Jellyfish digest their food, which consists of fish, shrimp, crabs and tiny plants, very quickly. If they didn't, they wouldn't be able to float, being weighed down by the large, undigested grub in their body.
Diet. The typical jelly eats small, swimming organisms called plankton: a mixture of tiny creatures like amphipods, copepods and krill. It also eats larval shrimps, crabs, fish and even other jellies.
The key to their survival is their ability to blend in with the ocean, which is achieved with bodies made up of 98% water. Not only that, but they also have no brain, blood, lungs, or heart.
Although they aren't picky about what they eat, their diet typically depends on their size. Some jellyfish are as tiny as a pinhead, so they can only feed on things like plankton, which are small, floating creatures. Larger jellyfish prey on bigger food sources such as fish, shrimp, and crab.
Lacking brains, blood, or even hearts, jellyfish are pretty simple critters. They are composed of three layers: an outer layer, called the epidermis; a middle layer made of a thick, elastic, jelly-like substance called mesoglea; and an inner layer, called the gastrodermis.
Throughout their lifecycle, jellyfish take on two different body forms: medusa and polyps. Polyps can reproduce asexually by budding, while medusae spawn eggs and sperm to reproduce sexually.
Like other jellies, box jellyfish have no brain, perceiving the world only through their nervous systems. Most jellyfish catch their prey without having either brains or eyes, just by floating transparently through the sea until prey run into their tentacles.
Grey triggerfish, ocean sunfish, seabirds, turtles, whale sharks, crabs, and whales eat jellyfish naturally. However, the main predators of jellyfish are usually other different types of jellyfish. The jellyfish is a pelagic fish that lives in the open ocean from the tropics to the Arctic Ocean.
Most jellyfish are “passive” feeders. This means that they float through the water eating whatever they happen to pass in the water and can fit in their mouths; anything from tiny shrimp and krill to small fish.
Do they have brains? No, jellyfish have no single centralized brain. Instead, they have radially distributed nervous systems that are adapted to their unique body plan.
On average, jellyfish will live anywhere from 1-3 years. However, certain species will only live a few days while others are able to live for a few decades. However, scientists are unable to say definitively how long jellyfish live due to their complex life cycles.
Most jellyfish live one to three years, but certain species can live from days to decades. Jellyfish have complex life cycles, beginning with fertilized larvae floating in the ocean.
When the medusa the immortal jellyfish (Turritopsis dohrnii) dies, it sinks to the ocean floor and begins to decay. Amazingly, its cells then reaggregate, not into a new medusa, but into polyps, and from these polyps emerge new jellyfish. The jellyfish has skipped to an earlier life stage to begin again.
Jellyfish may now be kept as pets in your own house thanks to the creation of specialized circular aquariums. Pet jellyfish can live for several years if they are properly cared for and fed.
Jellyfish don't usually mean to sting humans. They sting when you brush up against them while swimming or walking along the beach. Most jellyfish stings are harmless. But some jellyfish stings can cause serious harm.
They discovered that the jellyfish go through periods of inactivity at night, only pulsing about 39 times per minute, compared to about 58 times per minute during the day. Next, the team set out to prove that the animals had an increased arousal threshold during this period of decreased activity.
They may not have a brain, but jellyfish do get stressed out when handled roughly, scientists find.
Yep, that's right – if a jellyfish is sliced in half, the two pieces can regenerate and create two new organisms.
MYTH #2: Jellyfish "go after" people
Not true. Any contact with jellyfish is incidental. Humans are not on their menu, but when we are in their environment we can get in the way of their tentacles.
A jellyfish breathes by taking in oxygen from the seawater through its skin so as soon as it is on dry land it can no longer live.
Jellyfish sting for the same reason many sharks bite, they bump into something they think might be food and try and eat it. Are jellyfish conscious? Jellyfish have no brains and therefore are not aware of their own existence. So no, while alive they are not “conscious”.
These jellies can see blurry images. Not only do the complex eyes give a means to visually navigate their environments, but in some cases, they allow jellies to detect gravity. A crystal known as a “statolith” hangs under the eye, like a tennis ball hanging from a rope. As a result, they always knows which way is up.
Jellyfish are usually either male or female (with occasional hermaphrodites). In most cases, adults release sperm and eggs into the surrounding water, where the unprotected eggs are fertilized and develop into larvae.