A moon jellyfish (Aurelia aurita), photographed in Cotuit Bay, Massachusetts. Photo courtesy of Eric A. Lazo-Wasem/Yale Peabody Museum, via GBIF

My usual winter preoccupation with all the bewildering things in heaven turned to Earth this year. To the sea, actually — I’ve been reading about jellyfish.

They’re strange.

In the Gulf of Maine, there are a lot of jellyfish, as in salt water worldwide, and two species are seen most commonly, Dr. Nick Record, a senior research scientist with the Bigelow Laboratory for Ocean Sciences in East Boothbay, told me when I asked him recently. They are the moon jellyfish (Aurelia aurita) and the lion’s mane jellyfish (Cyanea capillata).

These were most likely the globs washed up on beaches back in kid days that we called white jellyfish and red jellyfish. We warned one another not to touch the red ones because they sting; those were the lion’s mane jellies. The white ones, we said confidently, you could pick up. Probably those were moon jellies. I can’t actually remember any of my friends handling the white ones either.

The moon jellies look round from the top and are generally around a foot or so in diameter. Lined around the edge of their bells are short, fine tentacles they use to catch food. They sting, but normally it’s practically unnoticeable to humans.

A lion’s mane jellyfish, photographed in Boston Harbor in 2021. Photo courtesy of Kent McFarland, via GBIF

The lion’s mane jellyfish is generally larger than the moon jellyfish. A few summers ago, unusually big ones — 5 and 6 feet in diameter — were seen in abundance along the Maine coast. Very large lion’s mane jellies can be 10 feet in diameter. Dangling underneath the lion’s mane’s body are up to a thousand tentacles.


This is the part where the strangeness starts to set in.

Jellyfish in the phylum Cnidaria have stinging cells called nematocysts, which they use to capture zooplankton or even small fish, and to defend themselves. Each nematocyst is made up of a pouch with a tiny harpoon-like needle inside. The cell is triggered mechanically, turning inside out and launching the harpoon with an explosive force of 40,000 Gs, according to marine biologist Lisa-Ann Gershwin. In the pouch, covering the harpoon, and inside the hollow harpoon is venom containing a complex of poisons, including neurotoxins.

Each thin tentacle on the lion’s mane jellyfish is up to 100 feet long and is covered with as many as 250,000 nematocysts.

The sting is reportedly extremely painful for humans. It can lead within a few minutes to symptoms such as weakness, vertigo, nausea, headache and muscle cramps, among others. Severe stings have led to difficulty breathing, tachycardia, muscle spasms and stiffness of back and joints.

No deaths from lion’s mane stings have been verified. But in the papers I’ve read, no researchers rule out the possibility, either, because the symptoms of the sting are similar to symptoms of “Irukandji syndrome” stings, which are administered by a genus of box jellyfish and are sometimes fatal. One of the most dangerous is the common Irukandji jellyfish, whose main body is generally just a few inches long, but whose four nematocyst-armed tentacles are about 4 feet long and as fine as spider silk. Irukandji jellyfish live primarily in the tropics and Southern Hemisphere.

A well-known — if less often seen — jellyfish in the Gulf of Maine is the Portuguese man-of-war, which also can inflict dangerous stings. But stranger than its nematocysts is the fact it isn’t really a single organism, the way we think of a cat or fish or human as a single animal. Instead, jellyfish in the order Siphonophora are made up of a “colony” of unique beings (called “persons” by the biologists) that function together as a single creature. The biologists do not agree on whether the Portuguese man-of-war is one whole animal or many animals together.


Not to put too fine a point on it, but the problem of whether the universe is one, single whole or a collection of many things has occupied philosophers for thousands of years. It looks like the marine biologists are now catching up.

Jellyfish reproduce in an enormous variety of ways: sexually and asexually, hermaphroditically and dioeciously, and clonally. Like some other animals, individuals of some species can transform between male and female. Their life phases in some cases take such completely different forms that phases of the same animal have been mistakenly categorized as different species.

The pea-sized “immortal jellyfish” (Turritopsis dohrnii), which lives in waters around Japan and the vicinity of the Adriatic Sea, theoretically never actually dies. When the mature jellyfish is injured, its cells disperse in the water, but do not decompose. They come back together to form a new larval-stage body and begin another life cycle of the same organism. The biologists call that process “transdifferentiation.”

This strange natural fact was a launching point for me, who has spent most of a lifetime puzzling over what in the holy hell is going on here. What if T. dohrnii is a metaphor nature made to explain something about itself, the way it made spring, summer, fall and winter look suspiciously similar to birth, youth, adulthood and old age?

Dr. Record — to whom you can report your jellyfish sightings jellyfish@bigelow.org for a citizen science project— likened jellyfish to space aliens in a magazine article a few years ago.

There is more in heaven and on Earth — and in the sea — than is dreamt of in our philosophy.

Dana Wilde lives in Troy. You can contact him at dwilde.naturalist@gmail.com. His book “Winter: Notes and Numina from the Maine Woods” is available from North Country Press. Backyard Naturalist appears the second and fourth Thursdays each month.

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