Does An Adaptation Have to Be Logical?

This anole regrew his tail.. is it logical to sacrifice your tail to save your life?

For the past few weeks I’ve noticed a common thread in my approach and attempts to relate information about wildlife to the public.  In my quest to make things digestible I often resort to applying logic.  Why do some species of dolphin swim upside down?  Well, its complicated. 

We think it has a lot to do with their vertebrae.  Most cetaceans have fused neck bones, so they can’t turn their heads like we might.  If a dolphin wants to see what’s around it, both above and below, it needs to turn its body.  Thus, perhaps some dolphins swim upside down for the same reason that people – when tapped on the shoulder – will turn around to see who did the tapping.  They want to be aware of things in their environment.

Its an explanation that approaches some tenuous concept of “making sense”.  Its logical and readily acceptable.  But the thing is, do adaptations – behavioral or morphological – have to be logical?  Do they have to make sense? 

Its certainly arguable and a point that many evolutionary biologists will use as an achor for their careers.  If an adaptation doesn’t seem to serve a purpose there are two questions to ask it seems.  A) Is there a purpose served that we simply do not yet see?  Or, B) Is this adaptation simply neutral in the current environment and neither beneficial nor particularly harmful to the animal?  Maybe the neutral adaptations – those that do not impact survivorship – are prone to be illogical. 

Deep down, I think most people want to understand even the most baffling of characteristics in a species.  Typically, for the human mind, we logically organize all the experiences and information contained within a day in our minds for later perusal.  But I worry whether or not our current understanding of wildlife and science is perhaps inhibiting my ability to be an effective educator.  What do I mean? 

Well, perhaps there is nothing logical at all about dolphins swimming upside down.  Sure they may have fused neckbones and can’t tilt their heads to as easily see up and down but they sure do have echolocation and they typically live in social pods of several pairs of eyes.  I’m not proposing that echolocation is a kind of side scanning sonar – although they think beluga whales can use ricocheted surface sounds bounced off of overhead ice pack – but the fact is that we aren’t always entirely sure of the answers to simple questions.  And the answers may not always be logical. 

I once mused about the reason for an animal as large as a whale shark to wear camouflaging spot patterns on their skin especially since they only need to stalk plankton!  Perhaps there are animals large enough to eat adult whale sharks in the ocean that we havent discovered.  Perhaps they are leftover patterns from the juvenile stage that really does have predators.  Perhaps the spots are sexy to other whale sharks.  But maybe, just maybe, there is absolutely no reason for the spots at all.  Maybe they just exist.