Oceanography Fun Fact of the Week

The most venomous creatures in the world are not snakes but jellyfish, specifically the Cubozoa, commonly called box jellies or sea wasps. The largest species, Chironex fleckeri, can be as large as a basketball and trails up to 60 15-foot-long tentacles. It is a plague on northern Australian beaches, having killed about 100 people there. Death can come within 30 seconds of a serious sting, and survivors of less serious stings bear scars for life. Many beaches in northern Australia are protected with "stinger" nets.

Cubozoans are a separate class from the true jellyfish, known as scyphozoans, and are much more advanced. Square in cross-section, they are fast-swimming and have complex eyes, with a lens, cornea and retina, though they have no brain.

Bonus fact: sea anemones, the flower-like invertibrates often found in tide pools, also capture their prey by stinging it, with cells in their tentacles. They are unable to sting through human skin, such as on the hand, but be careful. Reportedly at least a few people who tried licking sea anemones have wound up in the hospital with their tongues so swollen they were unablet to breath.