A video shot in Palau has captured what is believed to be the first footage of a fish using a tool.
In the video, which is described in the journal Coral Reefs, an orange-dotted tuskfish is seen digging a clam out of the sand.
The tuskfish then carries the clam over to a rock, and repeatedly throws the clam against the rock to crush it.
The footage was taken by a professor of ecology and evolutionary biology at the University of California, Giacomo Bernardi.
Professor Bernardi says the fish's use of the rock as its tool requires a lot of forward thinking, because there are a number of steps involved.