*Stingray Protection Factor
MIAMI, Florida (CNN) -- A woman sunbathing on a boat died after a stingray leaped from the water off the Florida Keys on Thursday and struck her, officials said.
The dead stingray lies on the deck of a boat in Florida.
"It's just as freakish of an accident as I have heard," said Jorge Pino of Florida Fish and Wildlife Conservation Commission. "The chances of this occurring are so remote that most of us are completely astonished that this happened."
He said it was not clear whether the 55-year-old Michigan woman died from the blow to her head, from the ray's barb piercing her or from her fall backward.
The accident happened off the coast of Marathon Key, in the Florida Keys about an hour's drive south of Miami. The woman, who was with her husband and children, was taken to the Mariner Hospital in Tavernier, where she was pronounced dead.
Pino said he had seen stingrays leap into the air, but added, "it's very rare for them to collide with objects."
Results from an autopsy to be conducted by the medical examiner will be combined with witness statements and evidence from aboard the vessel to determine the cause of death, he said.
The spotted eagle ray weighed about 75 pounds, said Becky Herrin, a spokeswoman for the Monroe County Sheriff's Office.
The species, also called a leopard ray or bonnet skate, can measure up to 8 feet in length, with an 8-foot tail, and weigh up to 500 pounds, according to the Florida Museum of Natural History's Web site.
They tend to swim close to the surface and can leap out of the water when being pursued, according to the site.