The more we learn about other animals the more fascinating they are
A few months ago I wrote an essay about crafty crocodiles who use a tool lure prey. While some questioned whether it really was tool use, Dr. Benjamin Beck, the world’s authority on tool behavior in nonhuman animals (animals), said it was.
Crafty cod
Now, we’ve just learned that Atlantic cod also learn how to use a tool to get food. The abstract for the original article written by Dr. Sandie Millot and her colleagues and published in the journal Animal Cognition called “Innovative behaviour in fish: Atlantic cod can learn to use an external tag to manipulate a self-feeder” reads as follows.
This study describes how three individual fish, Atlantic cod (Gadus morhua L.), developed a novel behaviour and learnt to use a dorsally attached external tag to activate a self-feeder. This behaviour was repeated up to several hundred times, and over time these fish fine-tuned the behaviour and made a series of goal-directed coordinated movements needed to attach the feeder’s pull string to the tag and stretch the string until the feeder was activated. These observations demonstrate a capacity in cod to develop a novel behaviour utilizing an attached tag as a tool to achieve a goal. This may be seen as one of the very few observed examples of innovation and tool use in fish.
To summarize briefly, Dr. Millot and her research team made a feeding machine that fish could operate using a pull string. They learned to swim up to it, pull the string, and get food. Each fish was also fitted with a small tag with a colored bead so that the researchers could reliably identify individuals. And, what happened was very surprising because three fish learned “they could use the artificial tags, rather than their mouths, to operate the feeder. They learned to swim past the string and hook it onto their tags so that the food would be released that way. For each of the fish, the moment of insight began by accident. The fish appeared to accidentally catch their tags on the feeder’s pull-string. As soon as they felt the pull of the string, they showed what’s called a startle reaction: they immediately responded with a fast burst of swimming until the tag became unhooked. Eventually, after a bit of trial and error and fine-tuning, all three fish were performing the action with apparent intention, using their dorsal tags alone rather than their mouths to operate the feeder.”
The sequence of behavior is shown below and you can watch it here.
This is a very valuable experiment because it shows that tool behavior is not limited to big-brained mammals or brainy birds. In their outstanding and comprehensive book book called Animal Tool Behavior, Robert Shumaker, Kristina Walkup, and Benjamin Beck list other examples of tool use by fish. They also highlight other “surprises” in species in which tool behavior would not have been expected.
It’s clear that fish aren’t merely streams of protein for our and other animals’ consumption, and we should respect them for who they are, smart and sentient beings who feel pain and care about what happens to them (see also). In her seminal book called Do Fish Feel Pain? renowned researcher Dr. Victoria Braithwaite concluded, “I have argued that there is as much evidence that fish feel pain and suffer as there is for birds and mammals — and more than there is for human neonates and preterm babies.” (page 153). This is a wise lesson that shows that speciesist thinking that results in animals being ranked as “higher” and “lower” on a human-constructed linear scale doesn’t work.
Stay tuned for more on the cognitive and emotional worlds of the fascinating animals with whom we share our planet. It’s best to keep an open mind about what they are able to do, to learn, and what they feel.
Marc Bekoff’s latest books are Jasper’s story: Saving moon bears (with Jill Robinson; see also), Ignoring nature no more: The case for compassionate conservation (see also), and Why dogs hump and bees get depressed (see also). Rewilding our hearts: Building pathways of compassion and coexistence will be published fall 2014. (marcbekoff.com; @MarcBekoff)
Note: I was just reminded of a very this very interesting paper:
Kuba, M., Bryne, R., & Burghardt, G. M. Introducing a new method to study problem solving and tool use in fresh water stingrays, Potamotrygon castexi. Animal Cognition, 2010, 13, 507-513.
See also Culum Brown’s excellent paper called “Tool use in fishes
Exposing the Big Game 