Even so, fatal attacks such as the one that killed television star and naturalist Steve Irwin are extremely rare.
Irwin, 44, died today when a spear-like stingray barb pierced his chest while diving on the Great Barrier Reef, and it's believed he may have had a heart attack.
Third stingray death
Irwin's death was only the third known stingray death in Australian waters, said shark and stingray expert Victoria Brims from Oceanworld Manly, in Sydney.
She said Irwin probably probably had an extreme allergic reaction to the stingray's venom.
A sting from a ray's tail caused a rapid deterioration of tissue.
A sting on the arm or leg can be painful but fairly harmless, but if the sting hits the heart it can result in a massive heart attack or a severe allergic reaction, Ms Brims said.
"Given his death appears to have been pretty sudden it was most likely some sort of allergic reaction," she said.
Attacks uncommon
Marine biologist Dr Meredith Peach said stingray attacks were uncommon.
"It is really quite unusual for divers to be stung, unless they are grappling with the animal and knowing Steve Irwin perhaps that may have been the case.
"Most stings would be on the legs or feet, it is very unusual to be stung on the chest.
"It is highly unusual, extremely unusual for people to die from stingray stings."
Stingrays are mostly gentle bottom-dwellers which live at depths of 30 to 60 metres in the warm waters of the Great Barrier Reef, growing up to four metres long and weighing up to two tonnes.
Stingrays will generally avoid people if left alone, and most stingray injuries occur when a person steps on one of the creatures, marine experts say.
Typically, all that results is a non-fatal gash to the legs.
100 species
Dr Peach, the author of the website www.sharkchic.com.au, said there were more than 100 species on stingray in Australian waters -
the largest measuring up to two metres across.
She said a much smaller stingray could still inflict a blow severe enough to pierce the chest.
Professor David Booth, a fish ecologist who dives regularly on the Great Barrier Reef, said being impaled by a stingray was a less common but still potentially deadly injury.
"Certainly the injuries I've seen have been penetrating wounds where someone has stepped on the animal," Prof Booth said today.
"I've seen a horrible one when the spine went through a guy's leg muscle. But the big ones have enough inertia in their body that if you go near them they can whip their tail around and get you.
"The lashing involves the tail coming back over the body on the top side and they are pretty accurate with their spine."
Prof Booth said multiple factors could have contributed to Mr Irwin's death, including being seriously injured while diving and rising to the surface too quickly.
"I wouldn't want people to think it is a risky activity, diving on the reef because of stingrays," Prof Booth said. "They are the least of the dangers actually."
Dangerous work
Wildlife filmmaker David Ireland said the barb that struck Mr Irwin could have been as deadly as a rifle bayonet driven into one of his vital organs.
Mr Ireland told Southern Cross Broadcasting working with stingrays was potentially very dangerous.
"They have one or two barbs in the tails which are not only coated in toxic material but are also like bayonet, like a bayonet on a rifle. If it hits any vital organs it's as deadly as bayonet.
"Wild animals are incredibly fast and a lot of animals have got very efficient defence mechanisms. We're very vulnerable as humans, working with animals like that."
Stingrays feed by sitting on the bottom of the ocean and by sifting out molluscs and shells as they pump water through their gills.
They feed on a variety of shellfish, molluscs, crustaceans and worms.
Treading on the dorsal surface by mistake or swimming too close above a ray can result in a reflex upward and forward swing of the
tail, according to Carl Edmonds' Dangerous Marine Creatures Field
Guide for Medical Treatment.
Stingrays can inflict either sword like lacerations or penetrate the body using their serrated spine.