Social bats:
A friend once told me she was saddened by the thought that wild animals were alone. They only got together to mate. The mother raised the offspring, and that was that. I suppose I notice social animals more, but my sense is that even the solitary ones are not truly alone. They know about each other, more or less keep track of each other and probably have some sort of interaction beyond what is needful purely for procreation.
But for social animals the interactions are intriguing. I sometimes take an hour’s stroll, and last year a crow decided to hassle me. Over some four blocks the crow would dive close to my head screaming, “Caw, caw!” I tried to act indifferent, but I did not relish the notion of the bird missing its plan by an inch or so and laying open my scalp. Then one afternoon I heard the usual caw and flapping and then there was a second rather louder caw and a second pair of wings flapping behind my head.
“Great,” thought I. “All I needed was a second one.” But when I looked around there was no second crow. A mockingbird had dived on the crow, imitated its voice and spoiled its game. And so the battle was joined, I taking my walk daily and the two birds doing battle over my scalp. The books say that a bird in a fight will begin with an all out attack, and if that does not work every further gesture is always bluff. My mockingbird friend laid out a sophisticated strategy. She would perch where an attack on me would leave the crow open to being blindsided. Sometimes they had it out in mid air. The mockingbird was not half the size of the crow but depended on much greater maneuverability. On a fair field she would have had no difficulty, but as it was she was looking out both for herself and for me. Sometimes I would come along the lane that led into the war zone and she would be perched on a branch waiting for me.
Once the baffled crow perched where it would have a nice steep dive on me as I walked past. The mockingbird perched not eight inches from the crow, confronting it. Her timing was exquisite. She remained just long enough for me – and I’m sure the crow – to decide, “All right. She’s just going to sit there.” Then she crashed straight into its chest.
In the end she not only drove out that crow. A different flock of crows, with a recognizable double caw, lives around my house. My crows expanded into the war zone and the entire flock that included my tormentor departed for parts unknown.
These are social birds, of course, but don’t try to tell me they do not know one individual from another.
Well it’s now official. It turns out that social bats also are able to recognize other bats and will have bats that are not their relatives that they will prefer to handg out with and that they will renew association with after long separation. (See You Next Summer, SCIENCE vol. 331 no. 6023 March 18, 2011 page 1366 reviewing Kerth et al. Proc. R. Soc. London Ser. 278, 10.1098/rsbp.2010.2718(2011)
Somehow animals are able to recognize kissing cousins sufficiently well to be able to survive. We will have to learn to do so. The question arises as to how and it looks as if, like other animals, we are simply going to have to work at it.
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