Jaguars, which once roamed much of the southern U.S. but are now endangered—if not extinct—here, were slated to get a new so-called critical habitat to encourage their repatriation.

But the big cats might have to wait south of the border a little bit longer. The U.S. Fish and Wildlife Service (FWS), which is responsible for establishing habitats for endangered animals, had promised to announce a designated area for jaguars (Panthera onca) by January 2011—after being sued by the nonprofit groups Center for Biological Diversity (CBD) and Defenders of Wildlife. In an October letter to the two nonprofits, however, the agency wrote that it would need another year for analysis of the species and habitat before making its decision.

Michael Robinson of the CBD calls it "an unfortunate delay that the jaguar can ill afford." The area proposed by the conservation group, which includes parts of Arizona and New Mexico, is being developed, he notes, rapidly closing off potential jaguar corridors. A "critical habitat" designation, which is what the group is seeking for the big cats, would not halt development, rather it would mean denying any federal-level permits for landscape alteration—say, draining a wetland or filling in a riparian area—that would make the area less advantageous for the cats.

The area the group has in mind, though, is no small plot of land. The CBD is recommending some 21.5 million hectares across two states. And that, says FWS Arizona Ecological Services Office field supervisor Steve Spangle, is "larger than any other critical habitat that I'm aware of."

Robinson contends that the size is not based on how many jaguars might currently be in the area but on how many there could be in the future.

The controversy over the agency's management of the species came to a head last February, when an Arizona Game and Fish Department trap that was meant for black bears and cougars snared and killed "Macho B," the last known U.S. resident jaguar. Despite occasional sighting reports, no jaguars have been formally captured on film.

Others who have worked with jaguar conservation are not convinced that the critical habitat is necessary, pointing to the apparent dearth of jaguars in the U.S. as a sign that the prospective area is not its preferred home. Alan Rabinowitz, president and CEO of Panthera (a nonprofit big cat conservation group), called the plan "nothing less than a slap in the face to good science" in a January op-ed in The New York Times shortly after the FWS first announced its earlier plans to designate an area for the big cats. "The American Southwest is, at best, marginal habitat for the animals," he noted, adding that to really boost the species' chances, efforts should be focused on their current, more established habitats in Latin America, where his group works.

Both those for and against the project note that the outcome of the jaguar habitat could have implications for future interpretation of the U.S. Endangered Species Act, which currently requires the FWS to establish critical habitat areas for species on the list. A later amendment to the law, however, noted that the agency can weigh potential negative economic impact of habitat designation in deciding whether to create a new habitat area.

The FWS is putting together a Jaguar Recovery Team with experts from the U.S. and Mexico to further study the potential jaguar populations as well as their potential habitat. "We believe it's better to do it right than do it fast," Spangle says.