Dolphins Seen Using Shells to Catch FishBy: Brandon Klaus
Here’s an interesting story from Wired regarding tool use among dolphins. We all know just how intelligent dolphins can be, yet they still seem to amaze researchers with new hunting tactics and social behaviors. Already recognized as the first tool-using marine mammals, the bottlenose dolphins from Shark Bay, Australia have wowed experts again by using conch shells to trap fish, then shaking them into their mouths. According to researchers, this feeding behavior has been seen among female dolphins as early as 1996, with only a small handful of instances seen since then. But what got researchers really talking was the photographic proof, which was seen for the first time in 2007.
The photographing of this “conching” behavior occurred when a group of researchers spotted an unknown female dolphin swimming in the area they were conducting their research. The scientists attempted to grab a tissue sample from the dolphin, but before they could, it swam to the bottom and gabbed a conch shell. After surfacing, the researchers spotted the dolphin manipulating the shell to get to the fish hiding inside. Another interesting point was that only one male has been seen using this feeding strategy, indicating that females may share the behavior with other females within a pod.
Despite what the scientists have seen, there are still many unknowns as to the how and why this feeding behavior got started.
Exactly how the shells are used underwater isn’t yet known. Fish might swim into them while being chased, unwittingly turning themselves into packaged snacks. The dolphins could also use the shells like nets or containers, a possibility suggested by the wildlife observer’s report of seabed-digging.
Also unknown is how conching emerged: as a variation on sponging, perhaps, or in flashes of insight from creatures whose intelligence may rival our own but happen to lack fingers and hands. Because Shark Bay’s dolphins are very territorial, however, and conching has been witnessed in disparate locations on its east and west sides, the researchers believe conching was discovered several times independently.
The researchers also add that due to the difficulty of the behavior and how rarely it is seen it the wild, conching is a fairly new technique that requires a great deal of skill on the dolphin’s part. They also add though that it is becoming an increasingly popular strategy.
All images and story information taken from Wired.