April 23 - Dolphins Are Different...

Dolphins are different... Different from us and from one another! Here's an example: the tagged Franciscana dolphins have stayed in or VERY close to the mouth of the bay the entire time. I study Atlantic bottlenose dolphins and as a species, they show far more variation in the way they behave depending on whether they live close or far from shore---to the point that some taxonomy folks wonder if there might be subspecies or two different species (but I'll leave that debate to those who specialize in taxonomy).

But with the coastal/estuarine species like the Franciscanas, we do not yet know much about the inshore/offshore distribution. Data from Franciscana dolphins caught in fishing nets suggest that adult males may be found further offshore than mothers with calves. This is consistent with our three years of tagging experience, in which we have caught mostly adult females and juvenile males - no adult males - in the shallow inshore waters.