Why Evolution is True is a blog written by Jerry Coyne, centered on evolution and biology but also dealing with diverse topics like politics, culture, and cats.
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.
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.
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.
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 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.
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.
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.
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.
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!
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 (h²)
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. Naturein 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.
World Snake Day was this past Monday, July 16, and I missed it! I didn’t find out till Tuesday, and so a little snake catch up today. I did in fact, have two snake encounters on Monday. First, with Vivian, my 20+ year old ball python (Python regius), whom I see almost every day. It was just a “Hi, how are ya”, since it wasn’t time for feeding, and her water bowl didn’t need refilling. Here’s Vivian at a reptile demonstration at an alumni event at the University of Wisconsin-Parkside a few years ago. Vivian often participates in such public events, and is usually the star of the show. Ball pythons are probably the best choice for a reptile pet.
Vivian, a ball python, at an alumni event, August 29, 2015.
I also checked in on Hissy, a bullsnake (Pituophis catenifer sayi), for my colleague Chris Noto. Bullsnakes do not make as good pets as ball pythons– Hissy is pretty ‘bitey’. The reason this one is kept is that it is an escaped captive that was recaught, and, though native to Wisconsin, the species is not from this area, and thus there was no known locality to which Hissy could be returned.
Hissy, a bullsnake.
As a parting tribute to World Snake Day, here’s Bill Haast, late director of the Miami Serpentarium. He was bitten by venomous snakes over 100 times, and had developed antibodies to a variety of venoms that enabled him to donate blood as a treatment to other snake-bite victims. Despite his many bites, he lived to be 100! I saw this near life-size photo of him in the Miami airport during a visit last March.
“William Haast with a cobra at the Miami Serpentarium, ca. 1965” (A similar photo in the NY Times obit is said to be from the 1950s.)
If you want to learn more about snakes, I recommend, as I have before, Harry Greene‘s Snakes: the Evolution of Mystery in Nature (U. Cal. Press, 1997) as a good, well-illustrated, introduction to their natural history and diversity.
A couple of Sundays ago, June 17, 2018, my wife and I took a paddle along the Root River, in Racine, WI. Starting out at the Root River Environmental Center (REC), we went upstream, around the island in Island Park, and back down to the REC. Along the way we saw quite a few turtles– 15-20, although at least a few were the same turtles seen going both up and back.
Here, a shelled reptile and a glorified reptile share a tree trunk in mid stream.
Female mallard and map turtle in Root River, Racine, WI, 17 June 2018.
On the next picture, it’s a bit of “spot the turtle”– the smaller one is inconspicuous. Both these two and the one in the previous picture appear to be map turtles (Graptemys). These turtles are typically more riverine than lacustrine, and thus might be expected in the river, except that the Root River is outside the range of map turtles, which occur in Illinois to the south and along the larger rivers of western Wisconsin. The map turtles of southeast Wisconsin are almost certainly introduced. What species they are is not clear to me. The species-level taxonomy of map turtles is not completely worked out, especially down South, where each river that drains into the Gulf of Mexico seems to have a more or less distinctive population of map turtles.
Two map turtles in Root River, Racine, WI, 17 June 2018.
Although it might be natural to think that one of the midwestern species was introduced into southeast Wisconsin, southern turtles can be found in the pet trade, and there may be more than one species present in the Root River. (In Kenosha, just south of Racine, I’ve seen at least two map turtle species.) It’s not known if they are breeding, and if so, whether different forms are crossing. I did find a hatchling in Kenosha, but I can’t rule out– in fact I lean toward– the possibility that it was released, rather than bred, there.
This next turtle is definitely a map turtle. Note the hint of serration or knobs on the shell along the midline, and the white neck markings.
Map turtle in Root River, Racine, WI, 17 June 2018.
The next turtle is a snapping turtle (Chelydra serpentina), hauled out on the island in Island Park. It’s not a very good picture– that’s its tail you’re looking at– as the turtle slipped into the water as we maneuvered for a better shot, but snapping turtles so rarely bask on land that I though it worth showing. (They often float right at the surface, which is their usual way of ‘basking’.)
Snapping turtle on island in Island Park, Root River, Racine, WI, 17 June 2018.
The species we saw the most of were midland painted turtles (Chrysemys picta marginata), which, like snapping turtles, are more of a pond than river species. The Root River is shallow and slow-moving, though, so the conditions are fairly pond-like. You can tell it’s the midland subspecies because the seams between the costal (‘rib’) scutes don’t line up with the seams between the vertebral scutes
Painted turtle in Root River, Racine, WI, 17 June 2018.
We saw a bunch, but the gal above let us get the closest, so she gets a closeup. (You can tell it’s a she by the large size and the short ‘fingernails’– males are smaller, and have longer front claws.)
Painted turtle in Root River, Racine, WI, 17 June 2018.
We did see two or three of southeast Wisconsin’s classic native river turtle, the smooth softshell (Apalone mutica). They are baskers, but very skittish, and thus hard to approach. I was using a 55-200 zoom lens on this trip, and got a decent picture of one. Notice that the ‘log’ it is on is actually an old piling or dock piece– note the bolt, nut, and metal plate.
Smooth softshell turtle in Root River, Racine, WI, 17 June 2018.
Finally, towards the end of our two-hour paddle, we encountered what I believe to be the same two map turtles we saw at the start of the trip, who are in the first picture above– it is the same log. Sexual size dimorphism is stronger in map turtles than painted turtles, so this could be a female and a male.
Two map turtles on the Root River, Racine, WI, 17 June 2018.
The possible male dove first, but we got close enough to see the neck markings and hint of dorsal serration in the probable female. Of the two native map turtles in western Wisconsin, the plain old map turtle, Graptemys geographica, is less serrated than the false map turtle, Graptemys pseudogeographica, so this would be a geographica, except that the two Wisconsin species aren’t the only possibilities. (One of the two map turtle species I’ve seen in Kenosha is definitely a ‘white-eyed’ southern form.)
A probable plain old map turtle on the Root River, Racine, WI, 17 June 2018.
Given that it’s a small river hemmed in by human development on all sides, with a past history of industrial usage, four species of turtle, all reasonably abundant– all with multiple sightings during the trip, except for the snapper, which, as a non-basker, is often not seen– is actually a decent amount of biodiversity.
I was not aware that yesterday was World Turtle Day. My only excuse is that I had spent the previous nine days in Costa Rica, and thus was largely out of touch with the Internet. (More on Costa Rica later.) So, a day late, here are my turtles.
First, here’s Slidey, a Red-eared Slider (Trachemys scripta elegans).
Slidey a Red-eared Slider.
This is a southern U.S. subspecies of a species complex widespread from the southeastern U.S. down into South America, and also found widely in the West Indies. This is one of the most popular turtles in the pet trade, and has become invasive in places. Even outside areas it can successfully reproduce, released individuals can survive. I have seen released/escaped individuals in New York, Maryland, and Wisconsin.
Here is me with Slidey (and also Toady, my Giant Toad [Bufo marinus]), at an eco-fair at Gateway Technical College in Racine, Wisconsin, in March, 2016. The theme of my exhibit was invasive species. (I also had a preserved lamprey, just barely visible in the jar below Slidey, and a small buckthorn which I had uprooted and brought in whole, whose branches can be seen sticking up above the Dell monitor. All these species are invasives which, at least in some places, have had negative consequences.)
Me, with Toady (a Bufo marinus) and Slidey.
Here is Snappy, a Snapping Turtle, (Chelydra serpentina), which is not an invasive species. It (or close relatives) is native from Canada down to northern South America.
Snappy, a Snapping Turtle.
And finally, not one of my turtles, but a Galapagos Tortoise from Charles Island.
