Various tests on the 155-pound male bear continued one day after he knocked Esther Schwimmer out of her stroller and carried her into nearby woods, as her mother shuttled her 4- and 2-year-old siblings inside.
The 3-year-old bear dropped the infant after witnesses began throwing rocks at it, but the baby died shortly afterward of severe head and neck injuries.
"Babies smell different. They have powders on them, milk on their clothes that may have been spilled," said Ward Stone, wildlife pathologist for the state Department of Environmental Conservation. "Maybe something was in the baby's diaper that smelled like milk."
Lou Berchielli, a DEC black bear specialist, speculated that the bear merely grabbed Esther because he was curious.
"We could come up with any individual quirky explanation that we want," said Lynn Rogers, director of both the Wildlife Research Institute and North American Bear Center in Ely, Minn. "It's possible, but unprovable."
The untagged bear tested negative for rabies, Stone said. He said he will continue to test for other illness, such as West Nile virus. Stone hopes to examine the bear's brain, though gunshots to his head — two of five bullets fired by police — make that difficult, he said.
Wildlife experts said residents should not fear a repeat of the rare tragedy. Throughout North America, the normally timid bears have attacked humans just 50 times in the last century, said Rogers, who holds a doctorate in animal behavior.
The attack on the infant represented only the second killing of a human by a bear in an eastern U.S. forest. In May 2000, an adult female bear mauled a teacher to death near Gatlinburg, Tenn., in Great Smoky Mountain National Park.
There were no witnesses, and no cause was determined. The remaining attacks occurred in remote parts of Canada and Alaska, where bears aren't accustomed to seeing people, Rogers said.
The bear that killed Esther had a mixture of wild vegetation and people food — even aluminum foil and fruit labels — in his stomach, showing it was familiar with people and their garbage, Stone said.
Past problems with bears in New York include basic nuisance complaints, such as bears going through garbage cans, tents or bird feeders, he said. Last August, a bear jumped through a screen door after smelling chocolate chip cookie ingredients in an Adirondack cabin, then knocked down the woman inside while trying to escape, Berchielli said.
"Bears are just big chickens," Rogers said. "They've survived by running without question. The littlest hound can chase the biggest bear up a tree."