Australasian Science: Australia's authority on science since 1938

Demystifying a Sea Monster

Credit: David Wachenfeld, Triggerfish Images

A freshwater sawfish rests on the bottom. Credit: David Wachenfeld, Triggerfish Images

By Barbara Wueringer

The use of the sawfish’s saw has been widely speculated upon, but a recent study has finally revealed its dual purpose.

Barbara Wueringer is now an Adjunct Senior Research Fellow at James Cook University’s School of Marine and Tropical Biology. The study was conducted at both the University of Queensland and the University of Western Australia.

The full text of this article can be purchased from Informit.

Catching prey might be one of the most difficult tasks that animals face every day. This task can be even more difficult for aquatic predators, whose prey can escape into three-dimensional space.

Sharks and rays have developed a variety of hunting strategies, but one of their close relatives, the sawfish, has an adaptation that might simplify this daunting task – its saw. Our research has found that the saw is both a sensor to detect the sawfish’s prey and also a weapon that is used to dismember prey. The findings have changed our understanding of the hunting skills of sawfish.

But let’s take a step back and find out what a sawfish exactly is. Sawfish are rays. As such, they belong to the group of cartilaginous fishes and are closely related to sharks. They are some of the few rays that possess a shark-like body.

Sawfish also possess a long rostrum or snout – the “saw” – which bears teeth on its lateral edges. These teeth have evolved from the skin teeth, or denticles, of sharks and rays. If you have ever touched a shark or ray you will know that their skin feels like sandpaper.

Sawfish are often confused with swordfish. Swordfish are bony fish, which means that their skeleton is made of bone. They live in the open oceans and their close relatives are marlins and sailfish.

Sawfish, on the other hand, are closely related to shovelnose...

The full text of this article can be purchased from Informit.