Glacier National Park suspended a University of Montana mountain goat study last week after the first two animals that researchers attempted to capture died.

On Tuesday, June 8 in the Many Glacier Valley, a 6-year-old male mountain goat died after it was darted and tranquilized in the Ptarmigan Lake Trail area of Mount Altyn by Wildlife Conservation Society veterinarian Dr. Robert Moore. On Thursday, June 10, a second goat died after it was it shot with a tranquilizing dart.

Both goats were males. The second goat hadn't been recovered as of presstime. It was dead on a ledge that researchers couldn't safely get to.

The first goat went into respiratory arrest. Dr. Moore gave the goat an antidote for the tranquilizing drug as well as breathing support for 45 minutes, but the goat perished. It was later learned the goat died after the tranquilizing dart punctured its ribcage.

After the second death, Glacier halted the study, at least for the time being. The study hopes to track movements of goats in the Park, their habitat, responses to temperature changes as Glacier experiences global climate change and population demographics. The basic question, park officials note: Will Glacier become a refuge for goats?

But after the deaths, the tone has changed.

"We need to find out all we can about what went wrong and learn about the mistakes," said Joel Berger. "(And ask) Do the risks outweigh the benefits?"

Berger is the John J. Craighead Chair and professor of Wildlife Conservation at the U of M Division of Biological Sciences. He is overseeing the study, done by doctoral candidate Stefan Ekernas.

Researchers planned to dart 30 mountain goats over the next two summers with a goal of collaring 15 this year and 15 next year. The idea was to fit them with radio collars as well as temperature monitors under their skin, to see how they react to warming temperatures in Glacier.

The study was planned to continue through 2013.

Berger has caught and tracked dozens of different creatures through his career, most recently a musk oxen study in Alaska where 90 animals were caught and collared without a fatality.

But Glacier's goats present special challenges. The Park is a very public place and the goats are endearing. But they live in difficult terrain where a captured animal could fall off a cliff or die from stress. There are other methods used to capture goats, such as using helicopters with net guns. The goats are captured in nets, their eyes are covered, they're collared and released. Once their eyes are covered, the animals calm down. Bighorn sheep have been captured in this manner by Montana Fish Wildlife and Parks on several different occasions. Goats can also be caught in box traps.

But there is still a fundamental question.

"Is it necessary to handle goats?" Berger said. "It's a debate worth having."

That discussion will likely go on for several weeks, Berger noted. The second goat, as off presstime hadn't been recovered, and a full necropsy will be performed on the recovered male.

"We haven't closed the door on the study," Park spokeswoman Amy Vanderbilt said.

She did note the Park prefers non-invasive means of study, if possible.

Animal fatalities from tranquilizing operations have occurred in the past. A bighorn sheep study in Glacier where sheep were darted and collared also had some fatalities and last year a grizzly bear cub died from a tranquilizing dart as well.

Glacier is currently doing a non-invasive count of goats in the park. A citizen science study headed by UM researcher Jamie Belt involves trained volunteers who go into the field and count goats.

That study should give the Park a baseline population estimate of goats, but doesn't speak to their movements.