Box jellyfish, chironex fleckeri, are the most venomous marine animals known to man. They measure 10 feet (3 meters) long and weigh up to 4.4 pounds (2 kilograms). They are pale blue and transparent in color, and get their name from the cube-like shape of their bell. Box jellyfish have 6 eyes on all 4 sides of their bells, although it is uncertain how they process what they see as they do not have a central nervous system. They also have up to 15 tentacles growing from each corner of their bell that have about 5,000 stinging cells each.
Box jellyfish can be found primarily in the coastal waters off of Northern Australia as well as throughout the Indo-Pacific. They prefer to inhabit river mouths, estuaries and creeks. They do not have any gills or organs to breathe, and will sleep on the ocean floor from 3 pm to dawn. Unlike other jellyfish that merely drift, box jellyfish have developed a way to travel wherever they want to go. They will shoot themselves in a jet-like fashion, reaching speeds of up to 4.6 miles (7.4 kilometers) per hour.
The diet of box jellyfish consists of things like fish, crustaceans, and even other jellyfish. They use their venom, which causes heart, skin, and respiratory failure, to kill their prey. Surprisingly, their venom is not triggered by their stinging cells, but rather by the presence of a chemical on the outer layer of their victims. Since box jellyfish have eyes, some scientists believe that they actively hunt their prey while others insist that they are just passive opportunists that will wait and catch anything that wanders into their tentacles. Predators that box jellyfish need to watch out for include batfish, rabbitfish, butterfish, crabs as well as various species of sea turtles.
Box jellyfish reach sexual maturity around 70 days of age. They have a gestation period of 55 days, after which they will give birth to more than 1,000,000 offspring. Most will not make it, but those that do won’t live very long anyway. Box jellyfish have an average lifespan of less than 1 year.
Box jellyfish are responsible for more human deaths in Australia than snakes, sharks, and salt-water crocodiles combined. It is best to avoid them as most stings will result in death. If you are stung, pour regular vinegar over the tentacles (soak for at least 30 seconds) to inactivate the remaining sting cells and then seek medical help immediately. Hopefully, humans and box jellyfish can find a way to live with one another while keeping conflicts to a bare minimum. After all, such a unique species of jellyfish deserves to live and prosper just as humans do.
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