Happy World Snake Day!

July 16, 2020 • 1:15 pm

by Greg Mayer

Jerry noted this morning that it’s World Snake Day, but I thought I’d add to the festivities by sharing a couple of photos of my Ball Python (Python regius), Vivian.

Vivian, a Ball Python, Python regius, 16 July 2020.

I lifted Vivian’s hide box to take the photo, and she was mildly perturbed, so she defensively hid her head in her coils.

Vivian, a Ball Python, Python regius, hiding her head, 16 July 2020. Note the tiny  hind leg (“spur”) visible at the base of her tail.

The Department of Defense Partners in Amphibian and Reptile Conservation has sent out a great set of links for World Snake Day, put together by my friend and colleague Rob Lovich. There’s loads of stuff in these links– look around. I’ve brought to the top of the list a shutterfly album of a great diversity of snakes. If you don’t have time for more, open up that album click on the slideshow, and enjoy! (It works best if you have dual monitors, one to work one, and one for snake pix.)

Here’s the album: Shutterfly Snake Pictures (over 800 pictures). From DoD Parc:

Tomorrow [i.e. today] (July 16th) is World Snake Day! In celebration of this event and the important ecological value snakes play in the ecosystems of military lands, we would like to highlight some snake-focused DoD Partners in Amphibian and Reptile Conservation (DoD PARC) products below.

We hope you enjoy learning about snakes through the various DoD PARC products below.

Snake Pictures, ID cards and Podcast:

YouTube Videos

Posters

Fact Sheets

Reports

Snake Guides

DOD PARC Logo

The Timber Rattlesnake (Crotalus horridus) was chosen on our logo to reflect the long-standing relationship DoD and the Military Services have with protecting both our nation and its resources, including snakes. Ultimately, the use of this species is meant to represent how DoD protects the natural resources with which it has been entrusted, and how those resources in turn provide for and protect the military’s ability to prepare for its war-fighting and peace-keeping duties.

If you’re wondering why the military has a unit devoted to amphibians and reptiles, the military must follow environmental and conservation laws (unless specifically exempted); there are practical issues for the military involving venomous reptiles; and recall that Darwin traveled around the world largely by courtesy of the Royal Navy. The U.S. Navy published, with the assistance of the American Society of Ichthyologists and Herpetologists, the classic Poisonous Snakes of the World:

If you want to learn more about snakes, I recommend, as I have before, Harry Greene‘s Snakes: the Evolution of Mystery in Nature as a good, well-illustrated, introduction to their natural history and diversity


Greene, H.W. 1997. Snakes: The Evolution of Mystery in Nature. University of California Press, Berkeley.

Minton, S.A., H.G. Dowling & F.E. Russell. 1965. Poisonous Snakes of the World: A Manual for Use by U.S. Amphibious Forces. NAVMED P-5099. Bureau of Medicine and Surgery, Department of the Navy, Washington, D.C.

h/t: Caroline

Is Edward Drinker Cope beyond the pale?

July 6, 2020 • 8:45 am

Note from Professor Ceiling Cat:  Be aware that this post is not by me, but by Greg. Not that I disagree with it, because I don’t, but people are always giving me credit for Greg’s posts, and he deserves any encomiums or opprobrium. So note the title line below. The story is a familiar one with a twist: the erasure of someone for views that we no longer find acceptable, but in this case it’s a scientist.

There will be a second installment of l’affaire Cope this week, hinted at in Greg’s last line.

by Greg Mayer

The answer to the question in the title of this post is, “Yes.” But first, some background on Edward Drinker Cope (1840-1897).

Edward Drinker Cope, 1840-1897.

Cope was a Philadelphia Quaker who was one of the most prolific vertebrate zoologists of the 19th century. He began publishing as a teenager, and published about 1400 papers in his relatively short life. The herpetologist Kraig Adler (1989:46-47) called him “America’s greatest herpetologist,” and added that his “most epochal contributions were to vertebrate paleontology.” Paleontologist Kevin Padian (1998) wrote, “The most versatile American vertebrate zoologist of the 19th Century, and perhaps the 20th, E.D. Cope has touched the lives of every one of his professional successors through his astonishing record of collection and publication.” I have read and used his work in my own research, and I own copies of his two great monographs on the North American herpetofauna, “The Batrachia of North America” (1889) and the posthumous “The crocodilians, lizards and snakes of North America” (1900). (We’ve encountered Cope before here at WEIT, with regard to the false claim that he is the type specimen of Homo sapiens.)

Although still well known among vertebrate zoologists and paleontologists for his anatomical, systematic, and faunistic contributions, Cope’s general evolutionary views, usually called “Neo-Lamarckian”, are today little known or discussed; his Origin of the Fittest (1886) and Primary Factors of Organic Evolution (1896) are not high on modern reading lists. The founders of modern evolutionary biology (Th. Dobzhansky, Ernst Mayr, and even the paleontologist G.G. Simpson) had little to say about him, and if he’s mentioned in a modern textbook at all, it’s for Cope’s Rule (the general tendency for  evolutionary lineages to increase in average size). Broad histories of evolutionary biology have a bit more to say (Bowler, 2003), and specific histories even more (Bowler, 1996).

To the general public, Cope is best remembered (if at all) for the “Bone Wars“, his intense rivalry with O.C. Marsh of Yale to discover, collect, and describe the great vertebrates of the American West, a feud that was the subject of several popular books (e.g., Wallace, 1999).

When John Treadwell Nichols at the American Museum of Natural History founded a journal of cold-blooded vertebrates in 1913, he named it Copeia, after Cope.  (Naming journals after a prominent figure in this manner is not uncommon; two others that pop to mind are Treubia and Brenesia.)

A few years later, the American Society of Ichthyologists and Herpetologists (ASIH) was formed, and after a few more years, in 1924, the Society took over publishing of the journal. An editorial note in January, 1924 (an issue published during the transition to the ASIH as publisher), stated the journal’s scope:

Due to exigencies of space, articles for publication in Copeia must be brief and restricted to observations on taxonomy, distribution, structure and habits. Controversy and opinion will rarely be printed.

On Friday, the Board of Governors of ASIH renamed the journal Ichthyology & Herpetology; Cope is now officially beyond the pale.

The process by which Cope’s name was to be removed became known to the membership on June 18, when members—I’ve been one since I was in high school—received an email from the President and Editor. The letter to members succinctly stated the problem, the proposed remedy, and the process:

Our journal’s namesake, E.D. Cope, held and published racist and misogynist views that our current membership finds abhorrent. The ASIH will begin addressing this matter. The Executive Committee of the ASIH is in favor of changing our journal’s name and is taking step to begin this process. We will bring this matter to our Board of Governors, to the appropriate ASIH committees, and to the ASIH membership for consideration.

The letter mentions repeatedly that the membership is likely unaware of Cope’s views:

Our goal is not in seeking the demonization of Cope. Rather we wish to honestly address one of our own blemishes. We have long ignored this particular blemish; much of our membership is not even aware of Cope’s racist perspectives.

History can be taken out of context. Indeed, Cope’s views were held by many (perhaps most) of his contemporary 19th Century scientists. However, his views on race, society, and eugenics were very prominent. Because he has been a titan of both ichthyology and herpetology (and perhaps because few modern members know his views), for a century we have looked past the bad to focus on his accomplishments. But his views on race and society were very public and, unfortunately, published as purportedly scientific articles. In a few instances, these views were part of policies agreed to by the ASIH.

Many ASIH members may not know that we have been having these conversations for years, even decades. From our perspective, it is time to think hard about the messages behind whom we honor and hurt with our statues and monuments, and with our building and journal namesakes. We have an opportunity.

From such a letter, I think it fair to assume that the membership would be informed about Cope, and then asked to consider the action proposed by the Executive Committee. The members were neither informed nor consulted. On Saturday, June 27, it was announced that the Board of Governors was voting to change the name, and it would be over within a week. I wrote to the Executive Committee and Board of Governors on June 30 as follows (in part):

I had expected that there would be a broader consultation. Although the constitution may allow the Board of Governors to take action on its own, I don’t see how doing so in the time frame contemplated can be construed as bringing the matter “to the ASIH membership” in any sense whatsoever.
In your message of the 18th, you acknowledge that few members of the ASIH are aware of the views which Cope held which are to be censured. That is certainly the case for myself. While I have read and used Cope’s herpetological works, I must admit that my knowledge of his life is limited to about the contents of Kraig Adler’s biographical sketch of him in Contributions to the History of Herpetology, and to the fact that he engaged in a sometimes unsavory paleontological ‘war’ with Marsh. I have never had any reason to seek out or consult his social views.
I urge you to begin the process of bringing the matter to the members’ attention by informing us of what it is that Cope did that merits censure. Once the ASIH’s members are well informed, then it will be possible for the Society to take actions that will have the “buy-in” of the membership.

Having seen arguments that it is justified (and not merely misdirected) to take down statues of Ulysses Grant, I wanted to learn myself more about Cope. There are two biographies of him: Henry Fairfield Osborn’s Cope: Master Naturalist (1931), and Jane Pierce Davidson’s The Bone Sharp: The Life of Edward Drinker Cope (1997), but with no access to libraries possible (and of course no time to read the books, given the one week time frame), the best thing I could find to inform myself was Kevin Padian’s (1998) long, thoughtful, review of Davidson. Padian finds the book useful, but laments that Davidson has written a purely “personal biography”, which does not engage with Cope’s science or the culture in which he was brought up. Here’s the part of his review that addresses Cope’s views on human races:

Davidson’s principal interests in Cope’s theoretical ideas run more to how his views of human differences were used by others, scientists and social commentators alike, in some particularly repugnant campaigns against blacks. Cope was a thoroughgoing racist, though like many such, he liked and respected individuals among those groups whose ethnicity he generally disdained. Cope’s views went beyond the benign sectarian xenophobia of most Quakers (including his father), who had a long tradition of working for emancipation and amelioration of the American Negro. Cope congenially disparaged blacks, Asians, Irish, Jews, Mexicans, New Mexicans, and various European groups, though he generally respected the Indians whom he met out West. He regarded whites as most advanced among human races and looked for “apelike” characters in other races as evidence of arrested development from more primitive Quadrumana (Primates). Negroes were to him the most ape- like, with poorly developed social and intellectual abilities that would only atrophy apart from association with whites. He opposed slavery and racist violence such as lynchings, though his Quaker heritage gave him the opportunity to avoid serving in any capacity in the Civil War. He advocated shipping freed slaves to Africa, not so much to deny them whatever benefits of freedom might await them in America as to return them to a milieu in which it might not be so difficult for them to succeed, intellectually and socially. In his view, this position (shared by other strange bedfellows at the time, including many Northern and Southern politicians) was scientifically justified: his researches indicated that the skull sutures of Negroes closed earlier in ontogeny than in whites, indicating limited development of the brain. Davidson presents a spectrum of social commentators who used Cope’s findings and went farther beyond them than Cope, she thinks, ever would have done, and what she presents is truly disturbing. Weaving the relatively dispassionate scientific inquiries of Haeckel and Herbert Spencer about Cope’s views on racial differences with the frightening use of them made by the anatomist Robert W. Shufeldt, Davidson masterfully shows how thin was the line dividing science and social engineering. Shufeldt, whose Myology of the Raven and other works are still well known, was particularly over the edge in both his social views and his sanity. Davidson is probably correct in concluding that Cope would never have condoned the social engineering of the Negro that Shufeldt and others suggested, but it is difficult to deny that Cope’s “scientific” studies lent a veneer of authority to the polemics.

Trying to inform myself was only for my own edification, because the Board of Governors did indeed act in less than a week, without consideration by the membership. After the vote was concluded, the information sent to the Board of Governors was shared with the membership, including a link to an article from 1890, documenting some of the views alluded to by Padian. (I still don’t know anything about the objectionable “policies agreed to by the ASIH.” What are they? Are they still in effect? Have they been changed? Cope, of course, being long dead at the time, had no hand in establishing ASIH policies.)

So, it’s clear that Cope held and published views that are reprehensible. We all need to consider, what is to be done in such cases?

[JAC: Stay tuned for Greg’s next installment.]


Adler, K., ed. 1989. Contributions to the History of Herpetology. Contributions to Herpetology, No. 5. Society for the Study of Amphibians and Reptiles, Oxford, Ohio.

Bowler, P.J. 1996. Life’s Splendid Drama: Evolutionary Biology and the Reconstruction of Life’s Ancestry, 1860-1940. University of Chicago Press, Chicago.

Bowler, P.J. 2003. Evolution: The History of an Idea. 3rd ed. University of California Press, Berkeley.

Cope, E.D. 1886. Origin of the Fittest. Appleton, New York. BHL

Cope, E.D. 1889. The Batrachia of North America. United States National Museum Bulletin 34:1-525. Reprint, 1963, Eric Lundberg, Ashton, Maryland. BHL

Cope, E. D. 1890. Two perils of the Indo-European. The Open Court 3:2052–2054.  https://bit.ly/TwoPerils

Cope, E.D. 1896. Primary Factors of Organic Evolution. Open Court, Chicago. BHL

Cope, E.D. 1900. The crocodilians, lizards and snakes of North America. Report of the U.S. National Museum for 1898:153-1270. BHL

Davidson J.P. 1997. The Bone Sharp: The Life of Edward Drinker Cope. Academy of Natural Sciences, Philadelphia. (Not seen.)

Osborn, H.F. 1931. Cope: Master Naturalist. Princeton University Press, Princeton, N.J. (Not seen.)

Padian, K. 1998. (Review of) The Bone Sharp: The Life of Edward Drinker Cope, by Jane Pierce Davidson. Journal of Vertebrate Paleontology 18:243-246.

Wallace, D.R. 1999. The Bonehunter’s Revenge: Dinosaurs, Greed and the Greatest Scientific Feud of the Gilded Age. Houghton Mifflin, Boston.

Readers’ wildlife photos

September 15, 2019 • 7:45 am

Although I have a few more batches of wildlife photos to post, I’m running low, and may have to put up photos more sporadically. If you have good photos to send, by all means submit them.

Today we have some diverse photos by regular Mark Sturtevant, whose flickr photo site is here. Mark’s notes are indented.

Here are some photos from about a year ago. Enjoy!

The first picture features a male Phalangid (aka ‘harvest-person’), possibly belonging to the genus Leiobunum. A feature of males is their rather elaborate pedipalps that are used in a precise way to hold on to females during mating. I have pictures of that to show later.

Next are several ‘candy-striped’ leafhoppers (Graphocephala coccinea) that were in my back yard. People are sometimes surprised when seeing pictures of them, but actually these diminutive insects are quite common. Most are red and blue, but some are red and green.

The butterfly in the next two pictures is the red-spotted purple (Limenitis arthemis). This one was missing most of one of its wings, so I had fun digitally replacing it with the ‘good’ wing. Hard to tell which one it is now.

I had long been curious about these tall, thistle-like weeds that are also shown, so I showed them to my Botanist-wife and she told me the plant is called teasel. This is an invasive species, and now I see it everywhere. I feel conflicted about that since it is interesting in its own right while also being a magnet for insects.

At the shore of a lake I came across a giant swallowtail butterfly (Papilio cresphontes) that was ‘puddling’ on the wet sand to get nutrients like salt and amino acids. This was a nice surprise since these very large butterflies (the largest in North America) seem to always be flying non-stop. ALL of my other pictures of them are rather blurry as I have never quite figured out how to freeze motion with shutter speed and/or flash.

Next is an odd little moth that I always called an ‘airplane moth’. But the internet does not seem to recognize that name and there it is a plume moth. It looks to be the grape plume mothGeina periscelidactylus.

We seem to be having a ‘run’ on Lepidopterans. The lovely Saturniid moth in the next picture is the tulip-tree silkmoth (Callosamia angulifera). I do recommend that readers double click on this, for she is spectacular. Tulip tree silk moth larvae are almost exclusively found on tulip trees.

The story here is that I had come across a dead and leafless tree that someone had dumped in a local park (no idea why), and it had several pendulous cocoons on it. Most were empty, but two were still occupied. These were brought home to see what might emerge. The first that emerged revealed the identity of the mystery cocoons, but the moth had badly deformed wings. Fortunately, the second was this perfect female! Before she was completely hardened and so unlikely to fly, I managed to get this picture by hanging her in the opening of our garage. From there I could sit back in a chair, with the camera on a tripod, and poke her (gently) with a thin stick to get her to raise her wings before I snapped a picture. She was of course released that evening.

Next are some lace bugs, and the reason for their name is obvious with the winged adult. Different species of these plant-sucking insects are found to favor different host plants. I can get a couple pg different species when sweeping with a net, but without host plant information it would be difficult to identify them to species. Not so for this one, which is found on the leaves of linden trees. This is the ‘linden lacebug’ (Gargaphia tiliae).

In the final picture we have a very young gray tree frogHyla versicolor. Youngsters are green, and many are gray when mature. This little cutie would barely cover a nickel.

Readers’ wildlife photos

May 26, 2019 • 7:30 am

Kiwi reader Keith sent a batch of photos which he’ll leave to you to identify. His notes are below:

Here is a collection all taken with my cellphone, I’m going to leave them “silent”. I have no idea what some species are, while others speak for themselves.

They’re all taken around or from my home with my cellphone. Laingholm, Auckland is where i live—in New Zealand. They are spread over time: the large moth on my hand has been passed down through a few phones…

Put your identifications in the comments.

And another NZ photo taken by reader Gary Radice:

This is from a recent trip to New Zealand. We got all excited when we saw this tame little fellow (gal?) in our camp site, thinking it was a kiwi. We were only a little disappointed to find out it was a weka [Gallirallus australis]. But since we had never heard of wekas, that turned out be fun, too.

 

A lizard that breathes underwater

April 5, 2019 • 3:38 pm

by Greg Mayer

This beats eating and swimming underwater: Lindsey Swierk, of SUNY Binghamton, reports, in the latest issue of Herpetological Review, that Anolis aquaticus can breathe underwater! Here’s a video she posted at Anole Annals:

The lizard, of course, is not breathing water; rather, it is breathing air that is trapped around it’s body, which it then visibly exhales in a bubble, and then “rebreathes”. I could not tell from how far around the body air was being drawn to the nostrils, but it seems to include at least the head. The longest she has seen them stay down is 16 minutes. It has long been noticed that air can be trapped around an anole’s body when it’s placed in water, and I’ve wondered whether that air might enable an anole to float longer or higher in the water (perhaps aiding “occasional transport”). But Lindsey has placed these casual observations on a much firmer basis, and recorded, for the first time to my knowledge, that the lizards are breathing; that’s something I never suspected. She proposes a “scuba tank” explanation for the behavior– that the lizard is getting oxygen from the recycled air.

Many species of anoles, both on the main and on the islands, are semiaquatic; aquaticus occurs in Costa Rica and Panama, and the ones filmed were in southern Costa Rica. These semiaquatic anoles inhabit the vegetation alongside streams, and jump into the water when approached. As Lindsey notes, it is an effective anti-predator behavior. Many times I have seen anoles of these species flee from my approach into the water; I think I may once have seen aquaticus myself, in southern Costa Rica.

h/t: Matthew, Thom Sanger


Swierk, L. 2019. Anolis  aquaticus (= Norops aquaticus)  (Water Anole). Underwater breathing. Herpetological Review 50:134-135. pdf; jump to p. 27

The occasionally marine iguana

April 3, 2019 • 9:31 am

by Greg Mayer

Matthew sent me and Jerry this Tweet from PADI, of a wonderful video clip by Turtle & Ray Productions in Curaçao. It reminded Matthew of mosasaurs, an extinct group of giant marine lizards from the Mesozoic.

The common green iguana (Iguana iguana iguana) is widespread in Central and South America, and has also been introduced to a number of other places, including South Florida, where it is flourishing. It’s long been known that they readily take to water, both fresh and salt. I saw and photographed one in the harbor at Charlotte Amalie on St. Thomas in the Virgin Islands, but I’ve never gotten to see one from an underwater perspective! My friend and colleague James D. “Skip” Lazell, Jr., published this field sketch he made of a swimming iguana in his monograph on the genus Iguana in the West Indies. (This is Iguana delicatissima, a species endemic to the northern Lesser Antilles).

Field sketch by Skip Lazell of Iguana delicatissima swimming, Woodford Hill, Dominica (Lazell, 1973).

I immediately thought of the marine iguana, Amblyrhynchus cristatus, endemic to the Galapagos, where it lives along the coasts, and feeds on algae in the sea. Like the green iguana, in person I have only seen them from above the water. The following video, from Scuba Hank NYC, shows them underwater, both swimming and feeding. Upon seeing these lovely beasts lining the shores of the Galapagos, Darwin is said to have leaned over the the bow rail of the Beagle and exclaimed, “Wow, lizard city!

In looking for an appropriate marine iguana video, I came across this intriguing video, of a kayaker rescuing a green iguana four miles at sea off the Florida Keys. Besides being a wonderful story, and a testament to the kayaker’s humanity and, the iguana’s tenacity and ingenuity in figuring out that staying with the boat and jumping on, despite the presence of a man, was a good move, it helps to show how iguanas may have gotten to the Galapagos: they readily enter into, and can survive for some time, in the sea. Though not capable of directed swimming over great distances, this would make it more likely than landlubbing lizards that they could be carried off to a distant landfall, by what Darwin called “occasional means of transport.


Lazell, J.D. 1973. The lizard genus Iguana in the Lesser Antilles. Bulletin of the Museum of Comparative Zoology 145:1-28. BHL

Neill, W.T. 1958. The occurrence of amphibians and reptiles in saltwater areas, and a bibliography. Bulletin of Marine Science of the Gulf and Caribbean 8:1-97. pdf

That was not a 15-meter anaconda!

March 15, 2019 • 11:15 am

by Greg Mayer

So here’s the wrap-up on anacondas. First, as I mentioned in the previous anaconda post, alert readers went digging and found out the true story. Reader Roger first suggested it was stretched, and, following a suggestion by infiniteimprobablit, determined it was changed from an aspect ratio of .550 (typical, I think of cellphones) to 16:9; Michael Fisher located the original video. Here’s the original video:

There was also a discussion of the stretched video on reddit. The snake now looks like a typical anaconda: the stretched one made its color pattern look a bit odd, and appear to be very wide (which added to the impression of great size). After watching the original video, I sent the following message to Jerry:

It’s not fake, but it’s been stretched from a vertical cell phone video to fit a 16:9 format. I’ve now seen the original video. It’s crossing a road (not a stream), it’s not swimming, the guy filming is walking (not in a boat). It’s a big snake, but on the order of 5-7 m, not 15. Readers found this, and I’ll put it together into a post for tomorrow afternoon.

My guess on the conversion ratio was right, or close to it (see the detailed discussion by Michael Fisher and Roger on figuring out the exact method of aspect ratio conversion/stretching). The video was posted by the Youtube account of Dumato, a Swiss company with Brazilian roots. They said this about it in the video description:

Many thanks to Dinda from Manaus who took this video and sent to DUMATO, showing how Amazonia is alive and free

davelenny, judging by the ruts in the road, figured the snake to be less than 3 car widths long (which would be less than 18 ft. for a 6 ft. wide vehicle such as a Jeep or Land Rover. Michael Fisher, noting that the ruts are likely to be 60 inches apart, so that the road would have a width of 10 ft., suggests a total length of 12-15 ft. (ca. 4-5 m) for the snake. Jeeps/trucks have wider axles (65″ for a Toyota Land Cruiser), and the flooded section of the road where the snake is is a bit wider than the rest of the road, so I’d go a bit larger than Michael. My initial guess of 5-7 m is probably not way off, but I would lean more toward the lower end of that range.

Next, there’s the size of the anaconda on display at the San Diego Natural History Museum. It is about 22 feet, which I figured out by measuring the floor tile length using my feet (my feet, shod, are one foot long, as I’ve verified on many floor tiles and soccer fields), and then counting the number of floor tiles from one end of the snake to the other.

Anaconda on display at the San Diego Natural History Museum.

My hat, which placed in the picture for scale, is 7-8 inches across. Michael Fisher, using the hat, came up with 20 feet, which was the closest of any reader, and given the angle, a pretty good estimate. So, with a 20% stretch, the live length would be 18.3 feet, which is spuriously precise, so let’s say 18 feet.

And finally, as an extra added bonus, I need to point out that that’s not a shed skin; this is a shed skin:

Shed skin of ball python (Python regius), ca. 1.2 m total length.

Note that the shed skin is translucent and nearly patternless; it is also much lighter (in weight) than an actual skin, which is what is on display in San Diego. Shed skins are only rarely taken as specimens for museums, usually only to document very uncommon species or occurrences. The above is a shed from my ball python, Vyvyan. Below, you can see the skin between the scales. The scales are nearly transparent, but the skin between is more opaque; it is this opaque skin that gives a skin its “stretch”.

Shed skin of ball python (Python regius), ca. 1.2 m total length.

How big is this anaconda?

March 13, 2019 • 5:00 pm

by Greg Mayer

The anaconda in the video posted this morning is real, but it is certainly not 15 m long. Alert readers went digging, and found clues (posted in the comments) as to what the story is. I’ll post on that later, but for now, here’s another anaconda, this one a specimen I saw on display at the San Diego Natural History Museum. How big do you think it is?

Anaconda on display at the San Diego Natural History Museum, 16 January 2019.

This illustrates at least two phenomena, both of which have been problems in determining how big giant snakes can get: the difficulty of estimating size, and the effects of skin stretching. I’ll post my measurement of this snake along with the reveal on the “15 m” one later.

A 15-meter anaconda?

March 13, 2019 • 11:15 am

by Greg Mayer

Matthew Cobb sent me and Jerry a Tweet that contained this video, purportedly showing a 15 meter long anaconda (Eunectes murinus) in Brazil. Commenters on YouTube suggest it’s a fake, but I see nothing to indicate that. My Portuguese is very poor: I can hear the narrator say “cobra” (=snake), “anaconda”, and “sucuri”– this last is similar to a Brazilian Portuguese word I know, “sucuriju”, which means, at least roughly, “boa”, and is used in the combination “sucuriju gigante” for really big anacondas. Perhaps a Lusitanophone reader will favor us with a fuller translation. (“flurudha.com”, which appears at the lower right of the video, is a news-of-Albania-in-English site; I don’t know what’s up with that.)

It’s a big snake, but it’s hard to tell how big it is– there are no items of known size to compare it to. If the exact location could be determined, and the width of the stream measured, that could provide a basis for an estimate (although the shore is pretty featureless, and stream width could vary widely over time depending on seasonal rainfall patterns). There are many stories of huge anacondas. The account of Percy Fawcett, a British explorer is well known, having been featured in Bernard Heuvelmans’ work, and illustrated by his son, Brian; it was supposed to be 62 feet long.

From Heuvelmans (1959).

Heuvelmans also credulously records reports of 130 foot long anacondas, which he supposes might be an unknown species, distinct from the anaconda. But how big do anacondas actually get?

This question is intimately tied up with the question of how big reticulated pythons (Python reticulatus) get. The two species vie for the title of world’s largest snake: the anaconda is unquestionably heavier bodied than the slimmer reticulated python; but which gets longer? I’ve compiled a few judgments from the respectable literature immediately available to me.

Author Anaconda Reticulated Python
Barbour, 1926 14 m 32 ft. (29 ft. personally)
Ditmars, 1931 25 ft. (19 ft. personally) 33 ft. (24 ft. personally)
Ditmars & Crandall, 1947 26 ft. 33 ft.
Pope, 1955 30 ft. 32 ft.
Bridges, 1966 26 ft. (Bronx Zoo, ca. 1899)
Minton & Minton, 1973 38 ft. (Rondon; Lamon) 33 ft.
Ernst & Zug, 1996 11.5 m (Lamon) 10.1 m
Greene, 1997 10 m 10 m
Santora, 2002 26 ft. (Bronx Zoo, 2002)
Attenborough, 2008 7.5+ m 10 m
Pough et al., 2008 9 m
Vitt & Caldwell, 2009 8m, possibly 11.5 m 10 m

You can see that the authorities disagree, with reticulated pythons being generally credited with a length of 32-33 feet (= 10 m; the Bronx Zoo lengths are of specific animals, not the largest ever), while anacondas are either 30 feet (or less) or 11.5 m. Now there are several problems with knowing the maximum size of a species of large snake, beginning with the fact that the biggest snakes will probably be rare. But once you find one, how do you measure it? It is very hard to measure a live snake– I know from experience. They won’t sit still, keep curving, and might bite you. Now make its length more than 4 times your height! But if you collect the snake, the only practical way of preserving the specimen is as a skin, and skins notoriously stretch. A few cases of comparing the size of the snake and its skin have been reported, and the skin is about 20% longer than the snake.

Generally, claims about the size of animals are based on actual museum specimens, but for giant snakes these are only skins, which are unreliable due to stretching. If measured in the field and not collected, then it is the credibility of the informant that determines whether a record is accepted, since there is no specimen. The maximum size of the anaconda is generally seen to hinge on whether or not we accept the record of Robert Lamon, a petroleum geologist said to have measured one in Colombia that was 11.5 m long, and which was published by Emmet Reid Dunn in 1944, an eminent American herpetologist resident in Colombia at that time:

Mi amigo el señor Robert Lamon, geologo de la Richmond Oil Company, me ha dicho que mato y medio un ejemplar de once metros y medio en los Llanos. Tambien he oido hablar de ejemplares de 14 metros pero la aseveracion del señor Lamon no es de “segunda mano” sino directa y digna de credito. (Translation by GCM: “My friend Mr. Robert Lamon, geologist for the Richmond Oil Company, has told me of killing and measuring a specimen of eleven and a half meters in the Llanos. I have also heard talk of specimens of 14 meters, but the firm declaration of Mr. Lamon is not ‘second hand’, but first hand, and deserves to be accepted.”

A number of herpetologists have further investigated this case, most notably John Murphy and the late Robert Gilmore (the latter actually a mammalogist). Gilmore met Lamon, and corresponded with him in 1954, but Lamon could not recall what his measurement had been. He did attest that he told Dunn about it at the time, so that whatever Dunn had written down would be most reliable. He added the interesting detail that he measured the snake with a 4 m rod (not a steel tape, as some had added to the story). Later, in 1977, Gilmore met some other Colombian petroleum veterans, who cast some aspersions on Lamon’s credibility, but these aspersions must themselves have their credibility contested, being decades old recollections, not contemporary accounts. Gilmore and Murphy (1993) conclude that skepticism is warranted, and Murphy and Henderson (1997:45) explicitly say the measurement is “Probably in error”. We should always, of course, think it possible we may be mistaken, but I lean the other way, and my acceptance of the Lamon record is stronger now than it was yesterday, having investigated, probably as thoroughly as is still possible, the circumstances involved.

Sherman and Madge Minton (1973), besides Lamon’s anaconda, mention some other ca. 38 foot records of anacondas, records that have not been as thoroughly documented or investigated. One of them is attributed to Candido Rondon, the great Brazilian explorer and military officer, after whom the state of Rondonia is named, and who was the co-leader of Theodore Roosevelt’s last expedition (“The River of Doubt“). This seems, to me, to be a record worth pursuing– there is a likelihood that there may be substantial documentation concerning Rondon’s expeditions, as they were official expeditions undertaken as part of his military duties.

The Bronx Zoo for many years offered a reward for any snake 30 feet or more in length. Here is how late Curator of Reptiles John Behler put it in 1997:

The New York Zoological Society (i.e., the Wildlife Conservation Society) has offered a large reward for the live delivery of a 30-foot snake, in good health, to the Bronx Zoo since the days of President Teddy Roosevelt (1910). The reward offer currently stands at $50,000. Although there have been many inquiries and requests to finance giant snake expeditions (which we do not support), there have been no giant snakes presented for the reward.

The offer was terminated in 2002, when Samantha, the Zoo’s 26 foot long reticulated python died. (Further notes about her, including her capture, have been provided by a former keeper.)

Samantha the reticulated python at the Bronx Zoo. That’s John Behler on the far left. From the BBC, but a larger b&w version is in the NY Times notice of Samantha’s death.

Reticulated pythons regularly get longer than anacondas, as captive retics in the 25-29 foot range are not uncommonly reported, but I’ve not carefully investigated such claims. Guinness World Records lists a captive record of 25 feet 2 inches, but this is smaller than Samantha. Samantha’s last measurement was probably after her death, so would be a reliable measurement. The Guinness snake, named Medusa, was alive when measured, so might actually be longer, as it is hard to get the “kinks” out of a large snake for measuring, and these would make the measurement come out shorter than in a relaxed snake.

Medusa, Guinness’s record reticulated python. It is not in a zoo; I’m not sure what this place is.

Although wild anacondas are heavier bodied than pythons (and retics are especially slim), I’ve seen captive Indian/Burmese pythons which are long (in the teens of feet) and extremely obese, and which might well weigh more than anacondas of the same length.


Attenborough, D. 2008. Life in Cold Blood. Princeton University Press, Princeton, N.J.

Barbour, T. 1926. Reptiles and Amphibians: Their Habits and Adaptations. Houghton Mifflin, Boston.

Bridges, W. 1974. Gathering of Animals. Harper & Row, New York.

Ditmars, R. 1931. Snakes of the World. Macmillan, New York.

Ditmars, R.L. and L.S. Crandall. 1947. Guide to the New York Zoological Park. 5th, “Platypus”, ed. New York Zoological Society, New York.

Dunn, E. R. 1944. Los generos de anfibios y reptiles de Colombia, III. Tercera parte: Reptiles; orden de las serpientes. Caldasia 3:155-224.

Ernst, C.H. & G.R. Zug. 1996. Snakes in Question. Smithsonian Institution Press, Washington, DC.

Gilmore, R.M. and J.C. Murphy. 1993. On large anacondas, Eunectes murinus (Serpentes: Boidae), with special reference to the Dunn-Lamon record. Bulletin of the Chicago Herpetological Society 28:185-188.  pdf (Provides a good summary of the earlier literature, including important works which, because I did not have copies to hand, are not cited here.)

Greene, H.W. 1997. Snakes: The Evolution of Mystery in Nature. University of California Press, Berkeley

Heuvelmans, B. 1959. On the Track of Unknown Animals. Hill and Wang, New York.

Minton, S.A. & M.R. Minton. 1973. Giant Reptiles. Scribner’s, New York.

Murphy, J.C. and R.W. Henderson. 1997. Tales of Giant Snakes: A Historical Natural History of Anacondas and Pythons. Krieger, Malabar, Florida. full text

Pope, C.H. 1955. Reptiles of the World. Knopf, New York.

Santora, M. 2002. Never leather, Samantha the python dies at the Zoo. The New York Times, 22 November 2002, p. B3.

Hangin’ on in the wind: Natural selection, hurricanes, and lizards

July 27, 2018 • 2:10 pm

by Greg Mayer

Colin Donihue at the Anolis Symposium, 17 March 2018.

At the Anolis Symposium at Fairchild Tropical Botanic Garden in March, one of the stars of the show was Colin Donihue of Harvard University, who gave a talk on the effect of last fall’s Hurricane Irma on Anolis scriptus, the endemic (and only native) anole of the Turks and Caicos. Colin and collaborators had chanced to visit and measure the morphology of the lizards just before the hurricane struck, and were able to return within weeks to see what had happened.

And something had happened. After Irma, the lizards had bigger toepads, longer arms, and shorter hind legs. The first two changes made sense—bigger toepads and longer arms are known to increase clinging ability in anoles– but the third seemed contrary to the first two. Longer legs would help them cling to the vegetation, and thus prevent them from being blown against the rocks or out to sea– so why did the ones with shorter legs survive better?

It was Colin’s exploration of this last question that made his talk one of the hits of the Symposium. In order to see the effect of Irma on the lizards, they used a garden leaf blower to simulate high winds, and recorded it all on video!

The video above is from Nature (not what Colin showed us in March), where the paper by Colin and colleagues will soon appear (already available online; there’s also a nice account of the field work by Colin at his website). What they have surmised, based on their leaf blower experiments, is that the hind legs of the lizards, once they’ve lost their grip on a perch, act as ‘sails’, catching the wind, and thus carrying the poor lizard away. “Yarr, ’tis an ill wind that blows a man out to sea.

What surprised me was that the lizards held on to the last with their arms—I would have thought that they would grasp with all fours, and that the hind legs, having a greater toepad surface area, would give out last. Perhaps the wind caught their (larger) hind legs around the perch, and forced them off first, presaging the eventual cause of blowing away altogether. As expected during a round of directional selection, the variances of traits generally decreased. Also, the body condition of the lizards was good—they weren’t starving after the hurricane, supporting the idea that the differential mortality occurred at the time of the storm.

So, what we have here is a nice demonstration of natural selection, and a plausible, experimentally supported cause of the differential survival. But it is important to note that this is not a demonstration of evolution by natural selection, and the reason for that is interesting, and relates to the fact that evolutionary biologists use the term ‘natural selection’ in a number of contexts.

While natural selection is a major cause of evolution, as Fisher noted in the first sentence of his Genetical Theory of Natural Selection, “Natural Selection is not Evolution.” A short definition of natural selection, and one that I have used in classes and in print is that natural selection is “consistent differential survival and reproduction of heritable variants.” That this does not equate to evolution by natural selection can be readily seen in the case of heterozygote advantage, such as sickle cell hemoglobin in malarial environments. In such cases, the result of natural selection is that the genetic composition of the population doesn’t change—rather, it reaches an equilibrium, and stays there. There’s no evolution.

But there’s another sense in which natural selection does not imply evolution, and that is the sense used in quantitative genetics, and also very often in studies of changes in quantitative phenotypic traits (such as the study under discussion). Quantitative genetics derives from the work of plant and animal breeders (which was an important source of facts and inspiration for Darwin), and one of its key results has long been summarized  in the ‘breeder’s equation‘:

R=sh²; or

Response to selection is equal to the selection differential times the heritability ()

What this means is that the evolutionary change due to natural selection depends on both how much the selected organisms differ from the mean of the population (the selection differential), and what proportion of that difference is passed on the offspring (the heritability). The heritability is where genetics comes in—the variants that are hereditary have a (non-zero) heritability.

The structure of the breeder’s equation flows naturally from how breeders work. First, they pick an animal to breed from, based on its possession of desirable variation (e.g., having larger breast muscles than average for a turkey). Then, they breed it. Finally, they check to see how much of the desirable variation is present in the offspring. If the offspring are exactly like the parent in the selected trait (i.e. desirable), then heritability is 100% or 1.0. If the offspring have only half the desirable advantage of the parent (say, being 4 ozs. larger than average, as opposed to 8 ozs. larger in the selected parents), then the heritability is 50% or .5. So in these two cases, selection leads to evolution. So where’s the problem?

The problem, or rather conceptual subtlety, is that the heritability may be 0—the offspring of the selected parents may not differ at all from the general mean of the population. Thus we can have selection, but no response to selection, and thus no evolution. So, although natural selection is often defined as I did above (consistent differential survival and reproduction of heritable variants), it is often the case that we can measure the differential survival before we know whether or not the variation is hereditary. And that’s what the breeder’s equation captures—the two-step nature of differential first, inheritance second.

The same two-step sequence of observation often applies in nature as well as on the farm or in the lab, and thus, ‘natural selection’ is often used in the sense of the differential, with the heritability evaluated separately (as it usually must be, since the observation of a phenotypic difference does not generally imply anything, one way or the other, about heritability).

As regards the measurement of selection differentials, Colin’s study has the very nice feature that the measurements were taken within the same generation; i.e. no reproduction had occurred—the second set of measurements were taken on lizards that had lived through the hurricane. This allows them to exclude certain other possible explanations—e.g., phenotypic plasticity—for the change in average morphology. A similar advantage accrued to the classic studies of natural selection in Darwin’s finches by the Grants and their collaborators. The Grants had the additional advantage that their birds were individually marked, so that the individual identities of surviving birds were known; on the Turks and Caicos, the same generation of adult lizards was sampled before and after the hurricane, and some individuals might indeed have been measured both times, but as the lizards were unmarked, individuals cannot be followed over time.

The next step for Colin is to return to the Turks and Caicos, to see if the morphological shifts persist into the next generation, thus supporting that evolution by natural selection has occurred—i.e., that the offspring resemble the selected (=surviving) parents. This could be complicated by the fact that, with the selective environmental force (Irma) now gone, there may be directional natural selection back toward the previous trait means. Thus, measuring the persistence of the observed change may be confounded by further changes occurring. As in the Darwin’s finches studies, a multi-year approach is called for.

The lizard traits that were studied are likely to be at least moderately heritable, as morphological features such as these are usually found to be so. There have been few studies of heritability in anoles, and there have been conflicting results. Using common garden experiments, Shane Campbell-Staton has found that critical thermal maximum, a physiological trait, is heritable in Anolis carolinensis; but Mike Logan has recently reported that heritability was low for other thermally-related traits in Anolis sagrei. Studies of the heritability of morphological traits in anoles should be a fruitful area of inquiry. One advantage the Grants had is that, using the information on pedigrees provided by individual marking, they measured the heritabilities of a number of quantitative phenotypic traits in the populations of Darwin’s finches they have studied.


Campbell-Staton, S.C., S.V. Edwards, and J B. Losos. 2016.Climate-mediated adaptation after mainland colonization of an ancestrally subtropical island lizard, Anolis carolinensis. Journal of Evolutionary Biology 29:2168-2180. link  (links marked ‘link’ may not be to full text)

Donihue, C.M., A. Herrel, A.-C. Fabre, A. Kamath, A.J. Geneva, T.W. Schoener, J.J. Kolbe and J.B. Losos. 2018. Hurricane-induced selection on the morphology of an island lizard. Nature in press. link

Fisher, R.A. 1930. The Genetical Theory of Natural Selection. Oxford University Press, Oxford. full text

Grant, P.R. and B.R. Grant. 2014. 40 Years of Evolution: Darwin’s Finches on Daphne Major Island. Princeton University Press, Princeton, New Jersey.

Logan, M.L., J.D. Curlis, A.L. Gilbert, D.B. Miles, A.K. Chung, J.W. McGlothlin, and R.M. Cox. 2018. Thermal physiology and thermoregulatory behaviour exhibit low heritability despite genetic divergence between lizard populations. Proceedings of the Royal Society B 285 (1878): 20180697. link

Mayer, G.C. and C.L. Craig. 2013. Theory of evolution. pp. 392-400 in S.A. Levin, ed. Encyclopedia of Biodiversity, 2nd ed., volume 3, Academic Press, Waltham, Mass.