Sunday, December 12, 2010

Lion's Mane Jellyfish!

C. capillata – Lion’s Mane Jellyfish!



Kingdom: Animalia

Phylum: Cnidaria

Class: Scyphozoa

Order: Semaeostomeae

Family: Cyaneidae

Genus: Cyanea

Species: C. capillata

C. capillata, more commonly known as the lion’s mane jellyfish, is the largest species of jellyfish known. It lives mainly in cold, northern waters of the Arctic, north Atlantic, and north Pacific, and cannot cope with warmer waters. They have a preference for surface waters (less than 20 meters deep), so you would be having a rather bad day if you were shivering your butt off in the ocean of the northern Atlantic only to then get stung by one of these critters. Their taxonomy is not completely agreed amongst zoologists; some think that all species within the genus should be considered as one. Lion’s mane jellyfish are given their name because their ostentatious tentacles remind one of a lion’s mane.


Lion’s mane jellyfish are capable of growing to a bell diameter of 8 feet, but they vary in size greatly, those found in lower latitudes are normally smaller than their northern counterparts (most likely due to the fact that the lion’s mane thrives in cold waters). Their tentacles can grow as long as 90 feet, and are very sticky. There are about 100 tentacles to a cluster. The bell is divided into eight lobes, making it look like an eight-pointed star. Each lobe possesses a cluster of 60 to 130 tentacles at the margin of its jelly-like body. A tangled and coloured arrangement of arms comes from the center of the bell. The size of the lion’s mane also dictates its coloring: larger types are often crimson or purple, whereas smaller ones are orange or tan.

Form and Function

The diet of the lion’s mane jellyfish consists typically of zooplankton, small fish, ctenophores, and moon jellies. The mouth opens into the gastrovascular cavity, which communicates with the tentacles. The mouth is surrounded by a number of oral arms that help in transporting the food to the mouth. Prey is drawn into the gastrovascular cavity, and gland cells discharge enzymes that enable extracellular digestion. Predators of the lion’s mane jellyfish include seabirds, large fish, and sea turtles. Their locomotion is enabled by contractions of the bell, which expel water from the oral side. These contractions are opposed by the compressed mesoglea and the elastic fibers with it. Generally, the jellyfish has to contract several times and then move upward before sinking slowly. The lion’s mane jellyfish does not have a nervous system (instead they have a nerve net, a complex of nerve cells that form two interconnected nerve nets), respiratory system, circulatory system, or an excretory system (ameboid cells carry undigested food particles to the gastrovascular cavity, where they are expelled with other indigestible substances). Lion’s mane jellyfish have four different stages in their life span of a year: a larva stage, a polyp stage, an ephyrae stage, and a medusa stage. They are capable of reproducing asexually in the polyp stage and sexually during the medusa stage. A female lion’s mane jellyfish carries fertilized eggs to a tentacle where they hatch into larvae. As the larvae mature, the mother deposits them on a surface where they grow into polyps. The polyps reproduce asexually, creating stacks of ephyrae. The ephyrae break off from their stacks, and they grow into medusa jellyfish. The lion’s mane jellyfish protects itself from predators by delivering a painful sting which can cause severe burns. They do this by using stinging cells called nematocysts which are located on their tentacles. Nematocysts inject venom into the victim, and the venom can remain alive even after it leaves the lion’s mane. Sometimes, even when the jellyfish is dead, it can still sting if there is moisture present in the


Impact on Humanity

Lion’s mane jellyfish are an important link in the marine food web, as they are food sources for some species of large fish, which are eaten by humans. Another impact is obvious: if a human were to aggravate a particularly hostile lion’s mane, their nematocysts could penetrate the skin and inflict serious damage. It is certainly not comforting to know that run-ins with lion’s mane jellyfishes are fairly common, especially when seasonal conditions boost their populations.

Primary Source Article

Swarms of lion’s mane jellyfish have been flocking to the British Cornwall coast, thought to be because of the flourishing numbers of plankton, a major part of the lion mane’s diet. The new arrivals pose a threat to tourists who wish to take a dip in the sea, as their toxic sting can cause muscle paralysis, which can lead to suffocation and a heart attack. Andy Pearson first spotted the invasion after being surrounded by over 200 lion’s mane jellyfish off the coast. Lion’s manes are not native to the Cornwall coast, but due to the dropping ocean temperature, have migrated there, as they feel at home in cold water. While spectacular to behold, Pearson warns, getting to close to a lion’s mane must be avoided, as they are amongst the more dangerous of jellyfish, even though the sting itself, although nasty, is not fatal.



Works Cited

Lion’s Mane Jellyfish. (December 12, 2010). Retrieved from

Lion’s Mane Jellyfish. (December 12, 2010). Retrieved from

Lion’s Mane Jellyfish – Cyanea capillata. (December 12, 2010). Retrieved from

Lion’s Mane Jellyfish. (December 12, 2010). Retrieved from's_mane_jellyfish

Lion’s Mane Jellyfish. (December 12, 2010). Retrieved from


  1. sorry about the green randomly changed it and I didn't know how to change it back

  2. Annoying, yes....but I understand!