J is for Jellies

What is a jelly?

Sea jellies are one of my favorite animals, which is a crowded field mostly populated by marine life. First, let's talk about what a jelly is not. In spite of being called jellyfish quite frequently, sea jellies are not fish! Fish are by definition vertebrates, & sea jellies have no bones at all. The blobby part of a sea jelly's body is called the “bell”, even though only some jelly bells are actually bell-shaped. The long thin strands are “tentacles”, where the jelly stingers are located. Some kinds of jellies have frilly “oral arms” stretching out from the bell. Some jellies use them to move food to the jelly's mouth. Some jellies cut right to the chase & have mouths on their oral arms! There are thousands of species of sea jelly & they are all wildly different from each other.The one thing all sea jellies have in common is that they are very cool. Today I will tell you a few reason why, and — because I'm a Jenny Nicholson fan— I will do so in the form of an internet-friendly numbered list:

Watercolor of a pink sea jelly playing an acoustic guitar with its tentacles. I will never be as cool as a sea jelly playing guitar.

Why Are Jellies So Cool?

  1. The collective noun for a group of sea jellies is a “smack”.

  2. Some sea jellies reproduce sexually, other asexually. This isn't divided by species: the lion's mane jelly can do both.

  3. The smallest jellies are about the size of a pea when fully grown.

  4. The largest jelly ever recorded had a bell 7 feet across, with tentacles 120 feet long!

  5. Sea jellies exist in every ocean on Earth.

  6. Sea jelly populations sometimes boom in a single location. This is called a “bloom”. Blooms can have devastating impacts on both the local ecology & things humans built.

  7. Sea jellies can thrive in both cold & warm water. They also do well in water that is acidic or polluted.

  8. Sea jelly populations are one of the very few ocean species that is responding positively to climate change.

  9. Some sea jellies are edible. They are considered a delicacy in many places. As sea jelly populations rise & blooms become more common, more people are trying to develop recipes for sea jelly.

  10. Upside-down jellies keep their tentacles angled up towards the sun, so the algae that that grows there gets enough light. The algae they grow accounts for 90% of their food. They are little marine farmers! They are also one of the very few types of sea jelly that anchors themselves in one place instead of moving through the water.

  11. Some sea jelly singers are too weak to hurt. Moon jelly stings have traditionally been used to treat arthritis.

  12. Some sea jellies are bioluminscent.

  13. Sea jellies don’t sting people on purpose- so don’t get too close! Some are harmless, some can be painful, & a few are deadly

Ink doodle of a happy red crab riding on a pink-purple-blue sea jelly.

And Another Thing

While we're on the subject: sea stars aren't fish, either. Sea Horses are, though; they are the slowest fish in the entire ocean! Humans are bad at naming things.

What do you think? Are sea jellies your new favorite marine life? Let me know on Mastodon or Ko-Fi! Have a fantastic day, draw something for my art challenge, see you next week!

Watercolor of a big yellow-green sea jelly with green & orange tentacles, having a nice swim.

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