If your backyard is full of holes because your canine is patrolling the perimeter for mice, rats, rabbits, moles and voles, then you may want to explore Earthdog as a sport.

Earthdog trials, or competitions, are sanctioned events in which dogs dig out the simulated dens of critters and then corner them. The U.S. is second only to Germany in the number of Earthdog tests conducted each year. Usually limited to terriers and dachshunds, standardized Earthdog tests measure a dog's natural aptitude for engaging behaviors when exposed to vermin underground lair, burrows or tunnels.

"For generations, small terriers and dachshunds were bred as hunting dogs to track game above and below ground; to bark at their quarry in the den, and to bolt or draw it for the hunter," explains the American Kennel Club's introduction to Earthdog trials. "Now these wonderful little dogs are very suitable as family pets; however, they sometimes have to be trained not to bark at every little noise and not to dig in the yard or garden. Barking and digging are what they were bred for all those years, so now AKC has developed the three levels of Earthdog tests for these game little dogs."

Local clubs

In Minnesota, three clubs, the Minnesota Dachshund Club (http://mdcdachshund .tripod.com), the Greater Twin Cities Su-Mac Cairn Terrier Club (www.sumac-cairns.com), and the Greater Twin Cities Fox Terrier Club (gtcftc.homestead.com) are determined to keep Earthdog thriving in the state. Interest in starting a new all-breed Earthdog club has been bandied about and the Duluth Kennel Club is planning to expand Earthdog tests to the northern part of the state. Minnesota Dachshund club president Marlies Noll has been a dachshund fancier and participant in Earthdog events for 25 years. "The satisfaction of Earthdog tests and competing is the sheer beauty of seeing your dog do exactly what it was bred to do," Noll says. "Unlike a lot of other dog events, your dog has to do it on its own; there's no human intervention. It really is a thing of beauty to watch a dog hunt independently, being very courageous and true to the function it was bred to do over a hundred years ago. For dachshund owners especially, having a small dog that shows such courage and tenacity is really a pleasure."

Four levels of Earthdog testing

The initial AKC Earthdog test, called "Introduction to Quarry," requires the dog to follow a scent, enter a 10-foot tunnel containing one right-angle turn, then "work" (bark or otherwise engage) the quarry - usually a caged rat that cannot be reached. The tiered tests of titled Earthdogs - Junior, Senior, Master - become increasingly more difficult as the dog hones its instincts.

The toughest, Master Earthdog, begins with the dog hunting with a bracemate (another dog) for 100 to 300 yards. During the hunt, the dogs must react to handler commands to investigate any unscented or empty dens. Both dogs must then enter an active den that is 30 feet long with at least three right-angle turns. There are obstacles like PVC pipe across the den to simulate a root, and the tunnel narrows down to six inches for more than a foot. The Master dog has 90 seconds to get to its quarry, work the vermin for 90 seconds, then be removed from the den by the handler within 15 seconds.

To see if your dog has the courage to follow a scent into an underground tunnel and find the caged rat, give Earthdog training classes a try. You both just might love it.

La Donna Seely is a volunteer for A Rotta Love Plus, www.arottalove.org, an award winning rottweiler and pit bull rescue, adoption and education organization.