sábado, 20 de abril de 2019
Cat Experts: Ligers and Other Designer Hybrids Pointless and Unethical
Ever heard of a liger? It’s the offspring of a male lion and female tiger. There’s also the tigon, which has a lion mother and tiger father. And the leopon, the progeny of a lion and a leopard—not to be outdone by the jagulep, a jaguar-leopard mix.
Feline hybrids aren’t found in nature. Lions and tigers don’t overlap in the wild (except in India’s Gir Forest, where until now no ligers have been found). And big cats in the same territory don’t cross the species line—they’re not interested in each other, just as humans aren’t drawn to chimps.
Instead, these animals are the offspring of big cats that crossbreed in captivity and they're destined to become curiosities in zoos and wildlife parks. While it might seem fun to see one of these oddballs in the flesh, advocates of big cat conservation say this hybridization has a dark side.
“With hybrids there’s a much greater chance of the genetics being messed up,” says Luke Hunter, who heads the wild cat conservation organization Panthera. This means there’s a higher likelihood of infertility and other defects, he says.
The prevalence of these problems in big cat hybrids isn’t known: Because the animals don’t exist in the wild, scientists haven’t studied them much.
But many of the crossbreeds live healthy lives, and some have even produced offspring—a female liger in a Russian zoo mated with a male lion and gave birth to a so-called liliger in 2012.
It’s not known, either, how many of the various big cat hybrids exist, but Usman Masood, who has collected online reports of ligers and runs the website ligerzoos.com, puts liger numbers at about a hundred.
Ligers, made popular by the 2004 cult classic Napoleon Dynamite, are gold mines because of their size. The faintly striped creatures grow to about five feet tall and can weigh up to a thousand pounds, more than twice the size of their lion fathers and tiger mothers.
Reports of liger births occasionally surface from countries around the world—in late January a Russian zoo announced the birth of a liger cub named Tzar. But ligerzoos.com posits that most ligers are in private hands in the United States. Accredited zoos frown on crossbreeding big cats.
“These cats of mine are big mellow guys,” and they’re healthy, says Gregg Woody, owner of Woody’s Menagerie in Mulberry Grove, Illinois, of his two seven-year-old ligers, Hank and Charlie. Woody takes Hank and Charlie around the country as part of a traveling liger exhibit. Their size, he says, is “shocking” to people.
According to Woody, the ligers' parents spent a lot of time together and eventually mated, which scientists say can happen when a lion and tiger live in close quarters and lack other options.
“Lions are tigers are separated by about seven million years of evolution,” Craig Packer, director of the Lion Research Center at the University of Minnesota, previously told National Geographic. “But they are still closely enough related that they can hybridize.”
NO BOON TO CONSERVATION
Feline hybrids aren’t helpful to the genetic diversity of big cats and have no conservation value, says Rob Vernon, spokesman for the Association of Zoos and Aquariums, which represents 230 zoos in the U.S and a handful of other countries.
According to the association, zoos today are supposed to be arks for threatened animals and educate the public about conservation efforts. “Propagating animals that specifically do not represent the normal characteristics and variation of the species creates a confused educational message,” states the association’s policy against the intentional breeding of animals to produce rare traits.
Conservation scientist Luke Dollar says that any crossbreeding between big cat species is unethical and is the result of greed or irresponsible breeding.
“I can think of no legit excuse for a liger or tigon to exist,” says Dollar, program director for National Geographic Society’s Big Cats Initiative. “If we want to recognize and honor big cats as they naturally occur in the wild, why would we possibly experiment in these completely unnatural and not biologically founded practices?”
HYBRIDS GONE WILD
While we know that lions and tigers have yet to get frisky in the wild, it’s certainly possible for two species to produce a hybrid in nature. “Hybridization occurs among carnivores in the wild when the reproductive opportunities become really, really limited,” Hunter says.
Coywolves, the offspring of wolves and coyotes, number in the millions in the U.S. and eastern Canada. Deforestation, hunting, and poisoning of wolves in the east meant that they increasingly bred with coyotes spreading into eastern wolf territory from the U.S. Southwest.
Climate change can also have an effect. Scientists predict that melting Arctic ice will lead more than 20 marine mammals to hybridize. Already, grizzly bears moving northward into higher latitudes have been known to mate with polar bears. The result: brown-pawed, white-coated “pizzlies.”
Bibliographic Source: https://news.nationalgeographic.com/2017/02/wildlife-watch-liger-tigon-big-cat-hybrid/?fbclid=IwAR2oej0wz1Gcntx3HdXBH22DvGB5pXd1dQzglU480iNKDbcEM-4huEMb5oo
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