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Reports: Research into black rhinos' high male birth levels may save species

Reports: Research into black rhinos' high male birth levels may save species

New Zealand-led research that could save a rare threatened rhino from extinction may also give hope to other endangered animal species world wide, local media reported Friday.
Conservation biologist Wayne Linklater, of New Zealand's Victoria University, is heading an international project testing a theory that high sugar levels in female black rhinos are the reason disproportionate numbers of male rhinos are born.
The theory has been borne out by Linklater's research into New Zealand's Kaimanawa wild horses, and he told the "New Zealand Herald" newspaper Friday it could apply to other species.
Many captive animal species could be extinct in 10 to 15 years unless the sex imbalance can be fixed.
Linklater said extreme male-biased births in captivity are common in many species, from rhinos to zebras, gorillas and giraffes.
Some 71 per cent of black rhinos born in captivity are male, and research suggests more males are also born after black rhinos are transferred to new game reserves, he said.
Linklater said glucose levels seemed to increase in rhinos moved to zoos and game reserves.
"Glucose levels in the pregnant mothers are raised if they are stressed, fed a sugar-rich diet, and obese. This has fatal consequences, particularly for female embryos," he noted.
"It is not that more male calves are being conceived, but rather that fewer female embryos survive to be born," he added.
The rhino study was sparked by his research into Kaimanawa wild horses, which found the sex of foals was strongly related to the mother's condition at conception.
"A mother in good condition will tend to have male foals, whereas the reverse is true for mothers in poor condition," Linklater said.
"Basically it's because a son, if it's a good son, will leave many more grandchildren than a daughter. But if a mother is in poor condition ... the son is likely to fail in breeding," he said.
Scientific reviews had also suggested that glucose tends to kill female embryos, Linklater said.
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Updated : 2021-07-26 13:41 GMT+08:00