46 DISCOVERMAGAZINE.COM
GEORGINA GOODWIN/BARCROFT MEDIA VIA GETTY IMAGES. INSET: JAN STEJSKAL/ZOO DVUR KRÁLOVÉFLORA & FAUNA
Rhino Reboot
A rhino species on the brink of
extinction might have new life,
thanks to a novel approach to a
time-tested reproductive procedure.
Sudan, the last male northern
white rhino, died of old age at
a Kenyan sanctuary in March.
(See page 86.) That left only two
animals, both females, of his kind.
When they die, the subspecies
— which once numbered in the
thousands, roaming east and
central Africa — will be extinct.
But in July, a group of European
researchers, led by Thomas
Hildebrandt of the Leibniz
Institute for Zoo and Wildlife
Research, reported in Nature
Communications that they had
created hybrid embryos. The team
used frozen sperm from a northern
white rhino that died years ago,
and eggs from the closely related
southern white rhino. It’s the irsttime researchers have successfully
used in vitro fertilization (IVF) to
create rhino embryos.
Reproductive specialists
spent years devising a way to
perform IVF on a rhino, taking
into consideration its anatomy,
2-ton size and physiology. For
example, the team had to build
a custom probe to harvest eggs
from the rhino’s ovaries, which
are inaccessible using standard
equipment, says Cesare Galli, a
reproduction biologist involved in
the project.
By August, the team had created
seven embryos in the lab. The next
step is to implant an embryo in a
southern white, which will carry
the fetus and, hopefully, give birth
to a hybrid calf. Galli says it might
happen within three years.
Though a hybrid calf would
preserve some of the genes of thenorthern white, it won’t save the
species. That’s why researchers plan
to collect eggs from the remaining
two northern whites, Najin and
Fatu, housed at Kenya’s Ol Pejeta
Conservancy, where Sudan
died. Both females — daughter
and granddaughter of Sudan,
respectively — are infertile.
Once the eggs are harvested,
researchers will fertilize them with
northern white sperm to create
purebred embryos. A surrogate
could give birth to a northern white
in four or ive years, says Galli.
Galli hopes to use IVF on
Sumatran rhinos in Indonesia,
which number fewer than 100.
“We need to work out the details,”
he says, “but it can be done.”Sudan, who had an
armed guard detail
(above), was the
last male northern
white rhino. But
advances in IVF
tech may revive
the species (inset).