PORTUGUESE CARAVEL: CHARACTERISTICS, HABITAT, REPRODUCTION - BIOLOGY - 2025

The Portuguese caravel is a colony that is made up of a group of diverse organisms and cells that specialize in different functions but that together contribute to the successful development of this living colony.

It was described for the first time by Carlos Linnaeus, who initially classified it as a jellyfish. However, with the advancement of technology and observation techniques, it has been determined that the Portuguese caravel is not a single organism, but multiple living beings associated with each other, with different functions.

Specimen of Physalia physalis. Source: Image courtesy of Islands in the Sea 2002, NOAA / OER.

This organism is capable of establishing symbiotic and commensal relationships with other living beings, such as fish for example. Likewise, it is not safe in the seas, since there are animals that constitute great predators.

These animals include the loggerhead turtle, whose skin is thick enough to suffer the effects of the tentacles. Similarly, some mollusks, such as gastropods, can be potential predators of the Portuguese man-of-war.

Taxonomy

The taxonomic classification of Physalia physalis is as follows:

- Domain: Eukarya.

- Animalia Kingdom.

- Phylum: Cnidaria.

- Class: Hydrozoa.

- Order: Siphonophora.

- Family: Physaliidae.

- Genus: Physalia.

- Species: Physalia physalis.

characteristics

Physalia physalis is a colony of organisms that is made up of a wide variety of cells, each with specific functions. These cells belong to the eukaryotic group, so their genetic material (DNA) is found in the cell nucleus, delimited by the nuclear membrane.

Likewise, because it is made up of different types of cells, it is also affirmed that it is a multicellular organism. Similarly, Physalia physalis presents, like most organisms of the phylum cnidaria, radial symmetry, which implies that the structures that make it up are arranged according to a central axis.

Physalia physalis has tentacles that are filled with millions of cnidocytes, which make up nematocysts that are responsible for inoculating the toxin to the victims.

When talking about complex functions such as digestion, reproduction, excretion and respiration, it can be said that this organism has structures that are capable of carrying out these processes on their own.

For example, the various colonial organizations that make up the Portuguese caravel are fully specialized in these functions. There are some that are responsible for digestion (gastrozoids) and others are responsible for reproduction (gonozoids), among others.

With regard to respiration, this occurs through a passive diffusion process in which the oxygen present in the water passes through the skin of the animal to access its cells and fulfill its various functions in them.

Regarding its behavior and life habits, specialists have established that on many occasions this organism is part of large groups near the coasts, especially during the breeding season. This differentiates it from other jellyfish, which have solitary life habits.

Morphology

Although many believe just by looking at a Physalia physalis specimen that it is a simple jellyfish, this is not entirely true. The Portuguese caravel is made up of several organisms that establish a colony and live in harmony, each performing specific functions.

This false jellyfish has a quite characteristic morphology, since it consists of a kind of sail that remains on the surface of the water. Tentacles in varying numbers that can extend up to 50 meters are detached from this species of sail.

In reality, the Portuguese man-of-war is made up of four types of organisms with well-defined and specialized functions: pneumatophore, dactylozoids, gastrozoids, and gonozoids.

Pneumatophore

It is recognized as the most obvious and visible part of the colony that makes up the Portuguese Caravel. It is also known as a float and it is the one that is above sea level. It is responsible for the movement of the animal, since thanks to the action of the wind it moves on the surface.

Its length is variable, locating specimens whose pneumatophore measures about 10 cm, up to others that reach 30 cm. It has a gelatinous consistency and is translucent, but not entirely transparent. In the glare of the sun, it presents a coloration whose tones range from bluish to purple.

Specimen of Physalia physalis. Note the color and shape of your pneumatophore. Source: Biusch

Likewise, the pneumatophore is full of some gases, among which oxygen, nitrogen and argon have been identified. Likewise, it has the ability to inflate at will by incorporating air inside. This is of great help in terms of its movement, since the more air it contains, the faster it will move across the surface of the sea.

Dactylozoids

They are purely defensive. They are in charge of protecting the entire colony. They make up the long tentacles that come off directly from the pneumatophore.

They are characterized by the fact that they are riddled with cnidocytes, which produce a toxic substance that has serious and harmful effects on whoever comes into contact with them. Cnidocytes produce a structure known as nematocysts, which is responsible for releasing and inoculating prey with venom.

Enlargement of an area of ​​the Physalia physalis. Source: Taro Taylor aka tarotastic

The dactylozoids are the organs with which possible threats are detected and thanks to the poison they carry they can defend themselves against any animal that may cause them harm.

Gastrozoids

They are called food polyps. These lack tentacles around the mouth.

Gastrozoids are the ones in charge of capturing the prey and processing it through the action of various enzymes.

Gonozoids

These are characterized by not having a mouth or tentacles. Its function is only reproductive. On the gonozoids, in the form of clusters, there are the gonophores that are dioecious, that is, there are female and male sex.

Habitat and distribution

The Portuguese caravel is an organism that cannot withstand low temperatures. Because of this it is found primarily in tropical and subtropical areas and in oceans and seas whose temperatures are rather warm.

The preferred habitat of this organism is the Indian and Pacific Oceans, as well as the Caribbean Sea. It is found to a lesser extent in the Mediterranean Sea.

Reproduction

The reproductive process of the Portuguese man-of-war is carried out by the gonozoids. It is important to mention that the caravel is hermaphroditic, that is, it will present gonozoids that are female and male.

In general, the breeding season is during the fall. It is common for a large number of caravels (more than a thousand) to be gathered for reproductive purposes. When the time comes, the gonozoids break open and are released from the colony, releasing the gametes they contain, eggs and sperm.

In water, the process of fusion and fertilization of gametes occurs. Therefore, it is correct to affirm that the Portuguese man-of-war has a type of external fertilization.

Once fertilization occurs, a small planktonic larva is formed from which adult caravels originate through a process of asexual reproduction such as budding.

It is worth noting that the reproductive success of this organism is determined by the number of caravels that participate in the mating ritual. To the extent that there are more of these, the more likely that reproduction is successful and that a considerable number of individuals will be generated that can give continuity to the species.

Feeding

The Portuguese man-of-war is a carnivorous heterotrophic organism, which feeds mainly on small fish, zooplankton, krill larvae and even some small crustaceans.

For the feeding process, the toxin that its cnidocytes synthesize and secrete is extremely important, since the Portuguese man-of-war uses it to paralyze and immobilize the prey and thus be able to manipulate it with complete tranquility and ease with the help of its tentacles..

Once the caravel catches potential prey and it comes into contact with the poison, it is paralyzed. Later, the prey is brought closer to the gastrozoids, which are responsible for processing and digesting food.

Gastrozoids have the ability to produce and release digestive enzymes. These are in charge of acting on organic matter, degrading it and disintegrating it until it becomes easily assimilable compounds.

Once the prey has been processed and the nutrients obtained have been absorbed, the wastes that will not be used by the animal are released by the gastrozoids, specifically through the mouth through which the food first entered.

Relations with other living beings

The Portuguese caravel is capable of establishing interspecific relationships with other species of animals. One such relationship, which has been fully studied and of which several examples have been established, is commensalism.

Commensalism can be defined as that interspecific relationship in which both participating species receive a benefit but do not need each other to survive. This means that both species can live independently of each other.

One of the species with which the Portuguese man-of-war establishes a well-known commensal relationship is the clownfish. Importantly, this species of fish has been shown to be immune to toxins synthesized and secreted by organisms of the phylum cnidaria.

In this sense, the clown fish swims freely between the tentacles of the Caravel without suffering any type of damage from them. The benefit of the fish in this relationship is the protection that the tentacles of the Caravel offer it against possible predators.

On the other hand, the Caravel benefits because the attractive colors of the clownfish cause various animals (potential prey) to approach it and in this way it can capture and feed on them.

Bite

As with many jellyfish, the cnidocytes found in the Portuguese man-of-war synthesize a powerful toxin that, when in contact with other animals, is capable of causing serious damage to different tissues and even death.

However, despite its negative reputation, its toxin can only cause death in vulnerable people. This group can include the elderly, children and people whose immune system is depressed or those who are prone to developing allergic conditions.

Symptoms

Among the symptoms and signs that appear when it comes into contact with the tentacles of Physalia physalis we can mention:

- Intense itching.

- Redness of the area. Linear markings can even be seen indicating unequivocal contact of the tentacles with the skin.

- Inflammation of the surrounding area.

- Burning and pain in the affected area.

- Allergic reaction to the components of the toxin.

First aid

At the time a Physalia physalis bite occurs, a series of measures can be applied that have been shown to be effective in counteracting its harmful effects. These measures include:

- Remove the remains of tentacles that may have been attached to the skin. Try not to have direct contact with the tentacles at all times. Remove them with the help of a utensil or object.

- Clean the skin with salty water. Never, under any circumstances, clean it with fresh water, as this only worsens the stinging effect of the lesions.

- Apply an ointment or cream that can mitigate the burning. Some specialists claim that cortisone-containing creams are highly effective in counteracting the discomfort caused by the tentacles of the Portuguese man-of-war.

If the signs worsen and the symptoms persist, it is advisable to seek the help of a specialist doctor who can prescribe more effective medications in the treatment of these bites.

References

1. Ruppert, EE & Barnes, RD, 1994. Invertebrate zoology (6th ed.). Fort Worth, USA: Saunders College Publishing.
2. Curtis, H., Barnes, S., Schneck, A. and Massarini, A. (2008). Biology. Editorial Médica Panamericana. 7th edition
3. Hickman, CP, Roberts, LS, Larson, A., Ober, WC, & Garrison, C. (2001). Integrated principles of zoology (Vol. 15). McGraw-Hill.
4. Martínez, M., Villena, M., Marín, I. and Monedero, J. (2010). Sting by Portuguese Caravel, a "jellyfish" something special. Clinical Journal of Family Medicine. 3 (2).
5. Risk YJ, Cardoso JLC, Haddad Jr V. Envenoming caused by a Portuguese man-of-war (Physalia physalis) manifesting as purpuric papules. An Bras Dermatol 2012; 87 (4): 644-45.
6. Williamson, JA, Fenner, PJ, Burnett, JW & Rifkin, JF, 1996. Venomous and poisonous marine animals: a medical and biological handbook. Sydney: University of New South Wales Press.