The Lion’s Mane is one of the largest species of jellyfish characterised by its distinguishable mass of long, hair-like tentacles. The Lion’s Mane jellyfish has a large bell which is usually between 30-50cm (diameter) but can grow up to 200cm. At the margin of the bell, you can find hollow tentacles arranged in 8 groups with approximately 70 – 150 tentacles per group.The largest individuals, which are most commonly found in the artic ocean, can have tentacles extending to over 30m in length. This pelagic species prefers the colder waters of the northern hemisphere and can be generally found within the first 20 meters of the water column.

The tentacles have nematocysts (stinging cells) which the species use to stun its prey. It feeds on zooplankton, small fish and even other jellyfish. Once the prey is immobilised, the oral arms transport it to the mouth which is located on the underside of the bell. Sea turtles, some birds, larger fish as well as other jellyfish prey on Lion’s Mane jellyfish.

If you ever spot a Lion’s Mane along the Irish coast you can record it here. Be wary though and do not get too close. The sting from a Lion’s Mane can be very dangerous!

Image by Graham Pimlott