Stinky Communication Sounds Fishy

Herring send messages through farts and bubbles
We all know that passing gas in public sends a message. Usually that message is unwelcome. Among herring, however, communicating through flatulence may not be as fishy as it sounds.  Continue reading

The Eyes Have It

tuatara has three eyes

The tuatara, a New Zealand reptile, stands out in several different ways:

  • They have a third eye on the top center of their heads.
  • They have two rows of teeth on the top of their mouths that overlap the single row of teeth on the bottom.
  • They are able to hear, even though they have no external ear.
  • They have between 5 and 6 billion base pairs of genes in their DNA, compared to the 3 billion in human DNA.

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That’s Quite a Punch for Such a Shrimp

mantis shrimp most powerful force
Mantis Shrimp (Odontodactylus scyllarus)

The mantis shrimp may not be the largest creature in the ocean (hey, it’s a shrimp, after all), and its appearance can be a bit on the flamboyant side, so you probably wouldn’t count on it being much of a prizefighter. Appearances are often deceiving, though. This little guy may be in the lightweight division, but it packs the punch of a heavyweight.

The mantis shrimp has the ability to use its claws with formidable force. The claws, known as smashers, accelerate at the rate of 335,000 ft/sec2 — roughly the same rate as the acceleration of a .22 calibre bullet. The resulting impact of 1,500 Newtons is slightly less than the 1,900 Newtons of force needed for a human karate punch to split a 1.5-inch thick slab of concrete.

As if one punch were not enough, this is clearly a case where you get two for the price of one. Since the claws move so rapidly, they cause the surrounding water boils causes bubbles to form. Consequently, when the shrimp’s prey is struck by the smashers, that is just the beginning; the collapsing cavitation bubbles create a shock wave that is almost as powerful as the initial blow. The boiling is a result of the superheating of water due to the fast-moving smashers. This not only generates heat of several thousand Kelvin — almost equal to the surface temperature of the sun — but it also creates sonoluminescence — a very small spark of light that can only be seen with advanced scientific equipment.

These terrors of the sea tend to prey on snails and other shelled creatures, breaking them out of their otherwise-impenetrable fortresses with a quick one-two punch. They don’t make the best of pets. In captivity mantis shrimp have been known to break out of glass aquariums with a single strike.

To see a slow-motion video of a mantis shrimp strike, look here

Be sure to check out this excellent blog post about mantis shrimp from our friends at Science Alcove.

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