Snake on a wire

February 16, 2018 • 7:45 am

[JAC: In lieu of “readers’ wildlife” today, we have “Mayer’s wildlife”: His disquisition on snake locomotion. Be sure to keep those photos coming in, and don’t worry if you haven’t seen yours yet, as I have them all.]

by Greg Mayer

Matthew sends the following tweet of a tiger snake making its way along a wire fence.

At first glance, two things struck me at about this, aside from its generalized coolness. The form of locomotion is a typical one for snakes called lateral undulation, in which waves of muscular contraction alternate down the sides of the body. You can see the snake is pushing first on one side of the wire, then the other, in waves down the body. This is not unusual for snakes. And there are many arboreal snakes (vine snakes, parrot snakes, etc.) that habitually move along very narrow surfaces, such as vines and branches. The novelty here to me is the length of the narrow surface– most vine snakes frequently encounter crosswise vines and branches, so they don’t move for any great distance in a perfectly straight line along a narrow surface, as this snake is doing.

But its movements are not unprecedented. While checking into this particular mode of locomotion, I found the following in Carl Gans’ Biomechanics: An Approach to Vertebrate Biology (p. 93):

Other climbers show a fabulous ability to throw their trunk into multiple, regular, and controlled bends of very short radius. The African file snakes (Mehelya) apparently can travel along telephone wires with alternate half-loops hanging respectively over the left and right sides of the wire.

The second thing that struck me was that a tiger snake is not a vine snake of any sort– they’re terrestrial. So, climbing along wires is not where I would expect to see them. But that’s book knowledge, and perhaps Australian readers can enlighten us from experience.

On reflection, I was also struck by this being an example of what Gans called “excessive construction”– the ability of structures (and in this case also behaviors) to be successfully used in circumstances that were not part of the historical evolutionary development of the structure. Gans thought, and I agree, that such circumstances can be the basis for adaptation (i.e. heritable changes in the structure/behavior) to the new circumstances.  Again from Biomechanics (p. 14-15):

Gans provides a much more insightful view here of how functions change, and how new adaptations arise, than did Gould and Vrba in their largely unnecessary coining of the word and concept “exaptation“.

Gans, C. 1974 (1980). Biomechanics: An Approach to Vertebrate Biology. University of Michigan Press, Ann Arbor.

Gans, C.  1979.  Momentarily excessive construction as the basis for protoadaptation.  Evolution 33:227-233.

Gould, S.J. and E.S. Vrba. 1982. Exaptation- a missing term in the science of form. Paleobiology 8:4-15. pdf

Blackford 10, NOMA 0

June 14, 2009 • 7:41 am

Over at his website,  Metamagician and the Hellfire Club, philosopher Russell Blackford (who has been out of town), finally weighs in on the debate about accommodationism. His tactic is to take on Steve Gould’s concept of NOMA, or religion and science as “nonoverlapping magisteria.”

There is more to be said about this, but I’d like to spend more time on another claim, the idea, popularised by Stephen Jay Gould, that science deals with the empirical world, where it has authority, while religion deals with questions of how we ought to live, essentially the realm of morality, where it has authority. Thus, science and religion have separate spheres of authority and that do not overlap. According to this view, we are entitled to tell religious leaders to keep out of such matters as the age of the Earth and whether Homo sapiens evolved from earlier forms of life. However, so the idea goes, scientists should not challenge the authority of religion in the moral realm.

In my view, this is comprehensively wrong.

(Snipped . . . a lot of good arguments)

. . . I conclude that NOMA is comprehensively false. Religion is not confined by its very nature to the moral sphere and in principle it has as much authority in the empirical sphere as anywhere else. I.e., it could have made accurate empirical claims if really in receipt of knowledge from an angel or a god.

Conversely, science has at least as much authority as religion in the moral sphere: science cannot determine the ultimate point that morality should be aiming at, but neither can religion. Once we know what we want to achieve from morality, science is at least as well placed as religion to tell us how to achieve it, though we also need to rely on personal and historical experience, etc., since the most relevant sciences (such as psychology) are relatively imprecise and at an early stage of development.

However we look at it, religion is neither conceptually confined to the moral sphere nor authoritative within that (or any other) sphere. NOMA is a false doctrine. NOMA no more!

Of course, NOMA is a contentious doctrine. While I have put the case that it is false, that does not entail that, for example, science organisations should say that it is false, or that school students should be taught that it is false. Nor, however, should it be promulgated to students and the public as true. While I’m convinced that religion has no special authority in matters of morality (or in matters involving a supposed supernatural realm if it comes to that), other intelligent and reasonable people may disagree with this assessment.

All I ask from science organisations and school curricula is neutrality on the point, but I am personally convinced that NOMA is a completely specious philosophical doctrine. Those of who are not already convinced of the claims of religion should not buy it, and we should in no way be convinced by its proponents that we ought to back away from our critique of religion. Religion possesses no special authority in the moral sphere, and no one should persuade us to stop saying so.

I reviewed Gould’s lame book on NOMA, Rocks of Ages, in the Times Literary Supplement some time ago (need I say I was critical?), but it doesn’t seem to be online these days. You can find other reviews here.