Jellyfish populations tend to wax and wane as conditions and their food supply does. In many species, this oscillation occurs in a 20-or-so-year cycle.

Caribbean box jellyfish, animals that may appear to float through life aimlessly and don’t have a central brain, still have the ability to learn rapidly and retain information, new research has ...

The jellyfish specimens were found in the Burgess Shale, a fossil-rich site in the Canadian Rockies that provides a glimpse of life during Earth’s Cambrian explosion. Like other soft-bodied ...

But like other jellyfish, they are brainless, controlling their cube-shaped bodies with a distributed network of neurons. That network, it turns out, is more sophisticated than you might assume.