Shrimp fists inspire new composite
Move over, Sugar Ray. The title of fastest punch in the animal kingdom firmly belongs to the peacock mantis shrimp, whose club-like appendages reach the speed of a .22-caliber slug, shatter clam shells with ease, and can slice human fingers to the bone.
Able to withstand thousands of strikes without breaking, the crustacean's "fists" have inspired a carbon-fiber composite material that is stronger and more durable than what is used by the commercial aircraft industry. Researchers created an architecture of carbon fibers to mimic the claw's shock-absorbing interior and then used impact testing to judge its toughness.
The mantis shrimp's design reigned supreme, with less denting and greater residual strength after impact. Potential applications could include aircraft and automotive panels, and athletic helmets and military body armor. The study was published online in the journal Acta Biomaterialia.
The extremely aggressive predator, which grows to about 2 to 7 inches long, smashes its way through crabs, mollusks and even the skulls of small fish.
Study author and materials scientist David Kisailus of the University of California at Riverside said, "Fishermen refer to them as 'thumb-splitters' for a reason."
Ravens can figure out who's the boss
Humans and other primates aren't the only members of the animal kingdom who can watch total strangers interact and figure out who's in charge. Ravens can do it too, according to a study in the journal Nature Communications.
Researchers at the University of Vienna said they had several reasons to suspect that ravens had the chops to understand the social hierarchy of unknown birds just by looking at them. For starters, ravens "are renowned for their relatively big brains," they wrote.
Among other things, these noggins allow them to switch between foraging in groups and looking out for themselves. Their brains also seem to help them keep track of social relationships that have nothing to do with reproduction (usually an animal's top priority). Some ravens have been known to console their buddies after losing a fight.
So the researchers selected 16 captive members of the Corvus corax species and rotated them through an aviary to see and hear other birds, though they remained physically separated. Then the researchers played audio of other birds from hidden loudspeakers.
The ravens reacted differently to dominance and submissive calls, showing their recognition of social hierarchy.