Re: why is the tip of vulpes vulpes' tail white?

Date: Thu Dec 13 17:21:41 2001
Posted By: Rob Campbell, Ph.D Candidate, Oceanography, University of British Columbia
Area of science: Zoology
ID: 1008258361.Zo

Message:

Hi Amanda:

It is very difficult for scientists to answer "why" questions - that's often the realm of philosophers! The way biologists usually answer "why" questions is with Evolutionary Theory (You can find a great introduction to Evolutionary theory and Natural Selection here). The basic idea is that if an animal has a certain feature (such as a different colour at the tip of its tail, or spots, or a really long neck), there must probably be a reason for it. For some reason that feature makes it a little more likely for that animal to do better than animals without that feature (e.g. not get eaten, find more or better mates), and therefore pass its genes on to the next generation.

So, in the case of the Red Fox (vulpes vulpes), there are a few possible reasons (us scientists call them hypotheses) that it has that white tip:

As an antipredator defence. It's possible that if something is attacking a Red fox, the white tip will distract it, or draw it away from the Red fox's head, so it will be more likely to get away more or less unharmed. Animal behaviouralists call this the "predator-deflection hypothesis", and it is the most widely accepted one.

A few other possible reasons for having a white tip:

A species recognition marker.

A warning signal (either to warn other foxes of danger, or to warn a potential predator that they are not to be messed with!)

A courtship display for use in mating

A "follow me" signal, such as may be used by pups to follow their mother, or when hunting in groups.

Something else that nobody has thought of yet!

So, the point here is that it could be any one of many possible reasons (or most likely some combination of them). We really don't know (and we can't ever know), because it is something that probably arose during the evolution of what we now call the red fox. Evolution is not something that a person can go out and measure - it's something that occurs over many many generations of an animal. Scientists have only been around observing things for the last couple of hundred years or so, but foxes have been evolving for thousands of years - so we're missing most of the story! What we have to go on is fossil evidence (which of course doesn't tell us anything about the colour an animal was, only what its skeleton looked like), and what we know about foxes (and similar animals) now. We can speculate about what happened, but we can never know for sure. That is one of the reasons that the Theory of Evolution is so controversial!

A lot of this came from a paper I found on the web: Spots, stipes, tail tips and dark eyes: Predicting the function of carnivore color patterns using the comparative method by Alessia Ortolani of the University of California Davis. It's kind of heavy going for anyone who's not an evolutionary biologist, but if you're interested in learning more it's definitely worth a look.

Hope that helps!
Rob Campbell, MAD Scientist

Current Queue | Current Queue for Zoology | Zoology archives

Try the links in the MadSci Library for more information on Zoology.