Animals can be tricky to understand because they can’t speak to us in a form of communication that we can easily comprehend. But this obstacle hasn’t stopped experienced researchers from analyzing animal behavior in the field with the long-term goal of better understanding why animals do some of the weird things they do.
One of the latest studies to advance our understanding in this sector is one published just this past week in the journal Cell Biology by team of colleagues from Ohio State University and the Smithsonian Institute. Based on high-resolution proximity sensor data, the researchers were able to discern strong social bonds in female vampire bats even when they had originated from starkly different social environments.
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Female vampire bats are known for their kind acts of hospitality toward one another, but the same can’t be said for male vampire bats, which are highly territorial and spend most of their time clashing with others. The team was particularly interested in learning whether captive-born vampire bats and wild-caught vampire bats would form similar bonds, and to that end, a research experiment began.
Proving a social bond between two animals can be challenging, but the researchers had at least one good trick up their sleeves. Playing on the female vampire bats’ natural hospitality for others, the researchers fasted the bats individually to observe what would happen next. The findings were both gut-wrenching and heartwarming at the same time.
When one female would appear hungry, another well-nourished female would come to its rescue by quite literally regurgitating whatever she might’ve eaten previously and then sharing it with the starving specimen. These same females would then be observed grooming one another, purportedly out of bonding and comfort.
The researchers kept the bats in captivity for almost two years before equipping each one with a high-resolution proximity sensor and finally releasing all the bats in the wild at the same spot where the original wild catches had been captured. The sensors would enable the researchers to track which bats spent time with whom, and from this data, they could determine if the social bonds remained post-wild release.
Perhaps unsurprisingly, those bats that developed close social relationships in captivity continued to comfort one another in the wild setting – at least for a while.
“Our findings demonstrate this method of high-resolution tracking can reveal relationships that have ecological consequences,” elucidated Gerald Carter, a co-author of the study. “We can now see some animal relationships are independent of setting.”
Not even a week after the big release, however, the captive-born vampire bats left the wild-caught colony. As it would seem, they were struggling to fit in with the rest of the group and eventually flew off to find a new home for themselves.
“It is a neat illustration that shows how the social structures of animals depend both on internal preferences they have for each other, but also the external environment because not all bonds lasted,” Carter continued. “Even in a completely different setting, these bats were still attracted to each other.”
The findings are particularly interesting because it reveals how friendships formed out of necessity can last and ensure survival when the need arises. After the vampire bats were released to the wild, however, that necessity dissolved, and the animals returned to their old ways. Perhaps future research could determine why this happens and discern whether a longer bonding period would enable longer-term relationships in the wild.