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Altruism as Darwinian natural selection: How rats help natural selection

Carrying some groceries home from the plaza today, I came across an interesting sight:

Note: More altruism vs. Darwinism stories here.

A rat in broad daylight. We see this sometimes here, in good years for rats. The rat rushed into traffic and got its right hind foot run over.

I wasn’t about to rush out to rescue it. I knew it would bite very deep, and might have rabies.

(Rats are nocturnal, generally. A common feature of rabid nocturnes is diurnal restlessness and weird behaviour. Indeed, a biologist friend commented that about half of skunks seen in broad daylight have or are carrying rabies. So why not rats?)

The anti-rabies series of injections is not quite as much fun as the Cannes Film Festival. If all you want is second place, for pure, unadulterated fun, okay maybe.

I hoped someone would just run over the tormented, whirling rat and end its misery.

But car after car swerved into the left lane, to avoid further harming it.

I was becoming concerned, but finally someone did just run it over and obliterate it, which was really the only solution.

Now, what, I wonder, is the Darwinist explanation for what I witnessed, given that rats are widely regarded as a disease vector, routinely killed, and once carried off a third of the population of Europe (bubonic plague)? Obviously, that rat was helping natural selection in some way, right? Someone can get a grant for a research paper explaining all this, according to Darwin. I think, knowing my own turf, I’d come up with something that did not involve Darwinism.

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7 Responses to Altruism as Darwinian natural selection: How rats help natural selection

  1. So what’s your ‘non-darwinist’ explanation?

  2. jurassicmac: I’m just guessing, and obviously can’t speak for Denyse, but I bet it has something to do with God.

    Anyways, keep in mind that a person driving in their car probably feels very safe from any threat posed by the rat, except but one: suppose said driver actually does run over the rat. What then? Why, rat guts all over the car tire. And then what? Well, the driver potentially carries infected rat guts all the way home to possibly spread disease in their home. And at the very least the driver has the hassle of having to wash the rat guts off the tire.

    So, what is the most selfish thing a driver can do when confronted by a whirling rat in need of assistance? Swerve to miss it and let the next person deal with it! How noble!

  3. jurassicmac and NormO, if I know my own city, I would explain it like this: The drivers just do not want to be the one to do it, period. There is no big calculus involved.

    People hire pest control services, knowing full well that the service will kill rats, mice, and cockroaches, and trap and ship native fur bearers to remote locations, from which they will not likely return to the city. But actually doing it oneself feels like a different matter.

    That is a common feature of human psychology: Delegation of moral responsibility eases the mind.

    The flattened rats I have seen did not really make much of a mess; they were just flattened, period, and the guy driving the street vac could pick them up easily and safely.

  4. But I do the same thing with roadkill; I intentionally swerve to miss it. I know full well that it’s dead, but, like NormO said, If I had a choice, I’d rather it not be all over my tire. If this is in fact the most plausible explanation (I think most people avoid running over all obstacles in the road, biological in origin or not) it is quite a stretch to claim “Darwinism cannot explain this altruistic behavior,” when you can’t really demonstrate that it’s anything like altruism in the first place.

    But say for sake of argument it was altruism at work. are you claiming that God instilled in us as part of our altruistic nature an affinity for saving these little ‘disease vectors’ at risk of crashing our car?

  5. Sorry, Denyse, but I think the aversion to kill small furry animals – if it is actually an instinct – is easily overrun. For instance, in New Zealand, drivers are happy to kill any possum that happens to cross their road.

  6. jurassicpac at 4: But it was actually and obviously alive.

    Kontinental: That is precisely what interests me in the exceptions, one of which I witnessed that day.

  7. Obviously, that rat was helping natural selection in some way, right?

    I’m not sure I understand what you mean by that? Could you elaborate?

    And I don’t want to endorse any genetic reasons for swerving to miss a pest animal. As far as I know, the behavior isn’t (strongly) genetically determined. But how about this: when dealing with a carrier of disease, the safest course of action is to avoid contact unless you’re in your home territory. Trying to kill it puts you at risk for infection, which might make sense if it’s in your back yard (don’t want it to bite the kids), but not if it’s miles from your usual stomping grounds (then it’s someone else’s problem).

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