How in vitro fertilization can save white rhinos – 01/24/2024 – Science

For the first time, scientists carried out in vitro fertilization of a southern white rhinoceros. The result offers hope that the extinction of the northern white rhinoceros, which today is down to two females, can be avoided.

“We achieved something that was believed to be impossible”, said the head of the project, German Thomas Hildebrandt, in an interview given this Wednesday (24) in Berlin, Germany.

The international BioRescue team, supported by the German government, said the procedure resulted in a successful 70-day pregnancy, with a well-developed male embryo measuring 6.4 cm in length.

The fertilization of a southern white rhino with an embryo of the same species is a “crucial advance” in helping endangered northern rhinos, highlighted Hildebrandt, who is part of the scientific group BioRescue.

In the next stage of the breeding program, scientists will try to repeat the feat with a northern white rhino embryo in a mother carrying the species very close to the south.

The reproduction program, made possible by the in vitro fertilization of oocytes by injection of frozen sperm, is the last chance for these animals to survive.

The two females of the northern white rhino species, Najin and her daughter Fatu, are very old and are no longer able to carry a pregnancy to term.

The last male, named Sudan, died in 2018 in the Ol Pejeta reserve in Kenya, where Najin and Fatu live under 24-hour surveillance, protected from poachers.

Hildebrandt’s team now aims to “produce northern white rhinos within the next two and a half years” — the process could take longer. Pregnancy in rhinos lasts 16 months.

The technology could also serve as a model for other endangered rhino species, such as the Sumatran rhino in Southeast Asia, Hildebrandt added.

Northern white rhinos, which despite their name are actually gray, used to roam freely in several countries in east and central Africa, but their numbers have fallen drastically due to hunting for their horns.

Modern rhinos have inhabited the planet for 26 million years, and it is estimated that more than a million still lived in the wild in the middle of the 19th century.