Xenophobia is neither the fear of Xeni, nor of Xena. Rather, it's more about knee-jerk mistrust, dislike, and hatred for people who aren't part of your group. We've come to associate it with not liking people from other countries, but it applies to smaller-scale, less formal tribalism, as well.
Over at the Scientific American blogs, science writer and biologist Rob Dunn talks about some of the theories for why something as seemingly antisocial as xenophobia could have been beneficial to our ancestors—at least under certain circumstances. The key, he says, might be disease. Not cooperating between groups, refusing to share resources, and generally going out of your way to avoid strangers makes sense if those strangers are infected with something that could kill you.
If I'm understanding Dunn correctly, the research and theorizing on this topic isn't saying xenophobia is good. Nor is it saying that all xenophobia grows out of a conscious, reasonable fear of disease. It's more like, the times when xenophobia did turn out to be coincidentally beneficial happened to reward people who were more likely to pass on xenophobic tendencies to their offspring (whether those tendencies were genetic or cultural is hard to say). Thus, the tendency continues, even in situations where it's actively detrimental. And Dunn points to an interesting recent study that showed deadly white-nose syndrome is causing xenophobic-esque changes in the behavior of bat populations.
Although it looked as though the little brown bats and several other species might soon face extinction, at least in some regions and perhaps even in North America, the little brown bats have begun to rebound in some places, albeit modestly. A new paper out this week takes notice of one of the reasons they appear to be rebounding, the bats are avoiding each other. Little brown bats (at least historically) tend to roost in large, groups, one next to the other, bumping fuzzies as it were. But not anymore. More and more, this new study, led by Kate Langwig, a graduate student at Boston University, suggests, the bats are spreading themselves out in their roosting caves, their hibernacula. Once, they clumped, warming themselves around the tiny fires of their bodies. Now, they go it alone.
Langwig's results are preliminary, as she and her colleagues are the first to admit. She has measured the change in the bat roosting (and abundance) before and after the arrival of the disease, but she has not really studied the behavior of the bats and how it is they come to be spaced apart. Yet, the bats the are important from the perspective of the basic biology and conservation of the bats and so there remains much to do and much that can be done. For example, it would be good to know if the probability of transmission of the disease really goes down when the bats are further apart. It would also be interesting to figure out if the same individuals that were once nuzzling up next to each other, are now hanging out on their own.