Beavers get tough defending their turf

"They were harassed for years. And they finally said, 'that's it,'" said Coltrane, the Anchorage area wildlife expert.

These days the beavers go on the offensive, chasing pooches out of the lake even when unprovoked.

After beavers sent at least half a dozen dogs to veterinarians for stitches or worse this spring, the city Parks Department this week posted signs at the popular off-leash dog park. "WARNING AGGRESSIVE BEAVERS ARE LIVING IN UNIVERSITY LAKE!" the notices read.

The lakeside battles served as a seemingly annual reminder: Living in Anchorage means sharing the city with a menagerie of animals, including these industrious, sometimes ornery rodents.

While many people admire them, the animals are often in conflict with city life and you might be surprised how many places they pop up around town.

University Lake is the only place beavers have been reported to regularly attack dogs.

But they chewed down trees freshly planted for a road and trail improvement project on Romig Hill near Westchester Lagoon.

They've gnawed vegetation up and down Campbell Creek.

Their construction projects have raised the water level and contributed to basement flooding near Windsong Park east of Muldoon Road.

The topic of beavers came up randomly at a meeting at the school district earlier this month.

Noting downed trees along Dimond Boulevard, School Board member Don Smith turned to a city parks official. "Isn't there some way we can trap some of these beavers and send them all to a nice lake," he asked.

The answer, Coltrane says, is no.

IN PARKS, BEAVERS REIGN

Most of the city's good beaver habitat is already home to beavers, the biologist said. They are territorial animals and likely would chase any newcomers away.

Self-taught Anchorage beaver expert Cherie Northon, a former University of Alaska Anchorage professor, puts it another way: "They will probably get the crap beat out of them."

In Anchorage, the Fish and Game Department generally leaves beavers alone unless they cause flooding in somebody's yard or basement, or they're dropping trees along power lines or on cars and houses, Coltrane said.

"We don't just remove beavers if they're taking down trees in a park," she said.

Or even if they're biting dogs in a park.

By remove, she means kill.

WHEN BEAVERS DIE

Killing beavers is so controversial that when Fish and Game thinks it has to be done, they usually do it clandestinely, at night, said Coltrane.

If a beaver colony has become too much of a problem, sometimes the animals are shot. Sometimes they're killed in traps.

David Doering, a homeowner on Reflection Lake east of Boniface Parkway near Tudor Road, is fine with that.

"Beavers are great fun to watch, but in a residential area it doesn't quite work out."

The lake is small at 7 1/2 acres, said Doering, and surrounded by homes. A creek runs out of the lake next to Doering's house.

Several years ago, beavers dammed an area next to his property, flooding some of the land. They also chewed down trees behind other people's houses. Eventually former Fish and Game biologist Rick Sinnott and some trappers came out and shot four beavers. They trapped another four, Doering said.

When another pair of beavers showed up this spring and began building dams, Doering called Fish and Game.

Some trappers have already visited, he said.

'INCREDIBLE ENGINEERS'

Northon, the former UAA professor, said she understands some beavers have to go.

"I just think they're the coolest creature out there. I hate it when they overstep the boundary and have to be taken out."

Northon is a geographer by training, but married a biologist and over years of study picked up information about beavers. She is now executive director of the Anchorage Waterways Council.

Here's some of what she knows about the creatures, the largest rodents in North America:

Beavers have flat tails that they smack as a warning mechanism. They have tiny front arms, but in the water, the animals are powerful, and can drag trees 30 to 40 to 50 feet.

"Their teeth grow continuously which is one of the reasons they keep taking trees down," Northon said.

They build lodges for protection. The lodge is where they live, give birth, and raise their young. The entrances are usually under water, and the animals can hold their breath for 15 minutes.

"They are incredible engineers. They cut their logs almost like they had a tape measure."

Northon has seen a lodge that incorporated flat rocks in mud, all the same size and shape. They mate for life, giving birth around March, she said.

In the fall, the beavers take down young saplings and cache them for winter under water. When the top of a waterway freezes over, you can see a pile of branches under the ice, where the water's not frozen.

"That's their food," Northon said.

DOGS BEWARE

Fall is usually when beavers are most active, and is the peak time for damage such as flooding, said Coltrane.

But people should know that University Lake beavers are actively attacking dogs right now, said Dr. Ginny Kunch, a veterinarian at the 24-hour Diamond Animal Hospital & Emergency Services, which is on Tudor Road near the park.

Kunch recommended posting warning signs at the lake after a beaver bit a wading Weimaraner in three places during the first week of June.

The dog was under anesthesia for two hours while she repaired severe muscle and tissue damage, Kunch said.

It was the fifth or sixth beaver-bitten dog to come into the clinic so far this year, she said.

Stacy Smith's 11-year-old pitbull Willoughby was bitten the first week of June, too, and went to a vet in Eagle River.

Smith said she'd been going to University Lake for years and never saw a beaver until a couple of days before the attack, when she saw one on land. "It was slamming its tail and angry," she said.

On June 2, Willoughby was swimming when Smith saw the beaver heading for him, and called him out. He wasn't quite fast enough, and got bitten in the thigh.

He's doing fine now, said Smith.

But last fall, a German shepherd mix died during surgery for a beaver bite, Kunch said. The cut didn't look fatal, she said, but the dog had been agitated, cold and wet. "It's hard to know what happened," Kunch said.

Even though her dog was injured, Smith said she doesn't feel the beavers should be taken out. "The lake is their home and they deserve to be there," she said.

Reach Rosemary Shinohara at rshinohara@adn.com or 257-4340.