Turf wars: Goats clash with sheep as key U.S. glaciers melt

This story was originally published by The Guardian and appears here as part of the Climate Desk collaboration.

In one corner, there is the agile climber with steak knife-like horns. In the other is America’s largest wild sheep. They are locked in significantly one-sided combat in the mountains of the U.S. west, scientists have found, in a battle over resources uncovered by the region’s vanishing glaciers.

In study sites across a 1,500-mile span of the Rocky Mountains, scientists have documented mountain goats and bighorn sheep competing over mineral deposits among the rocks, at elevations of up to 14,000 feet.

These contests, never previously outlined in detail, show that two of the U.S.’s heftiest native mammals are involved in a struggle that may be influenced by the climate crisis, as the mountains’ snow and ice rapidly dwindles. Conflict between such species “may be reflective of climate degradation coupled with the changing nature of coveted resources,” the new study states.

Joel Berger, lead author of the research and senior scientist at the Wildlife Conservation Society and Colorado State University, said he was “flabbergasted” to see the number of skirmishes between the two ungulate species, with the mountain goats appearing to have the upper hand, or hoof. Of the observed battles, the goats triumphed 98 per cent of the time, clearly making them the superior mountain brawler.

“They are the badasses of the mountains,” said Berger. “They have these sabre-like horns; they are bolder, more aggressive. The goats just have a very high win rate.”

The goats and the sheep usually avoid battle when near each other but when conflict does arise around clumps of minerals, the goats typically chase off the sheep in order to enjoy the nutrients in peace.

Bighorn sheep are roughly the same size as the mountain goats and sport long, curved horns that resemble a Princess Leia hairstyle. But the goats are the more feared combatant due to their assertiveness and razor-sharp horns — a mountain goat gored a grizzly bear to death in Canada last year, while in a separate and extremely rare incident, a hiker was killed by a goat in Olympic National Park in 2010.

About 300 glaciers have disappeared from the Rocky Mountains over the past century as global heating has winnowed away the region’s snow and ice. Scientists have said it is now “inevitable” that places such as the celebrated Glacier National Park will lose all of their major ice formations within the coming decades.

This upheaval is disrupting ecosystems and raising concerns for communities in the U.S. west that rely upon water that comes from rivers and streams fed by melting glaciers. The melt is also uncovering deposits of salt and potassium that are valued by the goats and sheep, who need to lick these mineral deposits in order to gain crucial nutrients.

These animals, able to move deftly up rocky inclines, are now able to venture higher into the mountains for these resources as the ice retreats. This may be leading to more of these irate interactions, although it’s not clear whether the conflicts are increasing in number as no previous work has been done on the topic.

“Not long ago, these areas were covered in ice and snow. They’ve now opened up and there’s some conflict over access,” said Berger. “Direct conflict isn’t something any of these species want, but this is what happening.”

Berger said that global heating was heightening the risk of conflict in various parts of the world, among creatures such as rhinoceroses and elephants as they try to access diminishing water supplies. Some humans, too, are reacting to these changes with adversity in mind, with the U.S. and Russia viewing the melting away of the Arctic as a military threat.

“Whether we are dealing with humans or non-human mammals, we know climate change is reshaping all of our futures,” Berger said.