SAN LEON — If you give a dog a toy, it may growl when you take it away.

At the Bay Area Society for the Prevention of Cruelty to Animals, that’s enough to end its life, according to former employees.

Former workers and volunteers at the society’s San Leon shelter say that since last year, perhaps hundreds of dogs and cats have been euthanized because they failed to pass the new shelter manager’s temperament tests.

Jennifer Rowan, the shelter manager, said she’s never claimed the shelter didn’t kill animals. She wouldn’t say how many animals the shelter has euthanized since it began temperament testing.

“We’ve never represented ourselves as a no-kill shelter,” she said. “We’re really working to educate the public that it’s a misleading term.”

In an interview with The Daily News last month, Rowan said the shelter accepts only animals that pass the temperament tests and doesn’t euthanize for space, as many area shelters do.

She said then the shelter euthanized animals if they were too sick or injured to be adopted but didn’t mention animals who fail what she conceded are “controversial” temperament tests would be put to sleep also.

Dr. Pamela Reid, the vice president of the American Society for the Prevention of Cruelty to Animals’ behavior center, said science supporting temperament testing is in its infancy.

“We don’t have a really good scientifically validated tool to offer shelters to use,” she said. “Science just hasn’t caught up with the need yet.”

An animal’s temperament is tested first by seeing if it walks toward people or away from them, Rowan said.

Then the tester puts a hand on the animal’s mouth and lifts up the lips to see how it reacts.

“I had a dog that tried to bite me,” Rowan said. “That’s not the kind of dog we need on the adoption floor.”

Testers also give animals toys and use an artificial hand to touch the animal and see its reaction. The artificial hand is also used to pet dogs to see whether they wag their tail. The hand is put in a bowl of food while the animal is eating to see whether it reacts to its food being disturbed, Rowan said.

The tester also claps to see how the animal reacts to loud noises.

“It’s very black and white,” Rowan said. “We go ahead and make recommendations based on what we’ve seen. It’s more of an adoptability assessment. It helps us market the animals.”

James Bias, the president of the society’s branch in Dallas, said officials there use temperament tests, also.

“It’s a gut check at best,” he said. “It will say if this dog or this cat is friendly or not friendly. It’s not just pass or fail. It’s about ranking the animal to see what’s going to be the best match. If it has midrange of food aggression, for example, we’d prefer it in a house without small children.”

Reid said shelters are often forced to decide between animals, and the tests can help. But they’re not everything, she said.

“Almost every behaviorist and trainer I know has a dog that wouldn’t pass that test, either,” she said.

Donna Reed, who was the shelter manager before Rowan, said she volunteered at the shelter after Rowan took over. She said even after the shelter began euthanizing animals who failed the temperament test, it marketed itself as a sanctuary where animals wouldn’t be killed.

“A dog any day of the week could test differently,” she said. “They get a lot of support because people do think they are a no-kill shelter. The only animals you’ll find are those you’d find in a pet store. There’s no place for animals to go that are unwanted or unloved for some reason.”

Former shelter employee Deborah Dean said she quit after seeing animals euthanized inexplicably.

“When I first started working there, it was a no-kill shelter,” she said. “We only euthanized if they were severely ill or if they were vicious. I’ve seen her euthanize a dog because she didn’t like it. If there’s a dog she doesn’t like, she tests it until it fails.”

Rowan said she does retest animals after they’ve been admitted. Some animals, especially dogs, get stressed in the shelter environment and become hostile, she said.

Former volunteer Charlotte Gioannetti was at the shelter before Rowan got there and for a few months under her leadership. She said the mission of the shelter changed dramatically from being a safe place for homeless animals to somewhere only aimed at getting more animals adopted.

“Many of them (killed) were healthy, sweet and would have transitioned well to a family,” Gioannetti said. “She didn’t even give them a chance.”

Rowan said since she’s taken over, the shelter’s adoption numbers have doubled.

“I feel it’s because people come to the shelter completely confident that they’re going to get a great animal,” she said. “It’s been exciting to see the numbers go up and up and up. That just means we’re helping great animals find great homes.”