Dolphins in the News
There’s a relatively recent story about tool use in dolphins, pointing to the use of sponges for protecting the rostrum in dolphins of Shark Bay, Australia.
The story relates how the researchers utilized genetic data to determine that this behavior is passed on from mother to offspring. So far, so good. Then they make the claim that this is the first evidence of a culturally transmitted behavior in a marine mammal.
This is the first time scientists have found evidence for the passing on of cultural behaviour in marine mammals.
Hmmm. My baloney detector is making “wheep-wheep!” noises over this claim.
It might be the first study of transmitted cultural behavior with genetic assays backing it up, but that’s not the only form of evidence available for establishing a culturally transmitted behavior. I heard a talk a few years ago concerning observation of a human-dolphin cooperative fishery in South America, where the dolphins participating in the fishery learned the behavior from mom. I’ll see if I can look that up. As for cooperative human-dolphin fisheries, reports of those go back to Pliny. A more modern report was made by Rene-Guy Busnel (1973. “Symbiotic relationship between man and dolphins.” Transactions of the New York Academy of Sciences, Series 11, 35(2):112-131.). Do we really think that multi-generational cooperative fisheries do not involve cultural transmission of the behavior on the part of the dolphins?
We scientists do like to put claims of “first” in our findings. Unfortunately, we don’t always do the hard work of checking to make sure that it really is a “first” and not a “second”, “third”, or “thousandth”. This research with the sponge behavior is interesting on its own account, and the likely-overblown claim of novelty is just an annoying distraction.
I think the South American fishery you mention here is at Laguna, Santa Catarina, Brazil. Generations of dolphin have cooperated with local fishermen to catch mullet. They drive the fish towards the humans, then signal when it’s time to cast the throw nets. The activity is initiated by the dolphin, and the skills required seem to be passed down mainly through the females (which stick closer to mum for longer, and so have time to learn them).
Thanks for the information, Malcolm! With that and Google Scholar, I turned up the following:
Documentary made about just this in Laguna:
‘Les dauphins cueilleurs de vie’ by F.X. Pelletier.