Thursday, August 21, 2014
"Hybrid Species" (on natural interbreeding between animals in danger from climate change)
The very day I wrote my short message on interspecies relationships between animals, The New York Times Magazine published a short, but fascinating essay on animal hybridization by Moises Velasquez-Manoff, titled “Lions and Tigers and Bears.”
The article began with what seemed like perhaps somewhat innocuous information, that the increase of forested land in the US New England region had seen a remarkable resurgence of animals once perceived to be dwindling in numbers, including moose, turkeys, beavers, and white-tailed deer, the later of which are now so “numerous that they are often considered pests.”
The area has also been reinhabited by what was once called the Eastern wolf, formerly hunted and poisoned out of existence. But the new species of wolves are not precisely what they seem, but often represent an interbreed of Great Lake wolves who have long mated with local coyotes. Some of the original wolves, moreover, migrated to Canada, who bred with the eastern-pushing coyotes, and their descendants, in turn, interbred with other coyotes and dogs. The result is what some call the “coywolf,” a new breed of animal, evolved over just a few decades that have taken advantage of the pack hunting instinct and more social nature, but also, like coyotes have been able to thrive in areas around human beings.
With the increasing catastrophes of global warming and even temporary fluctuations in regional areas, it has become apparent that a number of such new species have begun to evolve, including hybrids of dolphins, fish, finches, bats, lynx, squirrels, and bears—the last creating a mix of grizzly and polar bears, whose habitat is particular endangered.
For generations the prevailing wisdom among scientists, Velasquez-Manoff asserts, was that hybridity was a “lineage-ending mistake,” often with the outcome of sterility, as in the famed case of the mating of donkeys with horses—resulting in “evolutionary duds.”
Just as Charles Darwin had argued for the increasing unpopular view of animal intelligence, so too did he devote an entire chapter in his Origin of the Species to hybrids. While 20th century scientists increasingly came to define species as the all-important distinction between animal differentiation, Darwin was not clear in his definition of precisely what a species meant: “he was vague on how to define species, referring to ‘the vain search for the undiscovered and undiscoverable essence of the term.’”
But throughout the early and mid-20th century, the concept of species became increasingly reified as the one author wrote in 1930, “the greatest blunder in sexual preference which we can conceive of.”
The New York Times Magazine author quotes geneticist Michael Arnold as suggesting that perhaps this orthodoxy with regard to animal species was related to the American attitudes about and fears of miscegenation. “Anxiety over racial ‘purity,’” writes Velasquez-Manoff, “affected how we thought about nature.”
No one yet knows precisely where these new hybrid species will lead, or whether or not hybridization will help animals threatened by human beings directly and through our transformation of nature to better survive. Will hybridization erode biodiversity, preserve it, or augment it—or effect some combination of these alternatives?
We human beings might look for an answer to our own species, who, when forced to leave the sub-Saharan African continent to move into Eurasia, sometimes mated with another related species, the Neanderthal, whose genes nearly all of us—except sub-Saharan Africans—carry today within our genes.
Los Angeles, August 19, 2014
Reprinted from Green Integer Blog (August 2014).
source: the new york times magazine, august 14, 2014