Our latest paper reports on two experiments, the first conducted by former undergraduate Vi Girbino and the second by former postdoc Simon Ripperger. Both experiments asked the same question: Can we predict social bond formation in vampire bats from the way two bats interact at their first encounter?
The reason we care about this question is that it tells us something about the role of social history in relationship formation. When we use the word “social relationship” we are basically assuming that two animals (1) recognize each other, (2) remember something from their history of social interactions, and (3) use those memories to form predictions about future interactions.
But if we are wrong? What if social relationships are actually reducible to immediately observable traits like size or scent? For example, two animals can decide on their dominance “relationship” based on comparing their relative sizes, and this would not even require individual recognition. Imagine that two unfamiliar vampire bats smell each other, and based on that first encounter, we can predict their social grooming and food sharing rates into the future. This observation that social relationship is explained by immediately observable phenotypic cues would refute how we all think relationship formation works. The concept of a relationship would predict instead that any “first impressions” could become overshadowed by social history, including the history of interactions with all the other relationships that form or fail to form. We tested these two predictions.
In both experiments, first few hours of contact among unfamiliar bats did not clearly predict the formation of allogrooming or food-sharing relationships over the next 10 months (study 1) or allogrooming over the next 4 months (study 2). These results are consistent with other past findings and present evidence (coming out soon) that social bonding in vampire bats is not reducible to the individual traits they have or to the behaviors they express at first encounter. In sum, social history does seem to matter. A general take home message of much of our recent work is that I think we can learn a lot about the functions of social relationships by tracking how they initially form.
Carter GG, Ripperger SP, Girbino V, Dixon MM, Razik I, Page RA, Hobson EA. 2024. Long-term cooperative relationships among vampire bats are not strongly predicted by their initial interactions. Annals of the New York Academy of Sciences. https://doi.org/10.1111/nyas.15241
Carter Lab 