Monday, December 22, 2014

Grazing data. Easy to see but hard to get.

Grazing by horses is a good example of the challenge of getting good data to do research on. Getting good data is often the difficult and expensive part of doing research and grazing is no exception.

As we have discussed, our small observation herd of horses grazes in a way that is both active and mysterious. They are seldom in the same location for very long (but sometimes they are). The research question is "what rules explain this complex grazing behavior?"

In order to answer this question (if we can) we will need good data on where the horses graze over time, because that is what we are trying to explain. We probably need at least several months of data. This data sounds simple enough but getting it will not be easy. It is one thing to see that the horses are typically moving around a lot, but quite another to track just where they go and when.

Here are some possibilities, ranked by the quality (and cost) of the resulting data.

1. Attach a GPS transmitter to each horse. Each transmitter sends the horses location to a central receiving station, either in real time or periodically.

2. Attach a GPS recorder to each horse, which is then read manually from time to time to get the data.

3. Contract for satellite photos of the fields to be taken at (hopefully regular) intervals. Does not work at night or when cloudy.

4. Set up automated cameras at various locations to take repeated pictures of the fields. The location of the horses at each time can then be calculated manually using triangulation. Laborious and does not work at night.

5. Monitor one or more specific locations, such as with an automated camera taking periodic pictures. Incomplete data.

6. Manually estimate and note where the horses are, from time to time. Laborious and incomplete.

There are other data collection strategies, I am sure, and I would be happy to hear about them.

In short there is no easy and cheap way to get good data, even though the behavior is right there in front of us. This challenge is a big part of what makes good science difficult and expensive to do.

Friday, December 5, 2014

Swarming horses

I have written before about the fascinating and mysterious behavior that horses exhibit when grazing together. The individual horses are frequently close together, but not always. They clearly choose collectively where to graze, which is highly variable and unpredictable, but how?

The relatively new artificial intelligence field called "swarm intelligence" may be useful here.
See for an introduction.

Swarming in this case is a technical term. It refers to complex collective behavior governed by relatively simple rules operating at the individual level. Work in this area goes by other names as well, such as flocking. See

The research question then arises whether these two collective grazing behaviors of horses, staying together and moving around, can be explained using swarm or flocking rules?

For example, it has been suggested that the way deer move around from day to day is deliberately random, in order to deter predation based on predictable behavior. Where horses graze, from hour to hour and day to day, is certainly complex, but is it random or due to some combination of simple rules?

Mind you we may not have to actually build swarming horse robots. Computer simulation may be enough. We will of course also need specific data describing these behaviors in detail. Thus the research is not simple. But the results might be useful in both horse and land management, as well as for grazing critters besides horses, such as cattle, sheep and deer.