‘Man O War’
Physalia physalis
Film and Aquarium: Coral Morphologic
Original Soundtrack: Geologist

In this special installment of our Natural History film series, Geologist soundtracks a macroscopic view of a Portuguese man-o-war’s beautiful, yet highly venomous tentacles.

The man-o-war is often mistaken as a jellyfish, but this is not the case. It does not swim, but is instead propelled by the winds, tides and currents across the ocean’s surface. In fact, a man-o-war is not even a single organism, but an entire colony of organisms called siphonophores, that live together as a singular unit. They are found floating across all of the world’s tropical and subtropical oceans. Even more impressive is that the man-o-war colony is comprised of four different types of polyps, called zooids, that each serve a different purpose to the overall functioning of the colony.

The single pneumatophore is the largest of the zooids, and is easily recognized as the iconic purple or blue gas-filled bladder that bobs above the surface of the water. The pneumatophore acts as a sail for the rest of the zooids that trail beneath it.

The film is focused on the zooids that are found directly under the water’s surface. The curly-cued tentacles are comprised of a second type of zooid, dactylozooids, which are responsible for the severe stinging abilities of the man-o-war. These tiny dactylozooids are connected together as tentacles that collectively reach lengths of over 100 feet (30m). As can be observed in the film, these tentacles ‘fish’ by retracting in a recoiling motion. If a hapless victim is unfortunate enough to make direct contact, the dactylozooids will fire powerful harpoon-like nematocysts that deliver paralyzing venom directly into the victim. In the open ocean, this usually means small fish, but when close to shore, human contact is unfortunately inevitable.

The third type of zooid, which can be seen in the film as the shorter, whitish worm-like tentacles, are called gastrozooids. The gastrozooids act as the digestive mechanism for the captured prey. When prey is caught, the dactylozooid tentacles retract upwards to deliver it to the gastrozooids which then digest it.

A fourth type of zooid, the gonozooids, are responsible for reproduction.

Despite being one of the most dangerous organisms on the planet, the man-o-war is still susceptible to being eaten alive. Sea turtles, with their thick leathery skin, are immune from stings and can snack on man-o-wars with impunity. There is even a species of nudibranch (sea slug) that exclusively lives and feeds upon man-o-wars.

So while each of these individual zooids is biologically simple on their own, collectively they form a fully functioning unit that is capable of remarkable sentience. Take for example the man-o-war’s ability to avoid predation. When a threat is detected, the pneumatophore is capable of deflating itself and submerging. The pneumatophore requires being moistened with seawater from time to time, so the colony works in unison to roll the float from side to side in the water. Furthermore, Portuguese man-o-wars are seldom found floating singly. Rather, they usually travel in groups of hundreds to thousands, moving with the winds. Thus, if you see one man-o-war washed up on the beach, exercise caution swimming, as there may be more floating nearby!

If you do wind up stung by a Portuguese man-o-war, do not treat it like you would a jellyfish sting. Do not use freshwater, vinegar, or urine which may actually make the sting worse. Carefully (without using bare skin) remove any bits of remaining tentacles from the skin and flush with very hot water. The majority of pain should subside after an hour or so, but expect uncomfortable red welts that may scar. While deaths are rare, it is not uncommon for severely stung or sensitive individuals to go into shock. Seek medical attention as soon as possible in this scenario.

Interviews about the making of this film: Vice Magazine, Miami New Times

Tags: Animal Collective, Coral Morphologic, Geologist, Man O War, Morphologic Studios, Portuguese man-o-war

This entry was posted on Monday, May 2nd, 2011 at 8:41 pm and is filed under Natural History. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.