Monday, Sept. 4, 2006, was a dark day for humans and Dasyatidae alike. On that day, along the Great Barrier Reef off the coast of Queensland, Australia, Steve "The Crocodile Hunter" Irwin was killed while filming a documentary. While swimming over a large stingray (of the Dasyatidae family), the naturalist and television host died when the cartilaginous fish's barbed tail flicked upward and stabbed Irwin multiple times in the chest. A barb from the tail broke off the fish and lodged in the man's heart.
Before Irwin's accident, only two other people were known to have died from a stingray sting off the coast of Australia [source: Peatling]. What makes Irwin's death all the more tragic is that, despite their fierce and primeval appearance, stingrays are generally docile creatures. In fact, they're often called the "pussycats of the sea" [source: Williamson]].
Dasyatidae encompasses about 70 species of stingrays, varying in size from just less than one foot to up to 6.5 feet (30 centimeters to 2 meters) in diameter [source: McEachran and Carvahlo]. Stingrays are usually found in relatively shallow coastal saltwater regions, although some types are found in freshwater lakes and rivers in South America. The fish eat mollusks, shellfish and bivalves by using the strong grinding plates in their mouths to crush the shells of their prey. Stingrays only use their formidable stingers to defend themselves; they don't use them to capture prey. Members of the Dasyatidae family are typically gentle creatures, but Steve Irwin's improbable death showed that their stingers can inflict serious damage.
It's common knowledge that another potentially dangerous aquatic life-form, the jellyfish (family Cyaneidae), can still pose a threat through contact with nematocysts (stingers) found on its tentacles, even after the jellyfish is dead. These nematocysts bear toxins produced by the jellyfish, which it uses for defense and to capture prey. A lifeless jellyfish washed ashore on a beach can still inflict pain on a person unlucky enough to step on it. Stingrays also produce toxins delivered through barbs on their stingers. This raises the question: Is a stingray's sting still lethal even after its death?
When Stingrays Attack!
To find out if a dead stingray can still kill with its stinger, we first need to explore how a stingray uses its tail to defend itself.
Aside from its large, flat, winglike body, its mouth, eyes and gill slits on its dorsal surface and its tail, a stingray is generally featureless. This serves the stingray well; it lies flat on the sandy bottom of its habitat and camouflages itself by blending in with the sea bottom. Since stingrays often dwell just offshore, humans frolicking on the beach can easily and inadvertently step on a hidden one.
When stingrays are stepped on, handled roughly, or spooked, their tails will whip forward toward their heads like a scorpion, or to the side. Toward the end of a stingray's tail (called its caudal appendage) lies its venom apparatus. Long spines -- measuring several inches long and typically thought of as what puts the "sting" in "stingray" -- lay within a grooved abscess in the tail known as the cuneiform area. These spines are essentially hidden from sight when the stingray is unthreatened. A stingray is always preparing for action, however; tiny barbs are housed within the spine. While these barbs are idling beneath the spine's surface inside the integumentary sheath, they're constantly being washed in the stingray's venom.
When threatened, the stingray begins its tail whip; the barbs on the spines tear through the thin tissue of the integumentary sheath, and the spines jut out at an angle that's nearly perpendicular to the tail. Once the stingray is in motion, its tail becomes a whiplike weapon with a poisonous nail sticking out of it. The stingray's spines are rigid -- and in some species, can actually pierce bone [source: Lovgren]. On the other hand, they're also brittle and can break off and lodge into any laceration they create. The venom, contained in the mucuslike coating over the barb, is introduced into the body through the wound (a process called envenomation).
It doesn't sound like a very pleasant experience, and it's not. It's usually not life-threatening, but it is painful. Still, it's possible to die from a wound inflicted by a live stingray, but what about a dead one?
Can a Dead Stingray Kill You?
It's possible to die from a wound inflicted by a dead stingray, but it's also highly unlikely. The movement of the tail is what brings the barbed spine to an erect position and causes the venomous barbs to tear through the integumentary sheath. In other words, there is no muscle controlling the spine or barbs; they become a threat as the result of the tail's movement, somewhat like the motion of a folding knife springing from its cradle with a flick of the wrist.
This means that a dead stingray shouldn't be able to create the laceration needed to envenomate a person -- unless it died while in a defensive stance. If the spine was erect and ready for destruction, but hadn't met its mark when the stingray died, then it would still present a threat if someone handling the dead stingray punctured his or her skin with the spine.
HowStuffWorks couldn't find any case in which a person was killed by a dead stingray. There have been reports of fishermen dying from contact with dead, and even frozen, venomous fish, however. Even after a stingray's death, the venom it produced while alive would still be a threat to humans.
A person is far more likely to suffer a painful injury and possible complications from contact with a spooked stingray than death. So, what can you expect if you happen to step on a stingray? First, look forward to tremendous pain. The laceration created by the barbed spine penetrating flesh can be painful enough on its own. However, it's the venom that seems to be the real cause of the pain at the site of the wound.
Stingray venom is serious stuff. In large enough doses, it can affect the heart's electrical functioning and either dilates or constricts blood vessels [source: Williamson et al.]. The venom won't make it to the heart in most cases; it will usually hang around the wound site, causing tissue necrosis, or cellular death. There is some relief available for the pain: Soaking the wound in very hot water has been shown to soothe the ache created by stingray venom. Bacterial infections are also common, so you may need to take some antibiotics in the event of stingray sting. It's also highly recommended that anyone suffering a sting from a stingray seek medical attention. Stingray venom persists without medical intervention; the damage it causes to the soft tissue doesn't go away on its own.
Ultimately, it's best to respect the "pussycats of the sea." After all, even the gentlest of pussycats will defend themselves when threatened.
Last editorial update on Jan 16, 2020 12:19:18 pm.
Related HowStuffWorks Articles
More Great Links
- Grenard, Steve. "Stingray injuries envenomation and medical management." Potamotrygon. Accessed February 22, 2009. http://www.potamotrygon.de/fremdes/stingray%20article.htm
- Lovgren, Stefan. "Giant river stingray found near Thai city." National Geographic. April 29, 2008. http://news.nationalgeographic.com/news/2008/04/080429-giant-stingray.html
- McEachran, J.D. and de Carvalho, M.R. "Dasyatidae; stingrays." from "The living marine resources of the Western Central Atlantic; volume 1: introduction, molluscs, crustaceans, hagfishes, batoid fishes and chimaeras." Food and Agriculture Organization of the United Nations. 2002. http://www.fao.org/3/y4160e/y4160e00.htm
- Meade, John L., MD. "Stingray envenomation: overview." eMedicine. November 19, 2008. http://emedicine.medscape.com/article/772683-overview
- Mebane, G. Yancey, MD. "Spines!" Divers Alert Network. January/February 1995. http://www.diversalertnetwork.org/medical/articles/article.asp?articleid=56
- Peatling, Stephanie. "'Crocodile Hunter' death extremely rare, caught on film." National Geographic. September 6, 2006. http://news.nationalgeographic.com/news/2006/09/060905-irwin.html
- Williamson, John A. "Venomous and Poisonous Marine Animals." UNSW Press. 1996. https://books.google.com/books?id=YsZ3GryFIzEC&q=stingray#v=snippet&q=stingray&f=false