Jellyfish Day

Jellyfish Day is a holiday dedicated to the mysterious and unusual world of invertebrate marine life. Celebrated every year on November 3, this day is the perfect opportunity to discover more about these fascinating sea creatures.

History

Jellyfish have existed on Earth even longer than dinosaurs and have survived every cataclysm that has occurred. Scientists have determined that jellyfish first appeared over 500 million years ago, as confirmed by fossils discovered in Utah in 2007 that are estimated to be 505 million years old.

Jellyfish have always seemed unusual and special due to their translucent bodies, tentacles of varying lengths, and complete absence of bones or complex organs. For a long time, scientists were unable to classify these creatures, as they didn’t fit established categories.

Interesting Facts

• Jellyfish could not be studied in detail until the invention of the microscope.
• In 1866, zoologist Ernst Haeckel published General Morphology of Organisms, describing the evolution of animals, including jellyfish.
• Haeckel believed jellyfish separated into a distinct class early in the development of life, making them unique among animals.
• Jellyfish need only a minimal amount of oxygen, reproduce rapidly, and shrink in size when food is scarce.
• About 95% of a jellyfish’s body is water; the remaining 5% is called mesoglea, which is made up of nerves, muscle, and protein.
• Jellyfish can be beautiful, glowing in different colors, but some species are also poisonous.

How to Take Part

There is a wealth of information about jellyfish in films, books, and articles, so use this day to learn more about these creatures. A great way to celebrate Jellyfish Day is by visiting an aquarium with family or friends.

When is Jellyfish Day in 2025?

Jellyfish Day is observed on November 3 each year.

Observations