cycling on a regular basis or not and when the optimum time to introduce a male to a female is, as well as diagnose pregnancies and estimate when an animal will give birth.”
The project was devised in 2007 by the our Scientific Manager, Dr Sue Walker and Dr Susanne Shultz from the University of Manchester.
Dr Walker said:
“We established the project to try and understand the differences in reproductive success between individuals in the European zoo-based population of black rhinos – why do some individuals breed well, while others do not? The idea is that with a better understanding of reproduction, we can help to improve the breeding programme for this critically endangered species.
“Before the endocrine project was established, it was sometimes difficult to see behaviourally when a female was receptive to a male, so introductions could be difficult. But, based on her hormones, we can now predict when the best time to introduce her is and that gives our keepers that extra piece of information to help them get the timing absolutely right, hopefully increasing the chances of a successful mating.
“There had been no black rhinos born at Chester Zoo for 10 years before the programme began. Now, with its help, we have now had four births in four and half years.”
Dr Shultz added:
“Although collecting rhino dung isn’t the most glamorous work, this project is an excellent example of how academics can collaborate with conservation organisations to save endangered species. Getting a large number of zoos across Europe to contribute to science has been very exciting.”
The team is now working with zoos throughout Europe and say that their methods could transform the success of captive breeding programmes for this critically endangered species. In the wild, less than 650 now remain.
“With a species like the black rhino, where so few individuals exist, it is essential that we achieve successful breeding from as many of the rhinos in zoos as possible. To do this effectively, we need to look at the population of rhinos in zoos across the whole of Europe, not just the ones here in Chester,” said Dr Walker.
“These populations are vital as an insurance policy against further declines in the wild, and the more successful the population, both in terms of growth rates and maintaining the genetic diversity by making sure all individuals breed, the better that insurance policy can be.”