Lion'S Mane Jelly

Lion's mane jellyfish (Cyanea capillata) are named for their showy, trailing tentacles reminiscent of a lion's mane. They can vary greatly in size: although capable of attaining a bell diameter of over 2 m (6 ft 7 in), those found in lower latitudes are normally smaller than their far northern counterparts, with a bell about 50 cm (20 in) in diameter. Furthermore, larger specimens are typically further offshore than smaller ones. Juveniles are lighter orange or tan, but start to darken to red and purple as they age.

A fully grown adult lion's mane jellyfish has very few natural predators due to their large size and abundance of stinging tentacles. However, juveniles are preyed upon by seabirds, larger fish such as ocean sunfish, other jellyfish species, and most sea turtles. Anemones have been documented eating both adults and juveniles. The leatherback sea turtle feeds almost exclusively on them in large quantities during the summer season around Eastern Canada.

Lion's mane jellyfish remain mostly very near the surface, at no more than 20 m (66 ft) depth. Their slow pulsations weakly drive them forward, so they depend on ocean currents to travel great distances. The jellyfish are most often spotted during the late summer and autumn, when they have grown to a large size and the currents begin to sweep them to shore. Unlike most pelagic jellyfish, they are completely solitary and rarely travel in groups.

The lion's mane jellyfish uses its stinging tentacles to capture, pull in, and eat prey such as fish, zooplankton, and smaller jellyfish.

Human encounters with the jellyfish can cause temporary pain and localized redness. In normal circumstances, however, and in healthy individuals, the stings of the jellyfish are not known to be fatal; vinegar can be used to deactivate the nematocysts. If there is contact with a large number of tentacles, however, medical attention is recommended after exposure.