The lion’s mane jellyfish is a large marine creature. Understanding this animal is important, particularly concerning its potential interaction with humans.
Identifying the Lion’s Mane Jellyfish
The lion’s mane jellyfish, scientifically known as Cyanea capillata, is one of the largest jellyfish species in the world. Its bell is broad, flattened, and ranges in color from milky white or pale pink to brick red, reddish-purple, or yellowish-brown. Individuals found in colder Arctic waters can have bells up to 2.4 meters (about 8 feet) in diameter, though those in warmer regions like the southeastern United States are significantly smaller, with bells around 13-15 cm (5-6 inches) across.
Trailing from its bell are numerous long, hair-like tentacles, resembling a lion’s mane. These tentacles are arranged in eight clusters, with each cluster containing 70 to 150 tentacles. While the longest recorded tentacles reached 36.6 meters (120 feet), most average between 1.8 to 2.4 meters (6-8 feet), and can be difficult to see in the water. These jellyfish primarily inhabit cold, boreal waters of the Arctic, North Atlantic, and North Pacific Oceans, and are often seen in late summer and autumn when currents sweep them closer to shore.
The Sting and Its Effects
Lion’s mane jellyfish tentacles are densely covered with specialized stinging cells called nematocysts. When triggered by touch, these microscopic capsules rapidly fire a harpoon-like structure that injects neurotoxins into the skin. This venom, designed to paralyze prey, causes various symptoms in humans.
Upon contact, individuals experience immediate, sharp pain, stinging, or a pricking sensation, followed by localized redness, itching, and welts or blisters. The severity of the sting can vary depending on the amount of skin contact and an individual’s sensitivity to the venom. While most stings result in localized discomfort, more extensive contact can lead to muscle cramps, irritation, and even breathing difficulties. Although the sting is painful and can cause severe reactions, it is rarely fatal for healthy individuals. However, the intense pain could potentially lead to panic, which might pose a drowning risk in deep water.
First Aid and Prevention
Prompt first aid can help manage symptoms after a lion’s mane jellyfish encounter. First, carefully remove any visible tentacles adhering to the skin using tweezers, gloved hands, or the edge of a credit card. It is important to avoid rubbing the affected area, as this can cause more nematocysts to fire and release additional venom.
Rinsing the sting area with vinegar helps deactivate unfired nematocysts and prevent further venom release. After removing tentacles and rinsing, immersing the affected area in hot water, around 45°C (113°F), for 30 to 40 minutes or applying a heat pack to inactivate the toxins and reduce pain. Over-the-counter pain relievers ibuprofen or acetaminophen, and antihistamines for itching or swelling, may also provide relief.
Seek medical attention if symptoms include difficulty breathing, dizziness, widespread pain or swelling, or if the pain persists for several days. To prevent stings, it is advisable to be aware of local jellyfish advisories, exit the water if lion’s mane jellyfish are sighted, and avoid touching any jellyfish, even if they appear stranded on the sand, as their tentacles can still sting. Wearing protective clothing like a wetsuit can also offer a physical barrier against stings in known jellyfish habitats.