Researchers reporting in the March 6 issue of Current Biology have figured out how sawfishes use their “saws” (rostrums)–to stun and shred prey, among other things.
“I was surprised to see how skilled sawfish are with their saw,” said Barbara Wueringer of the University of Queensland. “They use their saw to impale prey on the rostral teeth by producing several lateral swipes per second.”
Unlike sawfishes in the wild, the animals she and her team caught on hidden cameras were fed on dead fish, “but their strikes were sometimes strong enough to split those fish in half.” The animals then proceeded to swipe their meals onto the floor and dig in.
Sawfishes don’t use their saws just to kill and manipulate prey, but also to sense their next mark in the first place. That’s contrary to other jawed fishes whose long “noses” are generally used for one or the other purpose, not both, the researchers said.
Wueringer’s team earlier found that the saws of freshwater sawfishes are covered in thousands of electroreceptors. Those tiny sensors enable sawfishes to detect the electric fields of other animals in their midst. Tiny canals in the skin covering the saw also allow them to detect water movements. The two senses together give them an edge as hunters in the dark and murky waters in which they live.