Researchers at the Smithsonian Conservation Biology Institute,a
member of C2S2, have discovered why older females are rarely
able to reproduce—and hope to use this information to introduce
vital new genes into the pool. SCBI scientists and collaborating
researchers analyzed hormones, eggs and the uteri of 34 cheetahs
at eight institutions, and determined that while the hormones
and eggs of cheetahs older than 8 years appear normal, the
animals’ uterine tracks tend to suffer from abnormal cell
growth, infections and cysts that prevent pregnancy. “Those of
us who work with cheetahs have anecdotally noted that it’s hard
to reproduce older cheetahs, but this is the first time anyone
has documented how aging affects the physiology of reproduction
in this species,” said Adrienne Crosier, SCBI cheetah biologist
and lead author of the study in which these results were
published. “We were relieved to find that, unlike in other older
mammals, the eggs in older cheetahs can produce viable-appearing
and growing embryos,