Prairie Dog Communication

istockphoto.comA recent NPR radio show covered the research of the biosemiotician Con Slobodchikoff of the Univeristy of Arizone on prairie dog calls. The piece is very public-orientated, but still might be worth listening to.

ResearchBlogging.orgWe’ve all (I hope) heard of the vervet monkeys, which have different alarm calls for different predators, such as for leopard (Panthera pardus), martial eagle (Polemaetus bellicosus), and python (Python sebae). (Seyfarth et al. 1980) For each of these predators, an inherent and unlearned call is uttered by the first spectator, after which the vervet  monkeys respond in a suitable manner – climb a tree, seek shelter, etc. It appears, however, that prairie dogs have a similar system, and that it is a bit more complicated.

Slobodchikoff conducted a study where three girls (probably underpaid, underprivaleged, and underappreciated (under)graduate students) walked through a prairie dog colony wearing shirts of the colors green, yellow, and blue. The call of the first prairie dog to notice them was recorded, after which the prairie dogs all fled into their burrows. The intern then walked through the entire colony, took a break for ten minutes, changed shirts, and did it again.

What is interesting is that the prairie dogs have significantly different calls (important, as they are pretty much exactly the same to human ears) for blue and yellow, but not for yellow and green. This is due to the dichromatic nature of praire dog eyesight (for a full study of the eyesight of retinal photoreceptors of subterranean rodents, consult Schleich et al. 2010). The distinction between blue and yellow is important, however, as there isn’t necessarily any reason that blue people are any more dangerous to praire dogs than yellow ones. “This in turn suggests that the prairie dogs are labeling the predators according to some cognitive category, rather than merely providing instructions on how to escape from a particular predator or responding to the urgency of a predator attack.” (Slobodchikoff 2009, pp. 438)

Another study was then done where two towers were built and a line was strung between them. When cut out shapes were slung down the line, the prairie dogs were able to distinguish a triangle from a circle, but not a circle from a square. So, the prairie dogs are not entirely perfect at encoding information. The conclusion still stands however that more information is encoded in the calls than is entirely relevant to a suitable reaction (unless one were to argue that evolutionary pressure existed on prairie dogs to distinguish blue predators from yellow ones.)

NPR labels this ‘prairiedogese’, which makes me shiver and reminds me of Punxatawney Pennsylvania, where Bill Murray was stuck on a vicious cycle in the movie Groundhog Day, forced every day to watch the mayor recite the translated proclamation of the Groundhog, which of course spoke in ‘groundhogese’. Luckily, however, there won’t be courses in this ‘language’.


Schleich, C., Vielma, A., Glösmann, M., Palacios, A., & Peichl, L. (2010). Retinal photoreceptors of two subterranean tuco-tuco species (Rodentia, Ctenomys): Morphology, topography, and spectral sensitivity The Journal of Comparative Neurology, 518 (19), 4001-4015 DOI: 10.1002/cne.22440

Seyfarth, R., Cheney, D., & Marler, P. (1980). Monkey responses to three different alarm calls: evidence of predator classification and semantic communication Science, 210 (4471), 801-803 DOI: 10.1126/science.7433999

Slobodchikoff CN, Paseka A, & Verdolin JL (2009). Prairie dog alarm calls encode labels about predator colors. Animal cognition, 12 (3), 435-9 PMID: 19116730

Under the Influence: An overview of recent insights into the CNTNAP2 gene

In my last post I outlined a number of experimental studies using the Zebra Finch that have highlighted an additional dimension to the FoxP2 gene – not only is it upregulated in the avian brain throughout song development, but it is also downregulated in important song nuclei of adult birds in singing contexts that seem to involve ‘listening to one’s own song’ and subsequent error correction.  Given that the pattern of expression of this gene is very similar in the developing brain of both humans and birds, one conclusion that has been drawn from this research is that FOXP2 downregulation may equivocally serve to facilitate online language processing function in the adult human brain.

General background on an intriguing new celebrity

Naturally, the next step has been to try and identify the downstream genes regulated by FOXP2 in order to build up a more detailed picture of how interactions between complex genetic networks influence key language-related disorders in humans.   It is as a result of such efforts that another gene, although discovered almost a decade ago, has found its way into the spotlight: CNTNAP2.

In the developing human brain, CNTNAP2 is enriched in functionally specialised regions such as the frontal cortex, the stratium, and the dorsal thalamus (circuits within these regions are referred to as cortico-striato-thalmic circuits) central to executive function, planning and executing complex sequential movements, and thus potentially, language.  This presents a striking contrast to the more uniform expression of Cntnap2 observed in the developing rodent brain where there is no evidence for enrichment in specific regions, suggesting a functional difference in the human version that could be related to vocal learning and modification.

Continue reading “Under the Influence: An overview of recent insights into the CNTNAP2 gene”