A smalltooth sawfish (Pristis pectinata) at an aquarium in Georgia. Photo by: Diliff.
Although all seven species of sawfish are nearly extinct, scientists have spent little time studying these vanishing species. However that is changing as a new study in Current Biology sheds light on the sawfishes’ most distinguishing feature: its long toothed snout, which gives the fish its name.
“I was surprised to see how skilled sawfish are with their saw,” said co-author Barbara Wueringer of the University of Queensland in a press release. “They use their saw to impale prey on the rostral teeth by producing several lateral swipes per second.”
Before Wueringer’s research, it was generally assumed that sawfish used their snout to sift through sand seeking prey. However, studying sawfish in captivity, Wueringer found that the sawfish wielded its weapon far more dramatically.
“Their strikes were sometimes strong enough to split [dead] fish in half,” Wueringer says, who observed with hidden cameras how sawfish in captivity attacked the already-dead fish thrown to them. After bifurcating their prey, they would employ the saw to swipe the fish onto the floor and only then eat.
But this is not the only application for the sawfishes’ snout. Past research by Wueringer found that the snouts sport thousands of electroreceptors, which allow the sawfish to detect prey by sensing their electric fields. In addition, the skin is pocked by tiny canals that sense movement in the water. These attributes allow the sawfish to locate prey in their lightless habitats. Once located, prey is quickly dispatched with the saw.
“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 says.
Found mostly in the tropics, the sawfish, a part of the ray family, swim between freshwater and seawater. Unfortunately every one of the seven species of sawfish are classified as Critically Endangered by the IUCN Red List, the highest category before extinction. Sawfish have been decimated as by-catch, since their saw snouts easily get caught in fishing equipment. In addition, the group has been over-harvested for food, traditional medicine, as curios, and for captivity in aquariums. Their future looks bleak as many have vanished from known habitats and populations are highly fragmented. Despite their rarity, some sawfish are still targeted by fishermen and lack any protection whatsoever.
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