Who’s the cleverest in the land: let the battle begin!
So this time I have two articles to talk about. Hope it makes up for the lack of post last week. I was a bad girl, I know.
First up are the bird brains. The following article pits New Caledonian crows (love corvids!) against keas (parrots are ok too, I guess). They are given the same task, which is basically a puzzle with four different solutions and food as reward.
Auersperg AMI, von Bayern AMP, Gajdon GK, Huber L, Kacelnik A (2011) Flexibility in Problem Solving and Tool Use of Kea and New Caledonian Crows in a Multi Access Box Paradigm. PLoS ONE 6(6): e20231. doi:10.1371/journal.pone.0020231
Both keas and New Caledonian crows are renowned for their intelligence and they didn’t fail to impress me this time either. The four ways to get at the food in these trials consisted of two types of tool use (a stick or a ball) and two methods of non-tool use (pulling a string and opening a window). The birds were presented with a box with food inside that they could reach through one of the methods I mentioned and observed. Once the birds had learned to get the food in a certain way, that was no longer allowed, so they had to do it in a different way and so on until the birds had discovered all the ways of reaching the food or until the researchers gave up.
I’m a bit disappointed by how badly the crows performed in this one. The keas thoroughly kicked their asses by learning 2-3 three of the methods in the first trial with not even all the crows learning one method and none of them more than one. There were some differences in which tasks were more easily learned by the two species. The crows were better with sticks than the keas (this is to be expected as the crows are experts with sticks) and the keas were better with the window and the ball. Both birds did really well with the string.
Overall, the keas learned all the methods faster than the crows and basically ruled. So why might this be? The authors think it’s due to neophobia/neophilia (fear or love of new things) and I agree. Keas are lucky enough to originate in a place where they have few natural predators (in fact, they sometimes *are* the predator) and as a result they are a bit like dodos. They don’t really feel fearful and are happy to explore new things. The crows however, are more fearful and take longer before they approach something new. One of the crows was excluded from this study because it completely failed to approach the box with food in it. The keas were much more explorative biting on everything and investigating orally (yeah, we all know that parrots like to chew on everything). The crows were more likely to stand back and investigate through observation. This of course makes it more likely that the keas discovered solutions by chance or even just through sheer perseverance. However, both crows and keas managed to solve all the problems one of which was highly unnatural for a kea to solve (stick problem) because of the shape of their beaks. So can’t really say the keas were dumb and lucky. They were clever and unafraid where the crows were clever and afraid. I’d like to see how the crows would do minus neophobia.
I should point out that none of the kea were wild caught, where some of the crows were. The best performing birds of both species were hand reared. Also, the sample sizes were small with 6 keas and 5 crows (one of which was excluded). I think that the different rearing and housing conditions of the birds will have contributed significantly to their performance and I also think it’s difficult to conclude much with such small sample sizes. Having said that, the difference in speed to solve tasks between the birds was massive and undeniable. However, if neophobia is the main cause of this, it doesn’t really say much about intelligence or cognitive/learning abilities. I would really love to become involved with this research. (What do you say, Kacelnik? Can I come and join your group for my postdoc? Pretty please? *angelface*)
Now the next study takes us a bit closer to home pitting gorillas against chimpanzees, chimpanzees against orangutans and finally human children against the non-human apes:
Hanus D, Mendes N, Tennie C, Call J (2011) Comparing the Performances of Apes (Gorilla gorilla, Pan troglodytes, Pongo pygmaeus) and Human Children (Homo sapiens) in the Floating Peanut Task. PLoS ONE 6(6): e19555. doi:10.1371/journal.pone.0019555
I won’t go on too long about this study, because this is already a very long post. They gave orangutans, chimpanzees, gorillas and children a relatively simple task, which was to retrieve a peanut from inside a vertical tube. The only way to get the peanut, was to put water into the tube until the peanut floated high enough to be reached. The children were provided with a jug of water where the other apes had a water dispenser. I think this gave the children an unfair advantage. Regardless, all of the different species of great apes managed to get the peanut, but the success rate wasn’t very high. Children did better, especially the 8 year olds of which over half figured out the solution. In human children, it helped to have the peanut already floating in the tube with the child only having to add some more water to reach the peanut. In non-human apes, this seemed to not make a difference at all. However, as the authors say, this may well be due to a small sample size. Personally, I think it was a bit unfair to expect the apes to complete this task with taking mouthfuls of water and spitting them into the tube. I think some sort of pool of water and a mobile container (jug or bucket) would have been better although this imposes the use of tools, which may be unfair when all you want is to get the animals to get the solution in the simplest way possible (although actually, no. It doesn’t impose tool us. It just adds it as an extra option. Taking mouthfuls of water would still be possible). Maybe a watering hose would have worked, but I can imagine the researchers getting quite wet. Anyway. The children came out as winners, but I think they had an unfair advantage.
In other news, there was a study on houbara migration in PLoS ONE, that I’ve chosen not to blog about because I have a feeling it is only interesting to people, who have worked with houbara. It’s about Macqueen’s bustards, that is Asian or Chlamydotis macqueeniii. They’re much more exciting than the African houbara 😉
- Clever tool use in parrots and crows (eurekalert.org)
- New study of crows and parrots highlights different types of intelligence (physorg.com)
- Crows and parrots – brainy birds, but in different ways | Not Exactly Rocket Science (blogs.discovermagazine.com)