LANDER -- A lawsuit asking a federal judge to immediately reinstate Endangered Species Act protection for gray wolves offers only "speculative worst case scenarios" and provides no compelling evidence to justify such an "extraordinary" demand, the state of Wyoming argued Friday.

The Cowboy State intervened as a defendant in the lawsuit against the wolf delisting decision. Conservation groups are seeking to get wolves immediately put back on the endangered species list while the larger case against delisting is pending.

Wyoming, as anticipated, has now officially challenged that request, and the states of Montana and Idaho were expected to do the same.

Last week U.S. District Judge Donald Molloy denied a petition by the federal government to delay a hearing of the injunction request, saying he's "unwilling to risk more deaths." Molloy has set the injunction hearing for May 29 in Missoula, Mont.

In documents filed Friday, Wyoming argues that the request to relist wolves is based on unproven beliefs and conjecture, rather than sound science, in an "attempt to convince this Court that the wolf population (in the Northern Rockies) might be in peril at some unspecified time in the future."

The state, represented by Deputy Attorney General Jay Jerde, argued: "Nothing could be further from the truth."

At least 40 wolves have been killed in Wyoming, Idaho and Montana since the canines lost federal protection in March. According to Wyoming's court documents filed Friday, 19 wolves have been killed in that state since delisting, although the Star-Tribune has only been able to confirm 17 so far. State officials weren't available late Friday to clear up the discrepancy.

Despite all of the wolf killings since delisting, Wyoming asserted that is was an "irrefutable truth" that "a moderate amount of human-caused mortality in any given year will not cause a decrease in the wolf population in Wyoming or the (Northern Rockies)."

The state is basing its argument, in part, on the following numbers:

* In 2007, the U.S. Fish and Wildlife Service killed 63 wolves in response to livestock depredations, yet the population still increased from 311 to 359 wolves that year.

* Over the past 14 years, on average, 23 percent of the total population of wolves in the Northern Rockies has died annually, yet the wolf population has increased by 24 percent per year over that same period.

In Friday's filing, Wyoming also challenged the assertion made in the injunction request that the U.S. Fish and Wildlife Service failed to consider "the best science available" when it decided to delist wolves. The injunction request argues that the most recent genetic studies indicate that at least 2,000 to 3,000 wolves in genetically interconnected populations would be required in order to protect against inbreeding in the long term.

The Fish and Wildlife Service did, in fact, consider the main scientific study cited by the conservation organizations, the state argued Friday, and the lawsuit is merely offering "a conflicting interpretation of the study."

Franz Camenzind, biologist and head of the Jackson Hole Conservation Alliance -- one of the organizations challenging the delisting decision -- said the state's action was nothing that wasn't anticipated by all parties involved.

"We have to remember that this (lawsuit) isn't just targeting Wyoming. We're just as concerned about what's happening in Idaho," Camenzind said. "At the end of the day, this will be decided in the courts, not in the press."

As for the state's claims that the population is in no danger of declining, Camenzind said there are no assurances built into the Cowboy State's wolf management plan that there won't be a drastic fall-off in the coming years.

And he also argued that the scientific claims made by the conservation groups should not be dismissed as the state suggests.

"In the long term, we do believe the peer-reviewed genetic studies make a clear case for having as many or more wolves than we have now," he said. "And not only more animals, but genetic connectivity between them, which up until now there is no evidence of it having occurred."

Environment reporter Chris Merrill can be reached at chris.merrill@trib.com or at (307) 267-6722.