Eight desert bighorn sheep skulls go on the auction block this week to raise money for preserving the once-endangered animals.

The skulls with spectacular horns have been found around Southern New Mexico, often in national forests or on Bureau of Land Management land in the "bootheel" area.

But because the animals have been protected in New Mexico for more than 30 years, the skulls have been kept by the state Department of Game and Fish.

Desert bighorn sheep were classified as endangered in New Mexico in 1980, when only 70 of the animals remained in the wild in the state.

In 2008, as their numbers increased, they were downlisted to a threatened species.

Last November, when the number of desert bighorn sheep reached 645 in seven herds around Southern New Mexico, the State Game Commission took them off the threatened-species list, allowing the skulls to be sold.

Another subspecies, Rocky Mountain bighorn sheep, found in Northern New Mexico, have never been listed as threatened or endangered in New Mexico. But the total populations of all bighorn sheep have plummeted over the last century.

People interested in the desert bighorn sheep skulls -- six from rams and two from ewes -- may see them and make written bids Wednesday and Thursday at the department office at 1 Wildlife Way off Caja del Rio Road next to the Marty Sanchez Links de Santa Fe golf course.

Friday through Sunday, they will be at the Bob Gerding's Hunting & Fishing Show at the Manuel Lujan Building at Expo New Mexico, the state fairgrounds in Albuquerque. Admission to the show is $8 for adults and free for children 11 and younger.

The bidding for the first four skulls will close at 4:30 p.m. Saturday. Bidding for the remaining eight will close 3:30 p.m. Sunday. Winning bidders will be able to pick up their skulls and pay for them Feb. 13-17 at the department offices in Santa Fe or Albuquerque.

Department spokesman Dan Williams said that during a special auction of desert bighorn sheep skulls in 2005, one large skull went for $31,000. This time, as in 2005, the money raised from the auction will go to a restoration program for the animals, he said.