Skewed sex ratio plagues Visakhapatnam zoo

VISAKHAPATNAM: The Indira Gandhi Zoo Park (IGZP) is facing a peculiar problem -a skewed sex ratio. The males of species like lions, rhinoceros, bisons and birds have no female partners for company , affecting the breeding at the zoo.
There's either no female substitute available after death or more males of the species are being born, which is making it an uphill task to provide female partners for some animals.Even attempts of the zoo authorities to import females from other zoos have come to naught due to a shortage there as well.
Zoologists attribute this skewed sex ratio to multiple factors such as environment or climate change, genetic reasons, stress or hormonal changes and impact of steroids or drugs. However, all these need an in-depth research, authorities said.
“We need two female lions as we have two males. We have requested a zoo in Gujarat to send us a couple of female Asiatic lions but we are not yet sure of their arrival. Even Nakul the rhino, who was shipped in from Kanpur a couple of years ago, is all alone in his enclosure.The birth rate of rhinos in general is very low in India and the number of females are even fewer. Again, we recently had four bisons delivered, out of which three are males.Even in birds, we need more pairs, especially female ones,“ said IGZP curator G Ramalingam.
Zoology expert Prof D E Babu, who is also the chairman of the Board of Studies at Andhra Univer sity's zoology department, listed a number of causes for this lopsided birth of more males. “Temperature changes and mating season invariably influence the sex of the babies.In some species, warmer temperatures can result in more male births and vice-versa, but more research is required in this field,“ he said.
“Hormonal or stress factor also impacts pregnancy and sex of the newborn. It has been proved that species like fish change their sex when under stress. Male vigour is another triggering factor. If there are more males present in the confined atmosphere and they dominate, the chances of the mother giving birth to more male offsprings is higher. If more androgen (male hormone) is released into the environment by the animals, the birth of more male babies can be expected. Besides the type of nutrition taken and administration of specific drugs or steroids during pregnancy can also determine the sex of the babies,“ added the zoologist.
As for other developments at the zoo, the Hudhud-battered butterfly park is likely to commence in a month or two. The pygmy hippos and zebra, that were supposed to arrive from Sri Lanka and Taiwan respectively , are still awaited. “They are still abroad and awaiting quarantine certificate from the Indian government,“ said Ramalingam.