This story was updated at 5:52 p.m.

Conservationists this week urged the public to support their effort to grant the African lion endangered species protection.

The push by members of the Congressional Animal Protection Caucus, Born Free USA and other groups comes as the Fish and Wildlife Service is reviewing whether the species merits listing as threatened or endangered (Greenwire, Nov. 27, 2012). A 60-day public comment period closes Jan. 28.

An initial petition to list the species pointed to disease, human-lion conflict over livestock, trophy hunting and the use of animal parts in traditional medicine as reasons for the species' population decline. Lion parts are used as remedies for everything from broken bones to erectile dysfunction, according to Adam Roberts, executive vice president of Born Free USA, an animal advocacy group.

"The United States is the world's largest importer of lion trophies," Teresa Telecky, director of the wildlife department at Humane Society International, said this week at a congressional briefing hosted by Rep. Jim Moran (D-Va.), who chairs the Congressional Animal Protection Caucus.

Using data gathered on the tracking of lion parts when they cross international borders, Telecky estimated that the equivalent of at least 7,445 whole lions was traded internationally over the past 10 years.

The Endangered Species Act generally prohibits importation of the animal's parts into the country for either trophy or commercial purposes, Telecky said.

Decreased habitat also threatens African lions, experts said.

Only 25 percent of Africa's original savannas are currently able to sustain lion populations, according to a study last year from Duke University researchers.

"There is no way to consider the African lion as anything but endangered," Roberts said.

Not everyone agrees.

Hunting advocates cite the economic, land and animal-conservation benefits of sport hunting to African nations.

"Trophy hunting is of key importance to conservation in Africa by creating [financial] incentives to promote and retain wildlife as a land use over vast areas," according to a fact sheet from the Safari Club International, which opposes listing of the species.

But recently, Zambia and Botswana banned sport hunting of the African lion. Kenya instituted a similar ban more than a decade ago.

Bill Horn, director of federal affairs for the U.S. Sportsmen's Alliance, which provides lobbying support for hunters' rights, said the species could be better managed through sustained-use programs, rather than an endangered species listing.

"It's been our experience that good sustained use programs that generate revenues are really the best way to go," Horn said.

If FWS decides to list the species, Horn said, he hopes the listing would apply to lions only from certain parts of Africa. "There are differences across the continent," Horn said. "Focus on [areas] that are in trouble and don't penalize others with a blanket ESA."

Despite the arguments for and against granting the species protection under the Endangered Species Act, substantial steppingstones still stand in the way. For one, an ongoing debate persists over how many lions once lived in Africa.

There is a general consensus that 32,000 to 35,000 lions currently live in Africa, but estimates vary widely about how many once lived there. Those data are crucial to determine long-term trends. And researchers concede that no matter who conducts a study or what method is employed, estimating lion populations is an imperfect science and a challenging endeavor.

Horn said his group is working with scientists and experts to come up with their own lion population numbers. He said he didn't want to comment on the numbers before the study was completed, but "petitioners have skewed the numbers in a downward position."

The African lion remains the only big cat without endangered species protection, according to the International Fund for Animal Welfare. The Asiatic lion was listed in 1970.