Urbanization, neophobia, and problem solving

So, if you’ve been keeping up with the blog you’ve probably read a few posts about my cognition apparatuses and seen plenty of photos. Link here and here. If you haven’t read them, I’ll summarize briefly. I’m a graduate student on the Hyena Project and I’m testing the cognitive abilities of hyenas with a general problem solving task. I’m interested in the individual, social, and ecological factors that affect how good they are at learning to solve novel problems.

Studying cognition in the wild poses unique challenges…

I’ve been out here for four months now- so what’s happening with the hyenas? So far, I’ve mostly been conducting familiarization trials with the hyenas to help the hyenas learn to associate food with the puzzle box. In familiarization trials I leave the puzzle box wide open with food easily accessible (no problem solving required to open). This is to overcome any neophobia (fear of novelty or new things) a hyena might have and to increase their motivation to participate in cognition trials. There is a lot of increasing interest in testing the cognition of wild animals, since animals in captivity grow up in an unnatural environment. However, in the wild the results of a cognition study can be skewed based on which individuals decide to participate in trials. I put out the puzzle box within eyesight of a hyena and then the hyena decides whether or not to investigate the puzzle box or walk away. This can definitely skew results if hyenas with specific characteristics are more likely than others to participate. But, studying wild hyenas gives me the chance to assess how urbanization might affect learning in the wild.

A hyena watches a herd of cattle (credit hyaenidae.org).

How does urbanization affect animal cognition?

I’m collecting data in two different parts of the Maasai Mara National Reserve: Serena and Talek. In Talek, hyenas live on the border of the reserve and regularly encounter Maasai villagers, heavy and poorly regulated tourism, cattle grazing, and snares from poachers. In other words, they experience a high degree of “urbanization”. In Serena, hyenas are well protected from poaching and cattle grazing and tourism is strictly regulated. There’s a lot of interest in the scientific community on how the dramatically changed urbanized environments affects animals, and in particular, animal cognition. A large body of research suggests that rapidly changing environments, like urbanized ones, select for bigger brains and greater smarts (Marino 2005). Some studies have shown that urban animals have larger brains than rural animals (Maklakov et al. 2011; Snell-Rood & Wick 2013) and that large brained animals are better at invading new habitats (Amiel et al. 2011; Sol et al. 2008; Sol et al. 2005). However, in the short run changing environments can be highly stressful for animals and many species are unable to cope with change, resulting in extinction. In addition, large brained animals are also more like to be endangered (Abelson 2016).  

Some hyenas investigate the box, but even more of them hang out at a distance without ever touching it. 

Talek hyenas are more neophobic?

So far, it looks like Talek hyenas might be more neophobic than Serena hyenas because they’re less likely to eat the bait from inside the box. I’ve collected 149 trials with 63 different hyenas in Talek and 176 trials with 69 different hyenas in Serena. Out of these trials in just 28% trials a hyena fed from the puzzle box in Talek while in 38% of trials in Serena a hyena fed from the puzzle box. These were all familiarization trials (no problem solving required) where the box was left wide open with the food easily accessible. All the hyena has to do is walk up to the box, stick their head inside and eat the food. Whether or not a hyena is willing to eat food from a novel source could indicate their level of neophobia (though it could also indicate their food motivation level). Since a greater percentage of Serena hyenas were willing to feed from the puzzle box this could suggest that hyenas in Talek are more neophobic (more nervous about the puzzle box). However, it’s important to note that these are raw percentages and I have not controlled for the fact that some hyenas have gotten more than one trial with the box.

Neophobia and urbanization

Other studies have also found that urban animals are more neophobic than rural animals in addition to being better problem solvers (Griffin et al. 2015; Miranda et al. 2013; Audet et al. 2016).  However, other studies show that animals in novel or urban environments are less neophobic (Martin & Fitzgerald 2005; Møller 2009). While neophobia may help individuals to avoid dangers in a novel environment, it may also make them less likely to find novel sources of food to exploit.

VENI, an immigrant male hyena in Serena was fairly nervous about approaching the box.

Neophobia and problem solving

The relationship between neophobia and problem solving in animals is mostly inconclusive (Griffin & Guez 2014) but previous research with hyenas by hyena lab alumni Sarah Benson-Amram suggests that neophobic hyenas are less likely to successfully problem solve (Benson-Amram et al. 2013; Benson-Amram & Holekamp 2012).  If Talek hyenas really are more neophobic then they might be less likely to solve my puzzle box - if neophobia is a causal factor in performance and not just correlative. My hypothesis is that Talek hyenas will be better problem solvers, but neophobia could superficially make them worse. I.e. Talek hyenas could  be better problem solvers than Serena hyenas in reality, but neophobia could prevent them from interacting with the box making them look worse on paper. Therefore, I have to make sure to get as many familiarization trials to both Talek and Serena hyenas as possible to try and overcome any effect of neophobia so that I can test the effect of urbanization independently. Hopefully Talek and Serena hyenas will start getting test trials soon where they have to learn how to open the box to retrieve the bait inside. Who knows what I’ll find out!

References cited

Abelson, E.S., 2016. Brain size is correlated with endangerment status in mammals. Proceedings. Biological sciences / The Royal Society, 283(1825), p.20152772-.

Amiel, J.J., Tingley, R. & Shine, R., 2011. Smart moves: effects of relative brain size on establishment success of invasive amphibians and reptiles. PloS one, 6(4), p.e18277.

Audet, J.-N., Ducatez, S. & Lefebvre, L., 2016. The town bird and the country bird: problem solving and immunocompetence vary with urbanization. Behavioral Ecology, 27(2), pp.637–644.

Benson-Amram, S. & Holekamp, K.E., 2012. Innovative problem solving by wild spotted hyenas. Proceedings. Biological sciences / The Royal Society, 279(1744), pp.4087–95.

Benson-Amram, S., Weldele, M.L. & Holekamp, K.E., 2013. A comparison of innovative problem-solving abilities between wild and captive spotted hyaenas, Crocuta crocuta. Animal Behaviour, 85(2), pp.349–356.

Griffin, A.S. & Guez, D., 2014. Innovation and problem solving: a review of common mechanisms. Behav Processes, 109(Pt B), pp.121–134.

Griffin, A.S., Guillette, L.M. & Healy, S.D., 2015. Cognition and personality: an analysis of an emerging field. Trends in ecology & evolution, 30(4), pp.207–14.

Maklakov, A.A. et al., 2011. Brains and the city: big-brained passerine birds succeed in urban environments. Biology letters, 7(5), pp.730–2.

Marino, L., 2005. Big brains do matter in new environments. Proceedings of the National Academy of Sciences of the United States of America, 102(15), pp.5306–7.

Martin, L.B. & Fitzgerald, L., 2005. A taste for novelty in invading house sparrows, Passer domesticus. Behavioral Ecology, 16(4), pp.702–707.

Miranda, A.C. et al., 2013. Urbanization and its effects on personality traits: a result of microevolution or phenotypic plasticity? Global change biology, 19(9), pp.2634–44.

Møller, A.P., 2009. Successful city dwellers: a comparative study of the ecological characteristics of urban birds in the Western Palearctic. Oecologia, 159(4), pp.849–858.

Snell-Rood, E.C. & Wick, N., 2013. Anthropogenic environments exert variable selection on cranial capacity in mammals. Proceedings. Biological sciences / The Royal Society, 280(1769), p.20131384.

Sol, D. et al., 2005. Big brains, enhanced cognition, and response of birds to novel environments. Proceedings of the National Academy of Sciences of the United States of America, 102(15), pp.5460–5.

Sol, D. et al., 2008. Brain size predicts the success of mammal species introduced into novel environments. The American naturalist, 172 Suppl, pp.S63-71.