twinblue{at}aol.com (TWINBLUE) wrote in message
news:...
> >I am not a biologist and have a question: Would there be fewer
> >roadkills at some point in the future? What I mean is that animals
> >have some tendencies that gets them confused and killed by uncoming
> >vehicles. Presumably, the genes that have these tendencies would be
> >killed off and mutations cause a future generation of for example
> >squirrels to get killed less frequently on the road. If so, how long
> >would it take for any change to happen?
> 
> Actually you are correct. This will happen.
> However the time frame is a difficult question. Some species may be quicker
> than others to accommodate human presence. And they may progress (?) different
> features at different rates. For example whitetail deer are so tame as to be
> just damn pests in many areas of the country but they show no sign of staying
> out from in front of cars. If the human species lasts long enough as a large
> population nearly every animal larger than rodents will either adapt to human
> presence or become extinct. This may take a really long time on a human scale.
> 

I would imagine that the absolute number of roadkill will be more
strongly determined by the frequency of road-crossings by animals and
the frequency (and speed) of vehicles on the roads, than by the
genetical composition of the animal populations. I'm not sure if
traffic is likely to get heavier in the future - maybe people will
become more environmentally conscious and tend to take buses or
whatever, which would reduce the number of vehicles on the road.  The
same would be true if people increasingly worked from home and had no
need to commute to and from work.  But increasing urban sprawl and the
destruction of natural habitats could reduce animal abundance, and so
regardless of an increase in traffic we could see a decrease in
roadkill simply because the animal populations have been decimated by
other means.

Having said that, I am aware of a fairly rigorous study which claims
to show that hedgehog populations close to some motorways in the UK
have responded to their new selection regime by becoming faster
runners, so I won't dispute that genetical evolution will be a factor,
albeit a small one.
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