Kategorie: News
Research shows why mantis shrimp do not suffer any damage despite their powerful strikes
Mantis shrimp are known for their extremely powerful strikes, which can destroy snails, mussels and even aquarium glass. Their clubs can reach the force of a small-calibre bullet, creating shock waves that make their attacks even more effective. But why does the shrimp itself remain unharmed?
A research team has now taken a closer look at this question. Previous studies had already shown that the surface of the club where it makes contact is highly mineralised and contains a special sugar compound that makes the material more resilient. ‘When the club hits its target, it causes strong pressure waves, and when the bubbles collapse, additional shock waves in the megahertz range are generated,’ explains Horacio Espinosa of Northwestern University in Evanston. He is co-author of the study, which has now been published in the journal Science.
The new study revealed that the club consists of two crucial structures: a highly mineralised fishbone pattern on the surface and spirally arranged chitin fibre bundles inside. This combination increases the club's striking power, dissipates shock waves in a targeted manner and prevents damage to tissue and nerves.
The findings could contribute to the development of new protective materials in the future, for example for helmets or sound-filtering equipment. Mantis shrimp are not the only crustaceans to use shock waves – pistol shrimp also use this technique to stun or kill prey fish with a loud bang.
Regarding the study:
www.science.org/doi/10.1126/science.adq7100
www.mccormick.northwestern.edu/research-faculty/directory/profiles/espinosa-horacio.html
Video on the topic:
www.youtube.com/watch?v=5WWvulAC_zU
More information about mantis shrimp
Mantis shrimps (Stomatopoda) are fascinating sea creatures that live in tropical and temperate waters. With a length of up to 35 centimetres and often bright colours, they are not only visually impressive but also remarkable hunters.
There are two main hunting strategies used by mantis shrimps:
Spearers: These crabs have pointed, spiked tentacles (dactyls) that they use to spear prey such as fish or shrimp at lightning speed.
Smashers: They have club-like tentacles that they use with tremendous speed and force to smash the hard shells of snails or clams. Their strikes reach incredible speeds and generate forces of up to 1,500 newtons, comparable to a small-calibre rifle shot. The resulting cavitation – the sudden collapse of vapour bubbles in the water – creates additional shock waves that increase the effectiveness of the attack.
Another outstanding feature of mantis shrimp is their highly developed eyes. Each eye consists of up to 10,000 individual ommatidia and is able to perceive more than 100,000 colours as well as ultraviolet and polarised light. This extraordinary visual ability enables them to detect their prey with precision and to communicate with other members of their species.
Mantis shrimp are territorial animals and vigorously defend their territory against intruders. When fighting with other mantis shrimp, they follow strict rules to avoid serious injury: the opponents take turns striking, with the blows being reduced in intensity and the attacked individual often trying to cushion the attacks with its tail carapace.
Their reproduction is also remarkable. The female carries the fertilised eggs as a compact package under her chest area and turns them regularly to aerate and protect them from fungal infection. After hatching, the larvae initially remain in the mother's protective cavity before they turn into plankton and finally settle on the seabed as young animals.
Due to their impressive abilities and unique appearance, mantis shrimp are of great interest to both marine biologists and divers.
Further information:
Biology Report DiveInside: Mantis shrimps (german article)