Los Angeles - The coyote was limping as it approached a girl in a sand box at a public park - but it was still dangerous. It snapped its jaws on the girl's buttocks and her nanny had to pry the toddler from the wild animal.

Less than a week later, a coyote in a mountain resort town some 35 miles away grabbed a girl by the head and tried to drag her from a front yard until her mother scared it away.

A spate of coyote attacks in the fast-growing suburbs east of Los Angeles have left parents on edge and puzzled wildlife officials.

"Their aggressive behavior seems to be on the upswing," said Steve Martarano, a spokesman with the state Department of Fish and Game. "They just seem to lose their fear of humans."

Coyotes normally avoid contact with humans and hunt rabbits and rodents. But scientists said some that live near suburban developments are becoming bolder, raiding garbage or even attacking pets and humans.

An increase in coyote attacks on humans in the past decade is most evident in Southern California, where bedroom communities have quickly pressed into wilderness, allowing the canine scavengers to roam backyards for food.

Since the 1970s, more than 100 coyote attacks on humans in Southern California have been recorded, with half the incidents involving children age 10 and younger.

"If they see a young child and they have a chance, yeah they'll take it," said Kevin Brennan, a state wildlife biologist.

The only known fatality involved a 3-year-old girl in the foothill city of Glendale. She was fatally mauled in 1981.

"We're not sure what pushes them over the edge," said Robert Timm, a wildlife specialist with the University of California system. "There may be no single explanation for it."

One possibility is that coyotes give birth to pups this time of year and may need more food for themselves and their babies. Toddlers fall into the size of prey that coyotes would normally attack.

Another theory is that homeowners are unintentionally luring the wild animals by leaving pet food bowls outside or not securing garbage bins.

[It's also possible the coyotes are interbreeding with domestic dogs to produce coydogs, hybrids that according to Western lore have both the dog's lack of fear of humans and the coyote's aggressiveness.]

Game wardens don't normally hunt coyotes unless they pose a threat to people. After attacks, they trap and then shoot coyotes. They also carry shotguns or small-caliber rifles, but won't fire on the animals unless they get a clear shot.

Authorities dissuade people from hunting renegade coyotes themselves and suggest that they instead make noise or throw objects to scare them from neighborhoods.

Wardens have spotted the coyote that tried to drag a 2-year-old girl from her front yard Tuesday in Lake Arrowhead, about 65 miles east of Los Angeles, but did not have a clear shot to fire. They have since set up traps for it.

Authorities were also investigating reports of two possible attacks earlier this year in the same resort town in which a coyote may have bitten two young children in the buttocks as their father barbecued on the deck.

In the latest case, police said her mother was photographing the toddler and her siblings in front of the house when she ran inside to put the camera down. That's when a coyote tried to make off with the toddler.

The girl was treated for wounds to the head and neck, but was expected to survive.

Dotti Edwards, a neighbor, came home after the attack and spotted a scrawny coyote in the street. Her neighbors have complained of coyotes in recent weeks with reports of the wild animals sleeping in yards and pestering residents.

"They're so brazen right now," she said. "They just stand there and look at you."

Earlier, a coyote attacked a 2-year-old girl playing in a city park in Chino Hills, a suburb 30 miles east of Los Angeles that is connected to a state park.

The next day, a coyote in the same place made a beeline for another child, but the father scared it away.

Since last year, there have been seven coyote attacks in the Chino Hills area, including four in which children were bitten. State wildlife officials have killed 23 coyotes to protect the public.

Timm, the University of California scientist, said coyotes behave in predictable ways when they turn aggressive such as snatching pets during the daytime or chasing joggers and bicyclists.

If people recognize these signs, they may be able to thwart an attack, he said.

Timm has created a Web site, CoyoteBytes.org, where residents in Los Angeles, Orange and San Diego counties can report coyote bites or sightings. Scientists use the information to study the scope of the problem.

"Coyotes are opportunistic," Timm said. "They go where the food is."