Given that humans are at least a “3 way” between neanderthals, denisovans, and cro magnon species, I think this has been going on for a long time. Given that polar bears evolved from brown bears (think Grizzly) they, too, have been ‘crossing’ for a very long time. But never let the truth get in the way of a good scare storey. From a magazine that at one time covered Science, but now just does political scare stories, we have:
Global Warming Spawns Hybrid Species
Call it the “grolar bear” dilemma: Are hybrids caused by climate change bad for species?
By Manon Verchot and ClimateWire | June 1, 2015
But closer analysis of genetics suggests that perception is far some settled. What is clear is that warming is increasing many opportunities for gene mixing.
“As we’ve developed genomic methodologies, we’re finding that organisms are exchanging genes with other species,” Arnold said. “Genetic exchange due to organisms coming together from climate change is the rule rather than the exception.”
Animals have been interbreeding for millennia. Even modern humans are the product of genetic exchange with Neanderthals some 60,000 years ago.
But the rate at which species interbreed is accelerating because of climate change, researchers say. As habitats and animal ranges change and bleed into one another, species that never before would have encountered one another are now mating.
So they have finally discovered that the “species barrier” is more of a species strong suggestion? Others have known this for decades to centuries. They also have this caption under a picture of the wolf-dog-coyote hybrid:
A coyote-wolf-dog hybrid that made its way to western New York in the 1940s has the combined features of stealthy coyote-like movements and a larger skull, making it better-adapted to hunting white-tailed deer.
So right there in their own article they point out the hybrid that leads to humans was 60,000 years ago (and maybe some more recent that they do not mention) and the case they showcase is from before the 1940s (since it was showing up then, the cross had to happen earlier). Both of these well before significant human derives CO2 was in the air, and before the “new little ice age scare” of the ’70s. Their own evidence shows it is not at all heat related. But they press on.
Warmer temperatures have allowed grizzly bears and polar bears to venture to habitats they don’t usually occupy and mate to form a hybrid: the pizzly or grolar bear.
Similar trends have been observed between golden-winged warblers and blue-winged warblers.
“This issue is horrendously complex because of our ability to change the environment,” said Arnold.
Considering that human activity has indirectly brought together species through planetary warming and increased fossil fuel emissions, the question on the minds of many biologists like Arnold is whether humans should play a role in preventing hybridization like this.
Polar bears and grizzly bears have been face to face and belly to belly forever. The Polar Bear is derivative of the Brown Bear (Grizzly) and the polar bear habitat begins where the brown bear starts to taper off. These too have been doing the bear dance for a very long time. That is part of WHY they can cross so easily.
While this article asserts it is very rare and behaviour keeps the two species separated, it then goes on to cite all sorts of evidence for frequent encounters and crossings. Go figure…
Posted: Sunday, April 7, 2013 12:00 am
Ned Rozell / Alaska Science Forum
FAIRBANKS – When he heard the news of a grizzly-polar bear hybrid shot in Canada’s Arctic last month, Tom Seaton thought back to an unusual polar bear hide he’d once seen at Nelson Walker’s home in Kotzebue.
“He had two polar bear rugs in his house — one was a huge one, and the other was special; it had lots of brown in it,” Seaton said. “It looked like a regular polar bear, but for every square inch of hide, 5 to 20 percent of the hairs were brown instead of white.”
Walker, who has since passed on, was a polar bear hunting guide in the village; Seaton was then a teenage hunter who loved to listen to Walker’s stories. He’s now a biologist with the Alaska Department of Fish and Game in Fairbanks. Because he had heard that polar bears and brown bears had bred successfully in a zoo, Seaton was pretty sure Walker’s white-and-brown hide was from the mating of a polar bear and a brown bear.
So an adult, back when he was a kid, saw a hybrid rug that had been there who knows how long. But certainly before the recent spike up in CO2 and likely just about that “new little ice age scare” of the ’70s.
UAF scientists doing genetic testing about a decade ago found that grizzly bears may be the ancestral fathers of polar bears, which over many thousands of years perhaps evolved to life on sea ice by developing all-white coats, furry feet, and teeth designed to rip seal flesh. People sometimes see the two bears together at whale carcasses, such as at a bowhead whale boneyard outside Kaktovik, where in fall both polar and grizzly bears feast on the remains of whales harvested by villagers. Those who have seen the bears there say that the grizzlies, often smaller than the polar bears, dominate the encounter.
“They are two very different animals as far as behavior goes,” said Geoff York, a polar bear researcher at the USGS Science Center in Anchorage. “When a brown bear comes in at the bone pile, it chases off all the polar bears.”
Dick Shideler, a biologist at the Alaska Department of Fish and Game in Fairbanks who studies the farthest-north grizzly, has documented grizzly bears on the sea ice north off Alaska’s coast.
“We’ve radio collared a grizzly bear who hunts seals in the spring,” Shideler said. “Our pilot has tracked him on the ice, going from hole to hole. He’s figured it out.”
Shideler also said biologists from the Northwest Territories have in the past shared reports of what could have been hybrid bears.
“There was a grizzly up there towards Banks Island that killed a bunch of seals, and (a pilot) tracked it and saw its tracks intersecting with those of a polar bear,” he said.
The carpet of tracks on the snow looked like the bears could have mated, Shideler said.
“The next year a helicopter pilot saw a female with darker cubs,” he said. “And (hybrids) have been reported quite a few times by Natives (of Canada’s Arctic).”
Biologists don’t think “grolar bears” could outcompete either species; a hybrid probably wouldn’t forage on land as well as a grizzly bear, and a mottled brown coat wouldn’t be the best camouflage on sea ice.
Quite simply, they are “kissing cousins” and while they are somewhat specialized, each can work the other turf if needed and they are quite happy to recognize each other as bears.
The SciAm article goes on:
A threat to genetic diversity?
Montana’s Flathead Basin has long been a spawning haven for the westslope cutthroat trout. But as waters in the region warm, rainbow trout have swum up from the western lakes where they were introduced decades ago to cutthroat native grounds.
As rainbow trout meet and interbreed with dwindling cutthroat trout populations, the survival of cutthroat trout is at risk. Instead, a hybrid species is taking its place.
Now I personally remember the cutthroat being endangered by the introduced by government rainbow trout from back in the ’70s. It was cold then. Cold enough folks were hawking a New Little Ice Age scare. Snowed in my home town then (twice) and that was a “once in a lifetime” event there.
At the time, cutthroat reduction was simply attributed to an alien introduced species migrating from where it was stocked into the tributaries. All sorts of lesser California native trout have been so impacted. Some via rainbows eating their fry. Others via food competition. And others still from hybridization and swamping. (How do you compete with an infinite sized gene pool for the invader as they are still being stocked?…)
So to me this just stinks of “rebranding” a government perpetrated stupidity as “Global Warming” by the warm-mongers.
Now, don’t get me wrong, I also remember in the ’60s going fishing for trout with my Dad in the Sierra Nevada mountains. We caught some brook trout, and in the larger streams, some cutthroat (they have a distinctive red line along the gill plate near the ‘throat’). But the big prize was the larger, stronger, and more “fight in them” rainbow trout (named for a rainbow like swath of colors on the side). Even then, there were a couple we caught that were a bit hard to decide just what they were… I liked the cutthroat as an interesting trout that was tasty and frankly, didn’t mind that they were easier to catch with less ‘fight’. I don’t particularly want them to be wiped out.
But at the same time, “trout is trout”. Once in the pan and on the plate, I can’t tell them apart. They are all salmonids, and they have a pretty easy time crossing. Given any geologic scale time period, species change and evolve. Modern humans only came into existence a million years or so ago (and the oldest start of pre-humans is about 6 million years back). In another million years it is highly unlikely that “humans” then will be humans as we know them. Or that the trout will not have changed too.
It is an incredible fool’s errand to think you can take 4 Billion years of evolution and freeze it at a moment in time. The whole process is set up to encourage change and adaptation so that survival of the lineage continues. IFF that red throat mark confers some kind of advantage, the hybrid will evolve back that way. If the rainbow markings are an advantage, the other way. If it is just a minor decorative difference, then who cares? Apparently not the fish, who think each other acceptable partners.
Even before that much time passes, we have at most 2000 years to the next glacial. Potentially it can happen as soon as a couple of hundred years (and we might be in the entry to it now, but it is hard to tell as geological scale things happen so slowly). So those trout in those rivers WILL have a major issue in their face within a very short period of time in evolutionary terms. Ice a mile thick kind of messes up your day as a fish. There will be a horrific disruption of the species found “in the wild” over all of Alaska, Canada, Northern USA and potentially even down into the southern states as they become cooler and wetter. When that happens, the minor color difference between cutthroat and rainbow will hardly matter, as something else will be the survivor. Perhaps one of them, or their hybrid, or some other fish entirely.
In some of the lakes of the Pacific Northwest (such as Crater Lake) there are salmon. I’m talking full sized migrate to the ocean salmon. Except they can’t migrate. They got trapped in some event (stocked in the case of Crater Lake), and had to deal with a ‘fresh water only’ life cycle. In the Amazon there is a freshwater dolphin. (The air breathing mammal kind). The Amazon at one time drained into the Pacific. Mountain uplift cut off that river and a giant lake formed. Then, long after those dolphin evolved into the fresh water dolphin, the Amazon River cut down to the Atlantic. Now we have a new species that doesn’t bother going back to the ocean. Think anyone can stop those kinds of changes? It is madness to think we are in control. At best, for single events like introducing an alien species, we can cause an unpredictable shift; but that is hardly control.
Back on that fishing trip in the ’60s, my Dad was thrilled to catch a cutthroat (it was about a foot long ;-) and said then that the rainbow was pushing them out. Yet the introduction of the rainbow trout was widely touted as “improving the sport fishery”. Since then, my avid fisherman brother-in-law has caught dozens of rainbow trout each year. I can’t say the program failed to achieve the objective.
Now you can argue over the merit of that program, but trying to rebrand it as “global warming” is just a flat out lie.
IMHO, Scientific (sic) American stopped having much to do with Science when it was bought by the Germans some years back. As of now, it is largely just a propaganda rag looking to fan social angst; near as I can tell. Yet even at that, this particular story is just so blatantly wrong and stupid on the face of it, even incorporating as evidence for their story the very proof that it is not related to warming (that clearly wasn’t happening in the ’40s and ’70s – as evidenced by the New Little Ice Age scare then, and the various temperature data sets).
The stupid, it burns…