Skip to main content

10.02.2023: Goffin’s cockatoos were shown to mentally represent the need of more than one tool at foraging site. Thereby they actively transport sets of two different tools together to the problem at hand.

Some problems cannot be solved with one single tool. Nevertheless, sometimes more than one different tool with different functions is needed (one after another) to reach a common goal. Tool sets represent an important part of human technology, and constitute one of the most advanced examples of animal technology.

Remarkably, reports of tool sets in the wild are limited to only two species, chimpanzees and Goffin’s cockatoos. While this skill was, until very recently, believed to be limited to our very closest living relatives, we recently learned that a species extremely distantly related to us, the Goffin's cockatoo, can also innovate the use of a tool set, at least in the wild. Nevertheless, being able to use a tool set and being able to mentally represent a tool set may be two very different things. For example, wild chimpanzees have been reported to use sturdy pounding tools to open termite mounds and thereafter use flimsy fishing tools to probe for termites. For quite some time it was argued that picking up the first tool may simply be triggered by seeing the mound blocked and that the use of the second tool is only triggered by seeing the now opened mound. So, what looked like a tool set, could have been nothing more than a chain of single tool uses on a representative level.

This view only changed after chimpanzees of the remote Goualougo Triangle (in the Congo basin) were observed transporting both tools simultaneously to the termite fishing sites. Therefore, these chimpanzees recognize the need of both tools before using any of them, suggesting the categorization of both tools as a set. Inspired by the Goualougo Triangle chimps, Antonio Osuna-Mascaró from the Messerli Research Institute at the University of Veterinary Medicine Vienna designed three experiments to test if Goffin’s cockatoos have the capability to mentally represent a genuine tool set.

Antonio Osuna-Mascaró describes the experiments of the study:

“First we wanted to test if these little cockatoos were able to innovate the use of a tool set by themselves”, says Osuna-Mascaró. “So, we presented to them a problem that resembles what is required for chimpanzee termite fishing: a membrane blocking access to a piece of nut, and two tools, a short pointy stick and a long flexible one. The membrane could only be ripped by using the pointy tool, but this was too short to reach the reward, so they would need to use both in sequence.” And he adds, “It’s funny, but the preferred food of these Goffin’s is the cashew nut, and its flavor is very similar to the flavor of the termites that chimpanzees eat. So, the similarities go beyond what we can visually perceive!”.

To the researcher's surprise, the cockatoos solved this first experiment with stunning ease. “We are used to Figaro being able to solve the tests masterfully, but I certainly didn't expect such speed” says Osuna-Mascaró. Figaro, the highest ranked male in the group, solved the task on his first opportunity in only 31 seconds (there were 10 minutes set for that trial). Fini, a female, did the same, she solved it in only 34 seconds. Other cockatoos needed two or three attempts to find the solution, but their performance can also be considered remarkable. Goffin’s were able to innovate the use of a tool set but, was this was just the result of a learned sequence of actions or did they have a mental representation of the two tools as a set? To solve this, the researchers added a second experiment. “To test if their tool set use was flexible, we alternated randomly between two boxes: one with a membrane, as before, and another with no barriers to reach the nut. So, the cockatoos had to act according to the problem, sometimes the tool set was needed, and sometimes only one tool was enough” says Osuna-Mascaró. This is reminiscent of what chimpanzees encounter when fishing termites in the Goualougo Triangle. Sometimes they need the full tool set, but on occasions the termite mound has unrepaired holes made by other chimpanzees. In those cases, only the fishing probe is enough.

As may be expected, the Austrian housed cockatoos excelled during this task too. But the researchers found something unexpected. Alice Auersperg, head of the Goffin Lab, explains it: “Before inserting the first tool, the animals tended to switch back and forth between picking up the two different options”, Auersperg explains. “Interestingly, their performance improved after performing this switching action; the probability of selecting the correct tool was higher after repetitive switches. In future experiments we hope to explore their decision-making process and perhaps certain aspects of their metacognition (their knowledge about their own knowledge)”.

After observing how cockatoos were able to innovate a solution to a problem by flexibly using a tool set, the Goffin Lab researchers wanted to test whether cockatoos would transport the two tools simultaneously as a set. A flexible transport (transporting both tools when needed), as the one performed by the Goualougo Triangle’s chimpanzees, would mean that the cockatoos understand the need of both tools before using them, and therefore can categorize both tools as a set. First, the cockatoos had to climb a ladder to reach an elevated platform were one of those two boxes (with or without membrane) were waiting. After this the same platform could only be reached by a brief horizontal flight, and finally a vertical (high-effort) flight.

“Four cockatoos eventually transported both tools together to the platform, even when it required a flying transport. It was very remarkable”, Osuna-Mascaró says. “Three of those cockatoos transported the tools together in a very consistent fashion. Once they learned to transport (by themselves), they transported both tools together every single time that they encountered the box that required them, and less frequently to the box that didn’t”. Apart from our own species, only two others are known to use tool sets in the wild, and the present study shows that the tool set use of both, chimpanzees and Goffin’s cockatoos, is more than simply using one tool and then another. “Our cockatoos, did always have the opportunity to go back and forth, using one tool and then go back to pick up, transport and use the other. Instead, at least three of them learned to collect both tools in advance. This suggests that they can categorize both tools as a set” Osuna-Mascaró explains. Alice Auersperg adds: “For understanding the emergence our own technical abilities, it is necessary to not only look at our most closed living relatives, but additionally at how similar capacities arise in species that are extremely distantly related to us (in this case separated by more than 300 million years of evolution)”.

Further information:

Antonio J. Osuna-Mascaró, Mark O'Hara, Remco Folkertsma, Sabine Tebbich, Sarah R. Beck, Alice M.I. Auersperg: "Flexible tool set transport in Goffin’s cockatoos". Current Biology, 2023.*

Scientific article

Goffin Lab webpage

*The study is part of a collaborative project funded by the WWTF (Wiener Wissenschafts und Technologie Fund) and by the FWF (Austrian Science Fund). The researchers study the innovative skills of the cockatoos at the University of Veterinary Medicine Vienna and compare them with those of children of different ages (University of Birmingham).