Even though different jellyfish species look and pulse differently, they all follow the exact same 'universal speed limit' for efficiency.
April 17, 2026
Original Paper
Measurements and modeling of swimming speed dependence on stroke frequency in scyphozoan jellyfish
arXiv · 2604.14491
The Takeaway
You might think a giant jellyfish and a tiny one would have completely different mechanics for how fast they swim. By using microelectronics to 'hack' the jellyfish's muscles, researchers found that almost all species share a nearly identical mathematical relationship between their pulse frequency and their speed. This suggests there is a universal mechanical 'sweet spot' that evolution has hard-coded into their bodies regardless of species. Surprisingly, most jellyfish don't actually swim at their most efficient speed in the wild, meaning their natural rhythms are likely evolved for something else, like catching prey, rather than just getting from point A to point B. It’s like finding out every car on Earth was built to get 40 mpg, but most drivers choose to go slower just to look for snacks.
From the abstract
Scyphozoan jellyfish exhibit the highest locomotive efficiency in the animal kingdom making them of particular interest in fluid dynamics and bioinspired robotics. Despite this prevalent analytical models of jellyfish swimming have been based on the swimming traits of hydrozoan jellyfish which utilize jet propulsion, rather than scyphozoan jellyfish which utilize paddling propulsive methods. Additionally, while stroke frequency is a driving variable in speeds achieved by undulatory swimmers, a s