Man O' War (Physalia physalis):
- Also known as the Portuguese Man O' War
- Has a distinctive float or sail that can be up to 12 inches long and is filled with gas.
- The float is brightly colored, usually blue or purple, and serves to keep the colony afloat and catch the wind.
- Has long trailing tentacles that can extend up to 165 feet in length.
- The tentacles are armed with stinging cells called nematocysts, which can deliver a painful sting to humans and other animals.
- The sting of a Man O' War is not usually life-threatening, but it can cause severe pain, nausea, and respiratory problems.
Blue Bottle (Physalia utriculus):
- Also known as the blue Portuguese Man O' War or the by-the-wind sailor
- Has a smaller float than the Man O' War, usually around 2-3 inches long.
- The float is usually blue or purple in color.
- Has shorter tentacles than the Man O' War, typically around 10-20 feet in length.
- The tentacles are also armed with nematocysts, but the sting is generally less severe than that of the Man O' War.
Both Man O' War and blue bottles are found in warm ocean waters around the world. They are often seen floating on the surface of the water, and they can be a hazard to swimmers and boaters. If you see a Man O' War or a blue bottle, it is best to avoid contact with it and keep a safe distance.