There are around 2,000 different species of jellyfish in the world, and the most common being the big, colorful ones found in warmer coastal waters.
There are four listed jellyfish that are categorized by the shape of their body and the way they behave. Jellyfish prefer being in open seas rather than in inland or coastal waters.
Jellyfish are classified as invertebrates, and together with gorgonians, anemones, and corals belong to a group known as cnidarians.
Jellyfish group has stinging cells that they effectively use in catching prey and to defend themselves. This is because these cells are filled with capsules that pack a fatal poison.
Despite the name, jellyfish aren’t actually fish. Jellyfish are classed in a group of their own and are entirely different from other animals on earth.
The jellyfish’s body is mainly made up of 95% water, and because of this, they can easily pull off a perfect camouflage. Their body also consists of a non-living substance that is jelly-like and is known as mesoglea.
Even though their mobility is propelled by the regular repetitive motions of their umbrella, they still depend solely on the sea’s currents.
The body of the jellyfish is subdivided into three main sections: the umbrella, oral arms, and the tentacle (that houses the stingers).
The capsule opens when prey or animal comes in contact with the jellyfish, and the filaments have discharged that stick onto the prey, injecting the poison.
The jellyfish also has an internal cavity where digestion takes place. This area has an aperture that serves as both the mouth and the anus.
- Scientific Name: Cnidaria Scyphozoa Aurelia
- Kingdom: Animalia
- Phylum: Cnidaria
- Class: Scyphozoa
- Family: Cyaneidae
- Order: Semaeostomeae
- Type: Cnidaria
- Diet: Carnivore
- Lifestyle: Group
- Size: 12-200cm (5-78.7in)
- Weight: 20-400g (0.7-14oz)
- Top Speed: 5mph (8km/h)
- Lifespan: 1-5 years
- Conservation Status: Categorized as “Least Concern”
- Colour: Blue, White, Pink, Purple, Red, Yellow, Green, Orange
- Skin type: Very smooth
- Favorite food: Fish
- Habitat: Shallow and Deep Oceans
- Average litter size: 100
- Main Prey: Eggs, invertebrates
- Predators: Humans, sharks, squids, and Sea Birds
- Special Features: Jelly-like body with long, stinging tentacles
The jellyfish is a carnivorous creature, and despite is soft appearance, the animal is a master predator. It generally uses its tentacles to stun prey before feeding on it.
With the abundance of food, jellyfish can rapidly grow in size and procreate in large numbers.
However, when food is scarce, jellyfish become smaller. Despite how gelatinous the jellyfish is, they have very complex anatomy that is nevertheless very efficient.
Part of the invertebrate’s diet includes small crustaceans, zooplankton, small fish, and in some cases, other jellyfish.
Reproduction happens when male and female jellyfish fertilize (Sexual Reproduction) their eggs by releasing both eggs and sperm into the water.
The eggs then develop into little larvae that turn into new generations of jellyfish or polyps.
They settle on the sea beds where they eat and get big enough to feed on larger prey.
Jellyfish makes use of its tentacles and their stinging cells as defense and as a powerful weapon in capturing prey.
The nematocysts (poisonous cells) present in the tentacles release their filaments or harpoons when they come in contact with prey or a threat, and the toxic substance is released.
The poison then weakens and paralyzes the prey or threat. The tentacles are used in catching and ingesting of captured animals.
Among jellyfish predators, the following have been identified: grey triggerfish, some whales (like the humpbacks) , the whale shark, ocean sunfish, turtles (most notably the leatherback sea turtle), seabirds (such as the fulmars), some crabs (such as the hermit and arrow crabs), some cnidarians such as anemones, certain nudibranchs (small mollusks without their hard shells), also feed on jellyfish. Some of these may use their stinging cells in their defense.
Studies have shown that some jellyfish are naturally bioluminescent. Meaning they are capable of producing their own light.
The box jellyfish can kill a human adult, so it’s best to be careful when in contact with them. Jellyfish don’t make use of their brain because they don’t have any, they also don’t have any hearts or eyes, and they’ve been around for over 500 million years of history. Today’s jellies are remarkably similar to their prehistoric ancestors.
Are you a pet owner? Do you have a Jellyfish as a pet? Do you have any observations or contributions? Kindly make use of the comments section.