Adaptive Explanations
Abednego over at Parableman highlights an article about bat hunting behaviour

bats track insects they want to catch in a way that is very different from that of humans and some other animals. Essentially, humans, fish, dogs, and others use a strategy the article calls "constant bearing" to follow things -- basically, they just head straight for their target. Bats, on the other hand, actually take into account the target's velocity and direction and flies partially parallel to the target. In other words, bats work out in advance where they think their targets will be, and head there, rather than directly towards the target, which saves time.

Abednego finds the evolutionary explanation is not much of an explanation.

Evolution is invoked as an explanation of why bats fly this way -- they need to catch their prey as quickly as possible. Does that mean that humans and other animals don't need to catch their prey as quickly as possible? It really seems like a useless remark to me.

Essentially what Abednego has stumbled upon is that evolution is useless for predicting things. This is why there are many researchers who don't think the theory of evolution is important for their research. Just as in this article it was not whether the bat evolved or not, but instead how they hunted that was the issue.

Jeremy Pierce also comments

It's an explanation of how the trait would survive if it could occur, without actually saying anything about what brought it about in the first place. I think that does count as a sort of explanation, but I think you're right that they're misstating what the explanation is, and they're misstating how much it's actually explaining.

This is what is known as a Just-so story. It isn't a scientific explanation, as much as an untestable ad hoc explanation. You can modify the situation all you want, and they just adapt their explanation to suit it.
- posted by Alan Grey @ Friday, May 12, 2006