Our resident expert answers your burning questions in his weekly "Ask a Bear" column.
Q. Dear Bear,
What’s the latest on pizzlies? Are their population numbers increasing in a noticeable way, or are they still considered pretty rare?
— Trent K., Boulder
A. Dear Trent,
While the term “pizzly” is an acknowledged and acceptable term for a hybrid between a polar bear and a grizzly, I must note my preference for the portmanteau “grolar.” Pizzly sounds light, fizzy, a little goofy; it’s a mere two letters away from bathroom humor. Grolar is just so phonetically regal, tough, and mean — as befits the exceedingly-rare-but-no-doubt-fearsome result when the two reigning terrestrial champs of the order Carnivora drop their guard and put on a little Marvin Gaye.
About that exceedingly rare: We’re talking crazy rare, with only three confirmed cases ever found in the wild. (The last confirmed sighting happened when a hunter in Canada shot one in 2010.) And while brown bears and polar bears are genetically quite similar — both species evolved from the same ancestor only 150,000 years ago -- opportunities to mate don’t crop up every day. For one, while their ranges overlap somewhat above the Arctic Circle, preferred habitat is very different and maps to their respective ecological niches: Polar bears like to mate out on the sea ice, while brown bears do-the-do on land. Additionally, super-powerful carnivores instinctively realize that another predator of equal size presents an opportunity for unnecessary scuffling, and the species tend to avoid each other. (More aggressive brown bears sometimes chase off polar bears from whale carcasses.)
Most scientists theorize that there have always been grolars since the species diverged, in places where barren-land grizzlies share habitat with polar bears, but that it was never frequent. Some scientists speculate that with the onset of climate change, we could be seeing more grolar bears in the wild as polar bears are driven inland to formerly grizz-only habitat. But there isn’t a lot of hard data to support any of this. The most recent sighting in 2010 has some researchers questioning the parentage of some ultra-blond grizzlies they’ve seen above the Arctic Circle, but without significant DNA surveying, there’s no way to be sure. Additionally, known grolar bears in zoos tend to skew polar: They look slightly more like polar bears, play in the same way (by tossing bags like a seal) and even lie down the same way, with legs splayed out behind them.
In the plus column, polar bears do seem to be adapting to hunt on land more often in some areas like the Hudson Bay region, where scientists have observed them relying on snow geese, eggs, and caribou for food. Other scientists argue that male grizzlies are for the most part responsible for hybridization, and they’ve been observed going out onto the sea ice in search of food and maybe even mates. Additionally, residents of Ulukhatok, Northwest Territories – near the site of the last confirmed hybrid – say they’ve seen grizzlies (which are nonnative to the area) following altered caribou patterns into the region, overlapping with polar bear territory, and potentially mating with polar bears.
Another wrinkle: Some scientists speculate that pizzlies might not even be primed for ecological success. Their tendency towards polar-bear traits means they’d be less successful than grizzlies in land-based foraging, but their slightly darker or even mottled color will make them more noticeable to prey on sea ice. Hybrids just can’t get a break, it seems. So what’s the final word? This bear is going to go with “nobody really knows.” It’s possible that grolar bears populations are increasing, but even if it’s true, it’s likely at an imperceptible rate. Which means that for now, the mysterious pizzly/grolar bear remains as rare as the Yeti – and in some cases, it IS a yeti. —Bear