Deadliest Sea Creatures
Saltwater Crocodile
The saltwater crocodile is the world's largest reptile and one of Australia's deadliest animals. It is the continent's only wild animal that actively hunts human beings which stray into its territory. These crocs reportedly kill hundreds of people each year. They usually grow to about 14 feet long, but some have surpassed 20 feet.-- Learn More
Box Jellyfish ("Boxes of Death")
A box jellyfish reels a snagged prawn towards its mouth. The box jellyfish species Chironex fleckeri has a deadly sting. These jellies, also known as sea wasps, grow to the size of a basketball and live in waters near Australia and the Philippines. They have 60 tentacles up to 10 feet long, containing thousands of stinging cells, which activate after touching human skin. Their stings can kill a person within three minutes; there have been 63 recorded deaths since 1884.-- Sea Wasp
Blue-Ringed Octopus
The blue-ringed octopus lives along Australia's southern coast. It is tiny, with a body only 2 1/2 inches in diameter, but it packs a toxic bite. Its saliva contains venom called cephalotoxin, a neuromuscular paralysing toxin. When bitten, a victim's nerve conduction is blocked, followed by paralysis, then death if no medical treatment is sought. There is no known antidote; several people have died from the bites.-- World Book: Blue-Ringed Octopus
Stonefish
The stonefish (frowning, center) is the most venomous fish in the world. It is well camouflaged in the ocean, because its brownish color often resembles a rock. It has thirteen sharp dorsal spines on its back, each packed with toxic venom. Someone who steps on a stonefish will feel intense pain for hours, temporary paralysis, possibly shock and even death. There have been no recorded human deaths in Australia due to the development of an antivenin in 1959.-- World Book: Stonefish
Great White Shark
These voracious predators can grow up to 21 feet long and weigh 7,100 pounds. White sharks have been known to attack humans and are often considered the most dangerous sharks. Other sharks that attack people are the tiger shark, bull shark and the oceanic white tip shark. Worldwide, unprovoked shark attacks have fallen from a high of 78 in 2000, to 58 in 2005.-- View Photos of Scary and Exotic Sharks
Sea Snake
There are 32 species of sea snake. Their venom is more toxic than that of land snakes, but sea snakes are shy and tend to stay away from people, so there is little risk. A small number of bites can be fatal to people.-- Learn More
Stingray
A spotted reef stingray rests on the sea bottom near Sharm el-Sheikh, Egypt. Stingrays possess a cartilagineous skeleton like sharks, and have a flattened body with a long tail armed with a barbed, venomous spine. When stepped on or disturbed, the stingray will swing its tail up. The tail barbs produce a sting like a snakebite. "Crocodile Hunter" Steve Irwin died in September 2006 after being struck in the chest by a stingray's tail barb.-- View More Photos of Stingrays
Puffer Fish or Blowfish
A yellow puffer fish inflates its body as it swims near the Galapagos Islands, displaying protective spines which, like most of its other tissues, contain the deadly toxin tetrodotoxin. Most puffer fish are poisonous; their toxin is 1,200 times more powerful than cyanide. Puffer fish are considered a delicacy in Japan and Korea.-- World Book: Puffer Fish
Irukandji Jellyfish
A fully grown Irukandji jellyfish lies next to matchsticks for size comparison in a lab in Cairns, Australia. The Irukandji is a type of box jellyfish. The stingers on its box and tentacles can cause a syndrome that can be fatal. Victims get severe backaches or headaches and shooting pains in their muscles, chest and abdomen. In rare cases, the victim suffers pulmonary edema. These jellies live in north Australian waters and along the Great Barrier Reef. -- Learn More
Flower Urchin
The small "flowers" on this urchin are tiny venomous pincers that can cause paralyisis and even death. Flower urchins have allegedly killed several people in Japan, although a report from WebMD states that documentation in general is sparse and death is probably very rare.-- Sea Urchins
Cone Shell
This is a poisonous cone shell with its proboscis protruding. This proboscis is a hollow feeding tube with a barbed tooth on the end. The cone shell injects venom through the tooth and into its prey -- usually fish and molluscs. The venom from one cone shell could, in theory, kill 700 people. Sting symptoms progress from numbness to breathing failure.-- World Book: Cone Shell
Great Barracuda
A great barracuda swims on Bannana Reef near Key Largo, Fla. This barracuda species has been known to attack people, especially those who wear shiny, reflective objects. Barracuda attacks are rare, however, as are fatalities. These fish do have two sets of razor-sharp teeth and can swim up to 36 mph.-- Field Guide: Great Barracuda
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