Wednesday, February 1, 2012

Y'all tawk funny, doncha know

Within the last year, I have moved from Wisconsin to Texas and back to Wisconsin and no matter where I am people poke fun at my occasional word choices and pronunciations. For a girl who didn’t grow up in either state, it can be a lot to keep straight. In Texas, if I couldn’t fit my bucket under the water fountain to fill it, I would fill it at the spigot. But in Wisconsin, if my pail doesn’t fit under the bubbler, I fill it at the faucet. Usually, it’s not a problem, because I don’t often fill buckets or pails. But it has also affected my fashion-sense, because I can never remember if I have a “whaht bag” or a “white bague”… so now I just carry a black purse.

All of our struggles for dialectal conformity (admit it, even you have tried to talk like the cool kids at times) have come from the fact that we learn language through both vertical and horizontal transmission (and no, I’m not talking about the way STDs are spread). We learn language both from our parents (vertical transmission) and our peers (horizontal transmission). We now suspect that orcas (also called killer whales) do too.

Photo by Olga Filatova

Orcas live in matrilineal units consisting of a mother and her offspring. Related matrilineal units will travel together in larger groups, called pods. Although pods may come together for hunting, mating or other social interactions, each pod has a unique collection of call types (called a vocal repertoire or dialect). Some call types may be similar among some pods, and pods that share some call types are considered to be part of the same clan. Pods that do not share any call types are considered to be from different clans.

Orca individuals learn their pod’s dialect from their mothers. This in itself is pretty impressive: vocal learning is rare in mammals (exceptions being humans and some whales, dolphins, seals, and bats). The classical theory of orca dialects (yes, there is a classical theory of nearly everything) argues that dialects are transmitted only vertically (from mother to calf), and that changes in dialects between pods occur due to the accumulation of copying errors. Think of the game of “Telephone”, where one person whispers a message, such as “I like vanilla ice cream with caramel on top”, which is then whispered to the next person and then the next person, until the message received by the person at the end of the line is something like, “Ike the gorilla had a nice dream about Carrot Top". A collaborative research team from Russia and the UK are now challenging that idea with evidence suggesting that adult orcas also learn from other adult orcas.

This research team, including Olga Filatova at Moscow State University, Alexander Burdin at the Pacific Institute of Geography, and Erich Hoyt at the Whale and Dolphin Conservation Society, determined which call types were included in the repertoires of 11 orca pods that were all members of the same clan. Then for each call type, they compared how similar the calls were across all pods that produced it. This data doesn’t come easy: they recorded orca calls off the Kamchatka Peninsula from an inflatable motor boat with an outboard motor for the better part of a decade. After analyzing all of the recordings, they discovered that different call types can vary in their degree of similarity across pods, suggesting different patterns and rates of change from pod to pod. If differences in pod dialects come about only due to copying errors when calves are learning from Mom, we would expect more consistent rates and patterns of change of calls across pods. One possible explanation is that when pods come into contact with one another and socially interact, adult orcas learn new call types (like we learn new words) and/or adjust features of call types (like we change our pronunciation of a word) from individuals in other pods. So the next time you find yourself far from home and talkin’ a little differ’nt, at least you’ll know you ain’t the only one.

Here are two orca recordings from two different clans (Kaplya pod and Avacha clan). Personally, I think they both sound like clowns making animal balloons. But if you can tell the difference, maybe you have a future in animal behavior research… or maybe you’re the next Dr. Doolittle.

Wanna know if you talk funny? Take this test.

Want to know more? Check these out:
1. Filatova, O.A., Burdin, A.M., Hoyt, E. (2010). Horizontal transmission of vocal traditions in killer whale (Orcinus orca) dialects. Biology Bulletin, 37(9), 965-971.
2. Ivkovich, T., Filatova, O.A., Burdin, A.M., Sato, H., Hoyt, E. (2010). The social organization of resident-type killer whales (Orcinus orca) in Avacha Gulf, Northwest Pacific, as revealed through association patterns and acoustic similarity. Mammalian Biology, 75(3), 198-210.
3. Deecke, V.B., Ford, J.K.B., Spong, P. (2000). Dialect change in resident killer whales: implications for vocal learning and cultural transmission. Animal Behaviour. 60. 629-638.
4. The Russian Orcas Homepage

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