Fans of the Wind in the WIllows have long known that otters are gregarious, friendly beasts. And now, researchers agree: a study of Giant Otters in the wild in Peru and in zoos in Germany revealed that they have big vocabularies, with 22 distinct types of vocalizations. This species of otter is also the largest, reaching a massive 5 feet in length.
The researchers, led by Christina Mumm and Mirjam Knorschild, hypothesize that vocal complexity is correlated with social complexity; this has been proposed for other species as well, whereby increasingly complex social structures bring about complex vocalizations. This has some interesting implications for the origins of human language; perhaps larger, more complicated social groups developed to help with clan defense or nutrient acquisition, and the resulting complex social order required nuanced language. Language development, in turn, is widely viewed as being critical in the development of extreme intelligence in humans.
Another study experimentally tested the "social complexity leads to vocal complexity" hypothesis in chickadees, finding that indeed,
1) naturally larger groups in the wild used more complex calls, and
2) aviary groups made artificially larger used more complex calls.
This is compelling evidence that social complexity requires- and generates!- vocal complexity. Read the original study here.
“It'll be all right, my fine fellow," said the Otter. "I'm coming along with you, and I know every path blindfold; and if there's a head that needs to be punched, you can confidently rely upon me to punch it.”
After analyzing the data, the researchers found vocal capacity among the adult otters for 22 distinct vocalization types and 11 vocalization types used distinctly by the babbling newborns. For example, what the researchers termed a "whistle" would occasionally be made across short ranges when calling group members, or when begging. "Growls" indicated threatening or warning, defending a fish, or playing. "Contact calls," meanwhile, were used when calling group members, swimming or fishing together, moving on land together, or playing or begging.