Pomeo & Gruliet

Amid ever-shrinking habitats and ecosystems, biologists are grappling with how to protect species in a changing climate.

Two species, both alike in dignity In warming Arctic, where we lay our scene 
From dwindling ice to heated land
Where carbon theft makes habitat unclean
A pair of star-crossed lovers test their life
And misadventures come perilous to each
Do make a child …

A glooming peace in morning?
Uncertain future at noon?
Go hence and talk of warming days,
And the union of two sad bears in a climate of woe
For there never was a tale as this –
Of Gruliet and her Pomeo. 

Two species, both alike in dignity In warming Arctic, where we lay our scene 
From dwindling ice to heated land
Where carbon theft makes habitat unclean
A pair of star-crossed lovers test their life
And misadventures come perilous to each
Do make a child …

A glooming peace in morning?
Uncertain future at noon?
Go hence and talk of warming days,
And the union of two sad bears in a climate of woe
For there never was a tale as this –
Of Gruliet and her Pomeo. 

                                           – M Ruby with apologies to William Shakespeare

IT'S A FAMILIAR STORY: two star-crossed lovers battle distance, race and disapproving families to be together. Defying the odds, they are driven to produce the ultimate expression of love – a child. But this is no modern-day version of Shakespeare’s famous tragedy. Instead of teenagers rebelling against an ancient family feud, the paramours in this story overcame obstacles far more onerous than those faced by Shakespeare’s young romantics. These “lovers” came from the esteemed and noble houses of Grizzly and Polar.

Various kinds of bear hybrids have been produced in captivity since the 1870s. But the wild Arctic union between polar and grizzly bears first came to light in 2006, when Idahoan hunter Jim Martell shot what he and his Inuit guide thought was an Ursus maritimus on Banks Island, in the Northwest Territories. After the white bear had been killed, authorities noticed that it bore distinct grizzly-bear features, such as brown patches around its eyes and on its back, and a dished face.

The Northwest Territories Environment and Natural Resources Department confiscated the bear for further study. If it had been identified as a grizzly, Martell would have faced a $1000 fine and up to a year in jail for shooting an animal for which he did not have a hunting tag. However, genetic testing determined that the animal was half polar bear so the Environment and Natural Resources Department returned the dead animal to Martell, who had paid $50,000 to bag it.

Sadly, grizzly and polar bears getting hitched in the wild is more likely due to desperation than love. The two species have drastically different mating habits, and their pairing may signal that both are having difficulty finding mates. But instinct runs strong, strong enough at least to overcome the grizzly’s desire to mate on land versus the polar bear’s preference for an ice floe.

Biologists theorize that grizzly-bear ranges, which normally extend to the Arctic mainland, have been shifting further north in recent years, perhaps due to a warming climate. This could be a significant problem for polar bears, which are already losing territory due to shrinking polar regions.

“As grizzly bears expand their range north, [interbreeding] becomes another potential threat to polar bears,” says David Paetkau, a geneticist with Wildlife Genetics, the BC firm that determined the bear’s dual lineage. “If there is too much interbreeding, the grizzly bear genes could eventually overwhelm the polar bear, and they could become basically grizzly bears with a little more northern habitat.”

In addition to concerns about diluting the gene pool of rare bears, others are worried about whether a hybrid would be protected under existing endangered species legislation. According to the US Fish and Wildlife Service, hybrids between endangered and other species or subspecies are not extended the same protection as endangered purebreds. In Canada, the Species at Risk Act does not explicitly exempt hybrids from protection, but the fact that Jim Martell was not fined for hunting a half-grizzly indicates that any mixed-breed species would not be afforded the same protection as its purebred parent.

The issue is further complicated by the ongoing battle between various conservation groups, government agencies and lobbyists over the legal status of the polar bear in the United States. In 2008, the bears were listed as threatened under the Endangered Species Act, largely because of melting polar ice caused by climate change. However, a Bush Administration rule limited their protection by saying that no actions outside of the Arctic could be considered a threat to the bears. This rule has been the source of much contention. Environmental groups argue that human actions such as carbon emissions are the main cause of the diminishing habitat, while lobbyists for business interests argue that it is inappropriate to use the Endangered Species Act as a tool for addressing climate change.

North of the border, environmental groups have pushed for a “threatened” rating for Ursus maritimus. However, the polar bear remains a “species of special concern” under recommendations from the Committee on the Status of Endangered Wildlife in Canada, and the federal government has not made a final decision on the bear’s status. The decision is muddled by the fact that although certain bear populations are declining due to reasons as diverse as melting sea ice and over-hunting, other populations are stable or increasing.

The lack of legal protection for hybrids, combined with the legislative quagmire surrounding polar-bear protection in the United States and Canada, makes the polar-grizzly hybrid even more vulnerable than other species.

This brings up the question of whether authorities should try to limit the bear hybrids. In the southern United States, for example, conservationists have undertaken sterilization programs to prevent the breeding of red wolf-coyote hybrids, in order to stave off any dilution of the red wolf gene pool.

Government officials and other wildlife authorities have not yet decided whether to discourage unions such as the one between Pomeo and Gruliet, or to allow nature to take its course. If the hybrids become more common, populations of purebred polar bears could decline, making the species even more vulnerable to habitat loss caused by climate change. However, the hybrids could be better suited to the changing Arctic climate.

For now, wildlife biologists and researchers are waiting to see whether the two species will begin to mate with more frequency before making any decisions.

 

Meaghan King recently completed her master’s in Environment and Resource Studies at the University of Waterloo.