There were fewer than 100 southern white rhinoceroses (Ceratotherium simum simum) a century ago. Today, there are over 20,000. Sadly, this success story only stretches as far as the southern subspecies of the white rhino. With the death of the last male in 2018, the northern white rhinoceros (Ceratotherium simum cottoni) has passed the point where it can be saved naturally. With only two females remaining, the subspecies is now classed as functionally extinct.
This is a poignant, but not entirely hopeless, situation. New techniques, such as in vitro fertilisation (commonly known as IVF), enable us to bypass normal reproduction to produce new northern white rhino babies. Sperm samples from deceased males that are preserved in bio-banks solve one side of the equation, but there aren’t frozen stores of northern white rhino eggs that we can rely on as easily.
We established the Rhino Fertility Project at the University of Oxford to help solve this problem. By using ovary tissue from deceased female rhinos to grow lots of eggs for fertilisation in a lab, we think we may have found a way to save the northern white rhinoceros – and potentially, other endangered species – from extinction. MORE
Header image: How oocytes in follicles can develop into offspring by using in vitro ovarian tissue culture. Credit: Ruth Appeltant, Author provided.