Friday, January 16, 2015

Because hyenas are great, and beautiful, and cute AND smart.

Let’s add a French touch to the hyena blog!!
I joined Kay’s lab last winter, for a two-year post-doc. My name is Agathe (in French, you would pronounce the A as you say it when the doctor is looking inside your mouth, and then pretend there is no H after the T, as it is usually silent in our beautiful language).
Ok, enough about French pronunciation. I’ve been in the Maasai Mara since last September, shame on me for not writing a blog post before, no excuse.

I’m an ethologist, meaning I’m studying behavior (of animals but also of human beings). My project here focuses on cognition, more specifically behavioral flexibility. Let me explain. 

   So, as you probably know, as primates, we are one of the species that can claim one of the biggest relative brain size among mammals. However, you would be surprised by what some birds can do, or even honeybees (Komischke et al, 2002). But, this depends on what kind of cognitive tests you are considering. In fact, cognition can be divided in two categories: physical and social cognition. While the first helps us deal with inanimate objects, we are able to understand our conspecifics intentional actions, perception and knowledge thanks to the latest (Herrmann et al, 2008). Of course, social cognition is most useful when living in a big society, which means frequent encounters with conspecifics. As a matter of fact, social complexity could be what drove individuals to have bigger and bigger brains by evolution (Byrne & Whitten, 1988). This is because living in a complex society enforced the need to understand its social rules, or to predict/understand the intentions of your conspecifics, especially if they’re higher ranking. As an example, when you are a middle ranking animal, you better be able to tell if that high ranking female approaching your kid is going to bite its head off, or just sniff it on her way and go. Or, before you come to rescue your BFF who’s being bullied, you want to make sure that his tormentor is not higher ranking, because he will remember you next time…

   You probably know by now how great our hyenas are, and like monkeys, they are able to recognize any member of their clan. Therefore they can remember their social status and choose to join someone in a brawl based on previous interactions and social affinity (Holekamp et al, 2007). Overall, they meet the criteria to fit in the social intelligence hypothesis.
   On the other hand, we know very little regarding their physical cognition (however, see previous work on our hyenas here), mostly because majority of that research focuses on primates. The social intelligence hypothesis predicts a high level of physical cognition along with social cognition. The key is to choose a task that can be done by several species, so that a wide comparison between species is possible. Let’s forget about IQ tests right away, only a chimpanzee would give the pen back when he’s done, and even a rather civilized baboon would eat it. Behavioral flexibility, the ability to adapt one’s behavior to solve a problem, is a good measure of general intelligence and can be adapted through various tasks.

   The hard part was to choose a task that hyena could solve without the use of hands, unlike their primate friends. Moreover, wild hyenas are very cautious toward man-made objects, hence I chose a task that they could do in several steps, to eliminate any bias of novelty on their ability to solve the task. So, to test their ability to display flexible behavior, I’m using a reversal learning test where the hyenas have to pull ropes to get access to meat, as a reward. They first have to learn to discriminate between two colors (black versus yellow), one associated with the reward, the other one associated with the absence of that reward. Once they have learned that, the rewarded and the non-rewarded colors are reversed and they have to suppress one behavior in favor of another to get the meat.

On this video: from the inside of the box: Decimeter, a subadult high-ranking female, comes and pulls the rope. It's her first time though, so she is kind of freaked out instead of taking the meat right away. 

  Conducting an experiment on wild hyenas takes time, especially when I have to find them across their wide territory and get them to interact with the device. After a very long habituation phase, I have now started the learning phase, trusting that my beloved subjects will learn it quickly (because I believe that they are indeed smart). Then, the best part begins: reversal learning!

Unlike Decimeter, KENG is used to the box and loves it. You can see  that she already got the meat on the right side. Here she is trying to pull the yellow rope, but the left tray is blocked : she now has to learn that only the black rope will get her meat! 

  Another time I’ll tell you how it went with lions (we could not find any hyenas that day, and I was curious…).

Byrne RW, Whiten A (1988): Machiavellian Intelligence..Oxford, Clarendon Press.
Jerison HJ (1973): Evolution of the Brain and Intelligence. London, Academic Press.
Hermann et al (2007): Humans have evolved specialized skills for social cognition: the cultural intelligence hypothesis. Science (317), 1360-1365.
Komischke et al (2002): Successive olfactory reversal earning in honeybees. Learning & Memory (9), 122–129
Holekamp et al (2007): Social intelligence in the spotted hyena (Crocuta crocuta). Phil. Trans. R. Soc. B (362), 523-538. 


Hadley said...

DECM is gorgeous, she's growing up so well :)

Lily J-U said...

Wow this awesome! Glad to hear the apparatus is built and working well!! Can't wait to hear about your results!! Great video too.

Nora said...

I love the post and video!! Hope to see some more French on the blog soon ;)

Heidi said...


Heidi said...
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Ignacious Gman said...

speaking of Hyenas and ropes, i remember (yet again) a documentary where scientists were testing group communication intelligence of some sort. and they set a board on the ground outside a metal cage with two ropes on each end. the board had several bowls of food in them near the center.

The board was presented in such a way that the hyenas had to work together to pull the ropes at the same time or the board would not move towards the cage in the right angle to gain them access to food. If they pulled on one end before the other the other end would sway out away from the cage and its rope would no longer be reachable from the cage. leaving the food in the middle of the board inaccessible as well.

Hyenas not only were faster at discovering the timing and teamwork required to successfully complete this task and get the food than chimpanzees. But they were also had a higher success rate in their attempts.

Michigan State University | College of Natural Science