Animal Wonders #2
The Takeaway
A mantis shrimp is only about 10 centimetres long, but its punch reaches up to roughly 83 kilometres per hour. It is so fast that it creates a bubble in the water — and when that bubble collapses, the shock delivers a second hit.
Here is what makes it so remarkable, in brief.
The peacock mantis shrimp, a colourful species, smashes the shells of its prey with a club-like appendage and eats what is inside. In a study that measured the strike with a high-speed camera, the tip of the appendage reached a top speed of 23 metres per second — about 83 kilometres per hour.
Its acceleration exceeds 10,000 times the force of gravity. And all of this happens underwater. Speed like that on land would be one thing; doing it against the resistance of water is extraordinary.
Even more interesting is the “second hit” that the sheer speed produces. When the appendage moves that fast, bubbles form in the surrounding water — a phenomenon called cavitation.
When one of those bubbles collapses, it releases a shock of its own. So the prey is struck not only by the physical punch, but also by the bubble’s shock wave. A single swing lands twice.
How does it go beyond what muscle alone can do? The answer is a spring and a latch.
At the base of the appendage sits a hard, saddle-shaped spring. The shrimp slowly loads it with muscle power and stores the energy. Release the latch, and all that stored energy fires at once, snapping the appendage forward.
It is the same idea as drawing back a slingshot and letting go: the speed comes not from the muscle’s quickness, but from the mechanism.
A body small enough to hold, yet strong enough to crack shells, armed with a two-stage punch at 83 km/h underwater. Before it is a powerhouse, the mantis shrimp is a genius of engineering.
References
- Patek, Korff & Caldwell, “Deadly strike mechanism of a mantis shrimp” (Nature)
- University of California, Berkeley press release, “Mantis shrimp may have swiftest kick in the animal kingdom”
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