Then I found a new species in Bocas del Toro, Panama, where I did a ten-year project inventorying all the islands. On the most remote island we had a small fruit eating bat, an Artibeus, that was a giant compared with its mainland relative. The Streblid batflies that we collected from it proved to be a new species different from the fly on the bat's mainland relative but similar to it. The flies had differentiated as the bats evolved.
Here's another story about how projects interrelate. I did another ten-year study of demography and natural history of bats on Barro Colorado Island (BCI) beside the Panama Canal. In those ten years, we marked about 35,000 bats and caught back 15,000 of them for a total of 50,000 capture records. Getting all the information out of that huge database will take me all the rest of my natural life and those of other people too. There's nothing else like it in the world.
On Barro Colorado Island, we found a relative of the Bocas Islands bat. It had a very small home range. We usually caught it year after year practically in the same mist net at the same site. So we know that it doesn't fly very far and it doesn't go from BCI to the mainland, for example, which is less than a kilometer distant in some places. We got no recaptures of island bats on the mainland.
The Bocas Islands were formed by rising sea level, which isolated hilltops that eventually became islands. By using dates from coral cores and pollen cores in the western Caribbean, we were able to put dates on the emergence of the various islands. We found that Isla Escudo de Veraguas, where this new bat lives, is at most 9,000 years old. So, sometimes evolution can proceed very rapidly.
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