(CNN) -- The Humane Society of the United States said Wednesday it does not fault authorities in Ohio for using lethal force against exotic animals running loose.
Police believe the animals' owner, Terry Thompson, 62, freed the animals -- lions, tigers, leopards and grizzly bears -- at his preserve near Zanesville, Ohio, before dying from a self-inflicted gunshot wound, Muskingum County Sheriff Matt Lutz said.
Ohio authorities were called to the scene Tuesday night. As of Wednesday, 49 animals had been killed and the rest were accounted for except for one monkey, according to authorities. But Lutz and conservationist Jack Hanna, who assisted in the effort, said the animal may have been eaten by one of the big cats.
A preliminary investigation showed Thompson had pried open cages and left fences open, Lutz said. Autopsy results on Thompson were pending.
Authorities were trying to use tranquilizers whenever possible in capturing the animals, said Zanesville Mayor Howard Zwelling. But Lutz said some animals were shot at close range by deputies who found themselves in a dangerous situation. A Bengal tiger was put down after it became agitated following a tranquilizer shot.
While the killing of animals might prompt initial concern, "we do not fault them for using lethal force," said Debbie Leahy, captive wildlife regulatory specialist for the Humane Society of the United States.
"What we're finding, in places where they have lax regulations ... rural sheriffs and local animal control officers are being forced to deal with issues ranging from rampaging chimpanzees to tigers running amok," Leahy said. Such officers are not trained to deal with such situations and may lack the proper equipment, she said.
Zwelling said he had received calls from people concerned the animals were killed. But, Lutz said, "we are not talking about your normal everyday house cat or dog. These are 300-pound Bengal tigers that we have had to put down. When we got here, obviously, public safety was my number-one concern. We could not have animals running loose in this county."
While tranquilizers are an option, there are issues involved in their use, Leahy said. For one thing, they take time to work on an animal, potentially giving it time to harm someone or to get away. In addition, if an animal has a high level of adrenaline, tranquilizers can make them more agitated, she said.
"People shouldn't be blaming (authorities)," she said. "They should be blaming the Ohio government for not taking action to prevent this incident."
The Humane Society urged Ohio officials Wednesday to issue an emergency rule to crack down on exotic animal ownership. A previous emergency order issued by then-Gov. Ted Strickland that prohibited people convicted of animal cruelty from owning exotic animals expired in April. The organization said Thompson "would almost certainly have had his animals removed by May 1, 2011, if the emergency order had not expired."
"Every month brings a new, bizarre, almost surreal incident involving privately held dangerous wild animals," said Wayne Pacelle, president and CEO of the Humane Society, in a prepared statement. "In recent years, Ohioans have died and suffered injuries because the state hasn't stopped private citizens from keeping dangerous wild animals as pets or as roadside attractions. Owners of large, exotic animals are a menace to society, and it's time for the delaying on the rulemaking to end."
People for the Ethical Treatment of Animals also said the lack of an exotic animal ban is to blame.
"The shooting of dozens of exotic animals in Zanesville is a tragic example of just how wrong things can go when people are allowed to keep wild animals," PETA said in a written statement. The organization said it hoped the incident will be a "wake-up" call to current Ohio Gov. John Kasich, who, according to PETA, refused to extend the emergency ban on exotic animals.
"Keeping exotic animals is inhumane and unsafe for both animals and people, and it's time that Ohio did something about it," PETA said.
"People have to understand something ... human life comes first," Jack Hanna, director emeritus of the Columbus Zoo, told CNN. He said some had asked why the animals weren't tranquilized by authorities searching for them Tuesday night, but "you can't tranquilize an animal in the dark. It upsets them ... they settle in, they hunker down, they go to sleep. Obviously, we can't find them in the dark. So what had to be done had to be done. Even a bear came after one of the officers last night, and she was just trying to get out of a car. ... No one loves animals more than me, but human life has to come first."
When first responders do have to shoot an animal, "we have found, in some cases, they're just as traumatized as the rest of us," Leahy said, and sometime require counseling. "They don't want to have to shoot these animals."
She recalled a case a few years ago involving a Florida police officer who shot an elephant running wild with children on its back.
"He was so totally upset by that incident that he became a huge elephant advocate," speaking out for stronger laws on their behalf, Leahy said.