Tag Archives: evolution

The Legless Snake: A Tale of Creationist Cherry-Picking

The Oxford Dictionary defines pseudoscience as “a collection of beliefs or practices mistakenly regarded as being based on scientific method.” I would add that pseudoscience can also be the purposeful misrepresentation of science to support an unscientific concept. A good example of this comes from a brief entry (and radio sound bite) on the website Creation Moments entitled “Legs Knocked Out from Under Snake Evolution”:

It’s rather interesting that evolutionists believe that snakes once had legs and lost them. This sounds very much like the Genesis account of the serpent in the Garden of Eden.

Obviously, evolutionists don’t accept the story of the first temptation. As far as they are concerned, the snake evolved from some reptile which originally had legs. But evolutionists have always tried to find some evolutionary advantage to losing legs and, thus, justify their theory. In 1973 an unpublished study suggested that garter snakes use 30 percent less energy for locomotion than they would if they had legs. That study was preliminary and never published. But that didn’t stop evolutionists from saying that they had found the reason that snakes don’t have legs.

Now, a much more exhaustive study done at the University of California at Irvine, has shown that this evolutionary explanation is false. Outfitting black racer snakes with oxygen masks and using modern precision equipment, including a snake-sized treadmill, researchers have shown that snakes use as much energy as a creature of the same weight to get around. The supposed evolutionary advantage to not having legs has disappeared under the bright light of scientific investigation.

And so yet another so-called scientific claim that the Bible has been proven wrong fails in the light of careful science.

This entry was recently brought to my attention as proof that the Bible is right and evolution is wrong. I have a policy of not trusting the claims of random websites (creationist or otherwise), especially when they don’t cite any sources. But I figured I would try to find these studies to see if they even existed, and, most importantly, whether or not the website was misrepresenting the information.

I dug around and found both the abstract of the unpublished 1973 study and the more recent paper that refuted its results. The abstract, entitled “Energetic Cost of Limbless Locomotion in Snakes,” was referenced in five papers and two books. [1] I can understand why it was cited for three reasons. First, the abstract appeared in a respected publication, the Federation of American Societies for Experimental Biology Journal. [2] This means it is a trusted source. Second, it was co-authored by Charles Richard Taylor (1939-1995), a noted experimental vertebrate physiologist from Harvard University. Third, the abstract provides data for the experiment.

A scan of the 1973 abstract.

The follow up paper was much easier to find than the abstract. I just used the bare bones details mentioned above to find a PDF of it online. Keep in mind that the Creation Moments entry was posted on June 14, 2013. [3] The paper was actually published on…wait for it…August 3, 1990, almost exactly 23 years ago to this day. Entitled “The Energetic Cost of Limbless Locomotion” (not to be confused with the similarly named abstract), the paper measured the amount of energy exerted by Black Racer Snakes (Coluber constrictor) based on the amount of oxygen they consumed at rest and during two kinds of locomotion (side to side slithering and caterpillar-like inching) at different speeds. [4] The energetic cost of slithering was found to be the same as locomotion for birds, mammals, and arthropods (insects, arachnids, and crustaceans) with the same mass. Caterpillar-like inching, on the other hand, used seven times the energy as these creatures. [5] The authors believe the 1973 study may have run the Garter Snakes (Thamnophis sirtalis), a species smaller than the Black Racer, at speeds too high for them to comfortably maintain, which hindered their ability to breath. This would explain the lower energy cost result from the original experiment. Most importantly, the authors believe the results of their own study suggest amphibians and lizards with long, slender bodies and small arms retained their limbs because it costs less energy than caterpillar-like inching while traversing underground tunnels. [6] That’s it; The paper mentions nothing about the study invalidating evolution.

The worst part is that I don’t think the creationists even read the paper. I believe they lifted the information from a news article appearing in the Los Angeles Times the same day the original paper came out. Entitled
SCIENCE / LOCOMOTION : Legs Knocked Out From Under Theory on Why Snakes Evolved,” the piece only briefly mentions the 1973 experiment before describing the results of the 1990 study. The first half of the article does not mention the names of the respective papers or the names of the respective authors. This is why the Creation Moments entry is so vague. The piece is also where they got their title from. [7] They didn’t mention anything from the second half of the article because it shows science, even back then, had more than one explanation for snake evolution:

Although snakes apparently conserve no energy by slinking along the ground on their bellies, other reasons may have influenced the loss of their limbs during the course of evolution.

“Without legs, snakes–because of their cylindrical shape–can squeeze through very small openings. With legs that might be impossible,” Jayne said.

C. Richard Taylor, a comparative physiologist at Harvard University who conducted the earlier snake studies, said the new research indicates that “snakes don’t optimize for low energy costs, but instead for the flexibility required to move across different terrains.”

This is just one of many examples of creationists cherry-picking and distorting the bits of science that they choose to accept. In this case, they think a single study from 23 years ago–which they did not read–trumps the science of today, as well as the over 150 years of concordant research by disciplines ranging from geology to genetics. It’s important to note that this sterilized (i.e. science lite) information on snake evolution has appeared in creationist literature since 1990. [8] This shows that they want their adherents to remain ignorant of the actual research fueling evolutionary theory. This ensures their religious beliefs will remain firmly entrenched in the bronze age, while the limit of human knowledge continues to expand into the future. And the fact that the author of the original study was willing to accept the new findings shows that science is self-correcting. This is how progress is made.

While squamates (lizards and snakes) are not my area of expertise, I think it’s safe to assume that science has made advances in the study of snake evolution in the last 23 years. Several species of fossil snakes with hind limbs from the late Cretaceous period (145-66 million years ago) have been discovered since the late 1970s. [9] Their exact position on the evolutionary tree (ancestral vs. derived) is still debated. At least one researcher believes these hind-limbed species are evidence that snakes have lost and re-evolved legs multiple times. [10] Creationists have happily promoted this disagreement, even going so far as to suggest that the centralized geographic range of these “leggy snakes” recalls the supposed archeopteryx hoax (a claim long discounted by science). However, the fact remains that there are physical fossils of snakes with hind legs in existence. In addition, creationists have to contend with the 2012 study that used an extensive dataset to show most snakes are derived from Scolecophidians, an infraorder of small, blind snakes that live underground. [11] It is generally assumed that snakes lost their legs to benefit early burrowing or swimming species because dragging limbs through these environments would have increased the energetic cost of locomotion. [12] This study seems to resolve the issue of terrestrial vs. aquatic ancestry. Furthermore, creationists have to contend with the existence of lizards with reduced or no limbs–i.e. legless lizards. For example, Lerista, a diverse genus of Australian Skinks, has body forms ranging from four limbs to none. Interestingly, Edward’s slider (Lerista edwardsae) has the same two leg configuration as the fossil snakes mentioned earlier. A 2008 study found that limb loss in Lerista has happened numerous times and as recently as 3.6 million years ago, a blink of an eye in evolutionary terms. [13] Individuals with reduced limbs are better at burrowing than those with prominent limbs;  therefore, just like snakes, the loss of limbs benefited these burrowing lizards. [14]

The Slow Worm (Anguis fragilis), a species of legless lizard.

In conclusion, I would just like to say that I have no problem with religious people who want to reconcile their faith with science. This is their burden to bear. Catholics, for example, are proponents of theistic evolution, gradual change over time directed by God. However, I do have a problem with the way creationists distort science in order to fit their religious worldview. They start with a conclusion (the Bible), and then they hunt for evidence to support it. This is the direct opposite of the scientific method. Worst still, educated creationists present distorted and/or vague descriptions of scientific research to the uninformed masses–who often don’t read the referenced material–in order to keep them ignorant of the actual state of evolutionary theory.

Contrary to the above claims, science still does not support the Genesis story of the serpent losing its legs permanently as a curse. The exact passage states: “And the Lord God said unto the serpent, Because thou hast done this, thou art cursed above all cattle, and above every beast of the field; upon thy belly shalt thou go, and dust shalt thou eat all the days of thy life” (Gen. 3:14). The scientific evidence points to early snakes losing their limbs to maximize their ability to burrow underground. Some snakes may have lost and re-evolved legs multiple times. This fact alone disproves the aforementioned curse. Most importantly, creationists will be hard-pressed to show that this serpent was capable of speaking and understanding human language.

Notes

[1] Michael Walton et. al, “The Energetic Cost of Limbless Locomotion”, Science 249 (3 August 1990): 524, accessed July 29, 2013, http://compphys.bio.uci.edu/bennett/pubs/97.pdf.
[2] Federation of American Societies for Experimental Biology. Federation Proceedings (Vol. 32). [Bethesda, Md., etc.]: Federation of American Societies for Experimental Biology, 1973, 422Abs, #1128.
[3] The entry does not have a date. However, this webpage and this YouTube video both date it to 6-14-13.
[4] Walton et. al. (1990): 524.
[5] Ibid, 525-526.
[6] Ibid, 526.
[7] “Legs Knocked Out From Under Theory on Why Snakes Evolved” vs. “Legs Knocked Out from Under Snake Evolution.”
[8] An entry from the 12-8-1990 edition of Awake!, a Jehovah’s Witness publication, alludes to this study: “Evolutionists assume that snakes evolved from lizards, but they are hard put to explain why lizards lost their legs. In 1973 an influential Harvard University study asserted that snakes evolved from lizards to conserve energy by slithering instead of walking. Recently, however, scientists at the University of California, Irvine, put that theory to the test. They outfitted some black racer snakes with tiny oxygen masks, put them on treadmills, and measured how much energy they actually do expend in slithering. The results: The snakes either used the same amount of energy as, or up to seven times more than, legged lizards walking the same distance.”
[9] The three most famous are Pachyrhachis, Eupodophis, and Haasiophis. For Pachyrhachis, see G. Haas, “On a New Snakelike Reptile from the Lower Cenomanian of Ein Jabrud, Near Jerusalem”, Bulletin du Museum D’Histoire Naturelle, Paris 4, no. 1 (1979): 51-64. For Eupodophis, see J.C. Rage and F. Escuillié “Un Nouveau Serpent Bipede Du Cenomanien (cretace). Implications Phyletiques.”, Comptes Rendus de l’Academie des Sciences, Sciences de la Terre et des Planetes 330 (15 April 2000): 513-20. For Haasiophis, see Olivier Rieppel et al., “The Anatomy and Relationships of Haasiophis Terrasanctus, a Fossil Snake with Well-Developed Hind Limbs from the Mid-Cretaceous of the Middle East”, Journal of Paleontology 77, no. 3 (May 2003): 536-58.
[10] Olivier Rieppel et al.
[11] John J. Wiens et al., “Resolving the Phylogeny of Lizards and Snakes (squamata) with Extensive Sampling of Genes and Species”, Biology Letters 8 (19 September 2012): 1043-46.
[12] Alexandra Houssaye et al., “Three-Dimensional Pelvis and Limb Anatomy of the Cenomanian Hind-Limbed Snake Eupodophis Descouensi (squamata, Ophidia) Revealed by Synchrotron-Radiation Computed Laminography”, Journal of Vertebrate Paleontology 31, no. 1 (January 2011): 5.
[13] Adam Skinner, Michael S.Y. Lee, and Mark N. Hutchinson, “Rapid and Repeated Limb Loss in a Clade of Scincid Lizards”, BMC Evolutionary Biology 8, no. 301 (11 November 2008): 6
[14] Annette R. Benesch and Philip C. Withers, “Burrowing Performance and the Role of Limb Reduction in Lerista (scincidae, Lacertilia)”, Senckenbergiana lethaea 82, no. 1 (2002-06-01): 107-14.

Bibliography

Benesch, Annette R., and Philip C. Withers. “Burrowing Performance and the Role of Limb Reduction in Lerista (scincidae, Lacertilia).” Senckenbergiana lethaea 82, no. 1 (2002-06-01): 107-14.

Federation of American Societies for Experimental Biology. Federation Proceedings (Vol. 32). [Bethesda, Md., etc.]: Federation of American Societies for Experimental Biology, 1973.

Haas, G. “On a New Snakelike Reptile from the Lower Cenomanian of Ein Jabrud, Near Jerusalem.” Bulletin du Museum D’Histoire Naturelle, Paris 4, no. 1 (1979): 51-64.

Houssaye, Alexandra, Xu FENG, Lukas Helfen, Vivian De Buffrenil, Tilo Baumbach, and Paul Tafforeau. “Three-Dimensional Pelvis and Limb Anatomy of the Cenomanian Hind-Limbed Snake Eupodophis Descouensi (squamata, Ophidia) Revealed by Synchrotron-Radiation Computed Laminography.” Journal of Vertebrate Paleontology 31, no. 1 (January 2011): 2-7.

Michael, Walton, Jayne Bruce C., and Bennett Albert F. “The Energetic Cost of Limbless Locomotion.” Science 249 (3 August 1990): 524-27. Accessed July 29, 2013. http://compphys.bio.uci.edu/bennett/pubs/97.pdf.

Rage, J.C., and F. Escuillié “Un Nouveau Serpent Bipede Du Cenomanien (cretace). Implications Phyletiques.” Comptes Rendus de l’Academie des Sciences, Sciences de la Terre et des Planetes 330 (15 April 2000): 513-20.

Rieppel, Olivier, Hussam Zaher, Eitan Tchernov, and Michael J. Polcyn. “The Anatomy and Relationships of Haasiophis Terrasanctus, a Fossil Snake with Well-Developed Hind Limbs from the Mid-Cretaceous of the Middle East.” Journal of Paleontology 77, no. 3 (May 2003): 536-58.

Skinner, Adam, Michael S.Y. Lee, and Mark N. Hutchinson. “Rapid and Repeated Limb Loss in a Clade of Scincid Lizards.” BMC Evolutionary Biology 8, no. 301 (11 November 2008): 1-9.

Wiens, John J., Carl R. Hutter, Daniel G. Mulcahy, Brice P. Noonan, Ted M. Townsend, Jack W. Sites, Jr., and Tod W. Reeder. “Resolving the Phylogeny of Lizards and Snakes (squamata) with Extensive Sampling of Genes and Species.” Biology Letters 8 (19 September 2012): 1043-46.

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