Moon jelly and an aggregation of stingless golden jellyfish in a landlocked marine lake, Raja Ampat, West Papua, Indonesia
© Alex Mustard/Minden Picture
Sunshine on a moon jelly. World Jellyfish Day
Today we're celebrating World Jellyfish Day—even though these creatures are best described as otherworldly. Despite their alien qualities (not to mention their inability to vocalize), jellyfish have a lot to say to us about the history of life on Earth.
For example, species like the moon jelly and smaller golden jellies in our picture possess primitive eyes that only detect the presence of light, like the nourishing sunbeams they're chasing here. But some of their cousins, like the box jellyfish, boast several complex eyes with corneas and retinas. These differences help biologists understand how the human eye evolved to process such dazzling spectacles as the jellyfish's delicate dance.
Atlantic spotted dolphins near Santa Maria Island, Azores, Portugal
Group of giant cuttlefish in Spencer Gulf, off Whyalla, South Australia
Humpback whale mother and calf, Tonga
Crescent-tail bigeye fish in the Great Barrier Reef, Australia
A green sea turtle swims in the Pacific Ocean near the French overseas territory of New Caledonia
California sea lion in a forest of giant kelp, Baja California, Mexico
Mototi octopus, Lembeh Strait, Indonesia
Dolphin pod near Réunion island, Indian Ocean, overseas department of France
