It isn't the presence of jaguars and crocodiles but the invasion of drug traffickers and slash-and-burn squatters that rangers fear.

"They see us as the enemy," said Edin Orlando Lopez Tejada, the technical director of the Guatemala National Park Service's branch in the northern Peten region. "Our people only patrol with the army and the police."

The 1,120-square-mile Laguna del Tigre park now is a refuge more for outlaws than for wildlife. Here, Guatemalan migrants in league with Mexican drug traffickers have carved out ranches with jungle airstrips.

"It's much more 'wild' outside the park than inside," Lopez Tejada said.

In theory, some of Guatemala's strictest laws protect Laguna del Tigre. In fact, the park, which abuts the Mexican state of Tabasco, serves as a corridor for cocaine smugglers.

The human population in the park has doubled to about 35,000 scattered around some three dozen hamlets, Lopez Tejada said.

The park service has had more luck turning back invaders who are outside the park but still within the surrounding Maya Biosphere Reserve, also a protected area.

"This year alone, 109,000 hectares [420 square miles] of the Maya biosphere were recuperated from the hands of well-armed and organized gangs," Roan Balas McNab, the Guatemala country director for the Wildlife Conservation Society, said in an e-mail. In some cases, drug gangs were "using needy communities that recently arrived to the reserve as cover, and as cheap labor."

Recovering protected lands is an uphill battle.

And drug gangs, such as the well-armed Zetas from Mexico, are even harder to challenge.

"It is no secret that these people are much better armed than our security forces. This is the reality," Lopez Tejada said.