Science Sunday: Otter Penises & Pollution
For those who don’t pay much attention to furry things in British rivers (and really, why would you?) you might be interested to hear that the otter population in my homeland is on the way up and recovering from their rapid decline in the 1970s. Now, what seems to have been the cause of their population crash was runoff of certain pesticides into rivers, but despite the fact that these pesticides are now banned, the otters have been facing a strange dilemma in the crotch area.
This dilemma, a shrinkage in the penis bone of male otters (male, for obvious reasons, penis bone because most mammals have them, it’s humans (and other apes) that are the oddballs in this case), appears not to be caused by the otters’ old enemy: POPs or persistent organic pollutants. Although from the name alone you can tell that these chemicals stick around for a while, there doesn’t seem to be any link between these chemicals and the penis problem.
It seems that the problem is still pollution-related though, albeit through chemicals that affect hormone circulation known as EDCs or endocrine disrupting chemicals. Although these chemicals can be found in nature, there are synthetic varieties that may have ended up in these rivers, and, as you might suspect, have disrupted the effects of hormones in otters, particularly the reproductive pathways; hence the lighter penis bone.
We’ve caused a lot of these kind of mix-ups as we’ve spread our influence across the world. In fact, the BBC article that drew my attention to this story draws an interesting parallel to fish species that have developed female characteristics in males, such as testes containing eggs. For animals that work through delicate chemical processes (like all of us I suppose, although water is a more ideal conduit for chemical exchange than air given what we’re made of), the chemical imbalances caused by pollution can have unforeseen consequences that we only touch on years later. I’m sure when people were trying to work out ways of stopping their crops getting eaten they didn’t think a process that could grant their wish would screw up development in river life, and if they did, well, they could have said something earlier.
The problem with the spread of anthropogenic pollutants around the world, especially as the human population continues to explode, is something that could cause many more incidents like this on a more frequent basis, especially if our activities continue to be as intense as they currently are. For example, we know that the gender of sea turtles depends on the temperature of their eggs during their development, and as climate change pushes temperatures higher, the gender ratio of these creatures is bound to become imbalanced, which will in the least, make the population unstable. Conditions that creatures previously had centuries and millennia to adapt to are being changed so quickly that adapting is basically out of the question; there just isn’t enough time. The best we can do is identify the causes of these problems and try and make up for them. It would be nice if this was as simple as it sounds, wouldn’t it? Perhaps, at least for otters, we can identify the cause of their problems before it does more serious damage to their populations.