Saturday, December 21, 2013

Meet the beaver

My theory of animal cognition began many years ago when my wife and I were studying beaver. I was working my way through grad school by designing earth dams for the US Government. Beavers build earth dams so naturally I was interested.

What I discovered was that a beaver dam is very different from a human dam. In fact a beaver dam is more like a bird's nest. A human dam is a big pile of carefully selected and compacted dirt. A beaver dam is typically a lattice of sticks supporting an upstream face of dirt. One advantage of this design is that it uses a lot less dirt than a human dam does. Another is that it does not wash away when water flows over the top, as human dams tend to do.

Presumably the beaver knows how to build these elaborate structures by instinct. But what I realized while watching them work is that a great many decisions have to be made along the way. These decisions involve the specifics of the local situation, so they cannot be merely instinctive.

For example, knowing how to build a dam does not tell the beaver which stick to use next. Or which tree to fell and how to cut it up to get that stick. Or where to get the next armload of mud. Or where and how to put these items into the structure. These specifics cannot be in the DNA, as it were.

The point is that the beaver must have elaborate sets of concepts in order to perform these elaborate tasks. So do birds and so do horses. It is easiest to see this when we know what the critter is doing. Speaking of which it is an interesting question why beavers typically build many dams in one place, not just the one their lodge is behind. I think I have a surprising answer to this question but that will be another posting.

Saturday, December 7, 2013

Horses communicate a lot with posture and gesture

Unlike crows, horses do relatively little vocal communication. Of course they do sometimes whinny, nicker, snort, etc., but this is not the mainstay of their communication. As herd animals they are naturally in close contact, so they rely on what I call posture and gesture for communication.

For example, they make faces at each other, a lot of different faces, each with its own meaning. They frequently push one another, but without touching, by simply approaching in a certain way. They can threaten to kick by reversing, or mock strike with a front foot, or threaten to bite, etc. They can also groom one another, or play the face biting game, etc. Sometimes simply being close by is a form of friendship.

The point is that there is a huge amount of communication going on among the horses. This is easy to miss because humans tend to equate communication with human communication, which is dominated by verbal exchanges, just as with the crows. So-called body language is recognized to occur, but its role in human communication is relatively minor. With horses it is the primary means of communication, and there is a lot of it.