Blue Bottle Jellyfish

Blue bottle jellyfish is so-called in Australia and New Zealand where it is also commonly known as Blue Bubble Jellyfish. Elsewhere in the world, this creature is usually called the Man of War or Portuguese Man o' War, since it resembles a Portuguese battleship with a sail.

The blue Bottle Jellyfish (Physalia utriculus), although commonly mistaken for a jellyfish is not a jellyfish at all. It is not even a single organism. It is, in fact, a colony of four minute zooids. These four zooids are highly specialized and perform different functions. They cannot live independently, as they can only serve one single function, but together, as a colony of four zooids, they can function as well as a unified organism.

One of the four zooids performs the function of an air bladder. It allows the blue bottle jellyfish to float. It may be 9 to 30 centimeters in length and may extend as much as 15 centimeters above the surface of the water. In the event that the blue bottle jellyfish is being attacked from the surface of the water, this air bladder is capable of deflating and allowing the blue bottle to sink under the water and escape the attack.

Below the main body of the blue are its tentacles. They are an average of one meter in length, but under certain conditions are known to grow as long as 50 meters. Each of these tentacles is lined with numerous nematocysts that contain the highly toxic venom of the blue bottle. When the tentacles come in contact with a prey, the nematocysts are activated and the toxin is infected into the flesh of the prey. It is sufficient to kill small prey like shrimp and young fish. The tentacles then help transport the food towards the digestive polyps, the gastrozooids, another type of polyp that digests the food with powerful enzymes. These venom filled tentacles also protects the blue bottle jellyfish from large predators. The toxins are strong enough to paralyze large fish, if not kill it, and enable a getaway.

When the blue bottles come in contact with humans, they react in exactly the same way as they would when faced with danger, and they sting us. Blue bottle jellyfish stings are known to be extremely painful. The sting can cause an extremely painful rash which doesn't subside for at least an hour after the sting. While the sting in itself does not cause any major effects in the human body, a sensitive individual who is prone to allergies can have an extreme reaction to the toxins in the blue bottle's venom. An allergic reaction can lead to fever, heart and lung failure and may even lead to death, even though it is extremely rare. Additionally, if a person has received multiple stings, he may be at risk of very severe pain and will require immediate medical attention. It is also important to remember that detaches tentacles of a blue bottle are also capable to delivering a sting for a few hours after detachment.