A new picture of the sawfish is
emerging. That saw is apparently way
more useful and effectively yielded than any had imagined. We have all seen aquarium displays that argue
an almost docile animal. Nothing of the
kind, of course.
Several swipes per second with a
weapon that also senses its targets is pretty scary.
Perhaps we will get some videos
showing off these skills soon. It will
be worth the effort and certainly will dispell our out of date ideas about this
critter.
Sawfishes sure can wield a saw
by Staff Writers
Sawfishes wouldn't be sawfishes if they didn't come equipped with long
toothy snouts-their saws. Now, researchers reporting in Current Biology, a Cell
Press publication, have figured out what they use those saws for, and it turns
out the answer is quite impressive. It might even help save the critically
endangered and incredibly elusive sawfishes.
"I was surprised to see how skilled sawfish are with their
saw," said Barbara Wueringer of the University of Queensland
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.
In the new study,
the researchers observed recently captured sawfishes in action. They watched as
those sawfishes tore into already dead fish and responded to weak electrical
fields that mimicked live, hidden prey.
"Now we know that sawfish are not sluggish bottom dwellers as
previously believed, but agile hunters that hunt in the three-dimensional space
of the water," Wueringer said.
What the researchers observed is contrary to what you might read in any
textbook, she added. The sawfishes' saw had been considered more like a rake,
used by the fish to sift through sand in search of something to eat.
Wueringer said this new view might even lead to changes in the fishing
practices that are allowed in prime sawfish territory, noting that the saw is
partly to blame for sawfishes' global decline: their saws are easily entangled
in fishing gear.
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