What the Provincial Snakes of Canada Should Be

This post will soon be available in Spanish!

In case, like many Americans, you need a map

Happy Canada Day! And indeed there is a lot to celebrate, in particular Canada's new liberal government and the positive effects it has had on science and the environment. Three summers ago, I wrote in two parts (I and II) about what the symbolic snakes of each of the US states should be, inspired by the witty and spot-on post 'The State Birds: What They SHOULD Be' from thebirdist.com. In response to a tweet from Canadian Field Naturalist, a journal that publishes ecology, behaviour, taxonomy, conservation, and other topics relevant to Canadian natural history, and because Canadian provinces also have various representative symbols (none reptilian, except for the feathered kind, which I might add are somewhat better chosen than those of the US states), this summer I decided to cover the US's northern neighbor as well. Does Canada even have any snakes, you might ask? In fact, Canada is home to 27 species of snake, which might surprise those of us who have grown up in regions farther south. That's enough for every province and territory to have two provincial snakes, with one left over, although the uneven geographic distribution of species precludes that, as we'll see. I followed the same "no duplication" rule as I did for the State Snakes, but I allowed snakes that had been used as U.S. State Snakes to be used again, because almost all of the species found in Canada had also been used for a U.S. state. Feel free to chime in with your opinion about what your favorite province's snake should be, if it differs from my choice.

1. Alberta. Prairie Rattlesnake (Crotalus viridis)

Prairie Rattlesnake (Crotalus viridis)

Alberta, well-known for its dinosaurs, also harbors a fairly substantial diversity of modern reptiles for a place with such long winters. Seven species of snake can be found in the province, but perhaps the most quintessential are Prairie Rattlesnakes. Prairie Rattlesnakes in Alberta occur in shortgrass prairies, dry grasslands, and sagebrush in the southeastern part of the province. At the northwestern edge of their range, Prairie Rattlesnakes in Alberta take 5-8 years to reach sexual maturity, and give birth to 4-12 live young, which are quite large (~11" long; compared to ~9" in the more southerly parts of their range). Females may remain with their young for up to 10 days after giving birth. Historically, Prairie Rattlesnakes were found as far west as Calgary and almost as far north as Red Deer, but the species has declined in many areas due to persecution and habitat loss. Venomous snakes are rarely very popular, but provincial symbol-hood might help establish rattlesnakes as wildlife to be valued rather than pests to be exterminated (and Alberta is already quite progressive about protecting its snakes).

2. British Columbia. Sharp-tailed Snake (Contia tenuis)

Sharp-tailed Snake (Contia tenuis)

BC might be my favorite province, principally because of the Nanaimo Bar, a three-layer no-bake dessert created in the eponymous coastal city of Nanaimo. I chose the Sharp-tailed Snake to represent BC because in some ways it resembles a reversed Nanaimo Bar—the dorsal coloration is similar to the graham-cracker-and-almond base, the color of the sides to the vanilla custard center (sort of), and the belly to the delectable chocolate-and-coconut topping. These snakes are found on Vancouver Island, the nearby Gulf Islands, and possibly on the adjacent mainland. These cute little snakes eat slugs, including the infamous banana slugs, which I bet don't taste anywhere near as good as Nanaimo Bars. Descriptions of Sharp-tailed Snakes were first published in 1852 (by herpetologists Spencer Fullerton Baird & Charles Frédéric Girard, who received collections made the decade before in the Puget Sound area), exactly 100 years before the first printed recipes featuring Nanaimo bar ingredients were published in the Women's Auxiliary to the Nanaimo Hospital Cookbook (although I'll admit that's a pretty tenuis connection).

3. Manitoba. Western Hog-nosed Snake (Heterodon nasicus)

Western Hog-nosed Snake (Heterodon nasicus)

Even though Manitoba is very well-known for its Narcisse Gartersnake Dens, it has greater snake diversity than several of the other provinces, for which the gartersnake must be reserved. Some of Manitoba's most interesting snakes are Western Hog-nosed Snakes, which are found in sandy areas in the southwestern part of the province. As with other snakes at the northern limits of their range, they have a short activity season—they mate in May and lay 5-12 eggs in late June or early July, which then hatch by August. A study of Western Hog-nosed Snakes in Spruce Woods Provincial Heritage Park, Manitoba, found that they emerge from their burrows on any day when they could achieve a body temperature of at least 29°C (84°F). Like gartersnakes (though not quite to the same extent), these snakes can achieve fairly high densities in certain areas, so I think they could be good candidates for expanding our knowledge of snake ecology and behavior in the wild into phylogenetically-uncharted territory, challenging the statement made by Rick Shine in 1987 that "It's a good thing you Yanks have garter snakes, or you wouldn't have anything to study."

4. Newfoundland & Labrador. Maritime Gartersnake (Thamnophis sirtalis pallidulus)

Maritime Gartersnake (Thamnophis sirtalis pallidulus)

Newfoundland and Labrador is the only Canadian province without any native snakes. However, in recent years southwestern Newfoundland in the vicinity of St. David's has apparently been colonized by Maritime Gartersnakes, a beautiful subspecies of Common Gartersnake. Although no genetic analyses have been performed, it's likely that this population was founded by individuals shipped across the Gulf of St. Lawrence in hay bales or other cargo from Québec, New Brunswick, Nova Scotia, or Prince Edward Island. A poll by the CBC revealed that 12% of respondents thought that the recent colonization was "actually kind of cool", whereas a discouraging 49% of respondents were "not happy about it at all". It's rumored that gartersnakes were purposefully but unsuccessfully released in the St. John's area in eastern Newfoundland decades ago, either by farmers hoping to control rat populations or by someone who brought them back from the mainland hoping to sell them as pets (though both scenarios are likely more urban legend than fact). A string of recent mild winters may have allowed the gartersnakes in western Newfoundland to persist, but the extent to which climate change will enable a Florida-pythons scenario writ-small in Newfoundland remains to be seen. At the very least, this could be a golden opportunity for snake biologists to study what happens when snakes enter an ecosystem from which they have been absent for thousands of years, a rare event even in an age of snake invasions.

5. New Brunswick. Smooth Greensnake (Opheodrys vernalis)

Smooth Greensnake (Opheodrys vernalis)

Soctsman Andrew Leith Adams was an army physician who served in India, Egypt, and Canada during the 1800s. He spent his spare time studying the natural history of these countries, about which he later wrote several books, including his 1873 Field and forest rambles, with notes and observations on the natural history of eastern Canada. In it, he wrote "The Reptiles of New Brunswick are neither numerous nor formidable.", which, compared with the snake fauna he doubtless experienced in Egypt and India, was certainly true. He mentioned several snake species, in particular noting that "One of our most common fangless snakes is the active little green species (C. vernalis)", using the C. to abbreviate the genus Coluber, which Linnaeus had used for practically all snakes except boas and rattlesnakes. This handsome species has also frequently gone by the binomial Liochlorophis vernalis, among a half-dozen other genera into which it has been placed over the years.

6. Northwest Territories. Red-sided Gartersnake (Thamnophis sirtalis parietalis)

Mating ball of Thamnophis sirtalis parietalis

Red-sided Gartersnakes are the only snakes found in the Northwest Territories, where they achieve high densities near Fort Smith between the southern shore of the Great Slave Lake and Wood Buffalo National Park. Because there are few suitable hibernacula, thousands of individuals share the same den. Long winters and short, cool summers have resulted in a mating system that is unusual among snakes, although it is also possibly the most well-known because it is easily studied. Upon emergence from the in mid-April, snakes spend 2-3 weeks hanging around the entrance, during which time males compete fiercely to mate with females, forming colossal "mating balls". They then migrate over 2.3 miles (3.75 km) to their summer marshland habitat, where they remain until late August, giving birth to litters of young that are relatively small in number (~12 vs. ~19 in Manitboa) and large in body size (191 mm SVL vs. 154 mm in Manitoba). Females in the NWT rarely give birth in two successive years, instead saving up energy from one year in order to reproduce the next. They also mature at larger body sizes (570 mm SVL vs. 527 mm in Manitboa) than snakes further south. I bent the rules a little here since both Newfoundland and the NWT have only T. sirtalis (they have different subspecies, and this species might be split up fairly soon). 

7. Nova Scotia. Ring-necked Snake (Diadophis punctatus)

Brown-morph and normal Diadophis punctatus from Nova Scotia
From Gilhen 2011

Ring-necked Snakes are cute little snakes that mostly eat invertebrates, although they have been known to snack on the occasional salamander. In Nova Scotia, they can be found almost throughout the province, and an unusual brown morph occurs, particularly on Big Tancook Island in Mahone Bay along the east coast. According to the notebooks of Harry Piers, an early 20th century naturalist, museum curator, and historian, ringnecks were known to the native Mi'kmaq People as “the worst snake, Um-taa-kum (k)”, although it's not clear why. One communal nest found under a boulder near McCabe Lake in Halifax County contained 117 eggs, which must have been laid by at last 15, and probably many more, females (clutch size ranges from one to eight).

8. Nunavut. Ellesmere Island erycine (Eocene boa)

Drawing of Ellesmere Island erycine vertebra
Dotted lines show best-guesses at broken-off parts
A. Dorsal and B. right lateral view
From Estes & Hutchison 1980

Unfortunately, there are no living wild snakes in Nunavut. Initially I was going to get around this by writing only about the true provinces, but then I found evidence that a 50-million-year-old fossil snake vertebrae was found on Ellesmere Island, above the Arctic Circle at about 78.5° north (find it here at the awesome new Paleobiology Database Navigator). This vertebra belonged to an undescribed species of boid snake probably related to rubber boas, and it was found in an Eocene fossil deposit that used to be a lush river delta and floodplain, with abundant swamps, alongside pike, bowfin, and gar, mud & softshell turtles, alligators, monitor lizards, giant salamanders, and even primates. The single bone is part of the collection of the Canadian Museum of Nature (specimen number 32403) and hasn't been assigned to a species or even a genus because it's broken. Paleontologists are fairly confident that it is an erycine boid based on comparisons made with a half-dozen other extinct genera that probably belong in this group. Recent phylogenies of booids elevate Erycinae to a family, but do not include extinct taxa, so it's difficult to say for sure how these snakes were related to each other and to living species.

9. Ontario. Eastern Foxsnake (Pantherophis vulpinus)

Eastern Foxsnake (Pantherophis vulpinus)

Ontario has more snake species to choose from than any other province, including seven that are found nowhere else in Canada. At the JMIH meeting in Reno last summer, I posed the question of which one best represented Ontario to herpetologist Jacqueline Litzgus, a native of Ontario and a professor at Laurentian University. She was unhesitant in recommending the Eastern Foxsnake, the only species of snake whose range is mostly in Canada (which perhaps makes it sort of a national snake as well, although the common gartersnake is found in more provinces). Foxsnakes are large constrictors that are closely related to cornsnakes and (slightly less closely) to ratsnakes. They probably recolonized northern North America more quickly after the retreat of the glaciers than most snakes because of their mobility and the flat terrain left behind in the midwest. We once thought that the two species had a disjunct range, with the western foxsnake (formerly P. vulpinus) being found in the USA between the Missouri River and Lake Michigan, separated by a foxsnake-less area in northeastern Indiana and the lower peninsula of Michigan from the eastern foxsnake (formerly P. gloydi), which was found south and east of Lake Huron in Ontario, Michigan, and Ohio. However, a 2011 study used evidence from a single mitochondrial gene to suggest that the Mississippi River seemed to be a more significant genetic barrier and that western foxsnakes east of the Big Muddy in Wisconsin and Illinois were more closely related to eastern foxsnakes than they were to western foxsnakes in Iowa and Minnesota. Because the type specimens for both former foxsnake species were within the eastern lineage, this species became P. vulpinus (the older name), P. gloydi disappeared, and the "new" western foxsnake was named P. ramspotti. Runner up: Massasauga (Sistrurus catenatus), because of the town of Missisauga, Ontario.

10. Prince Edward Island. Red-bellied Snake (Storeria occipitomaculata)

Red-bellied Snake (Storeria occipitomaculata)

Located in the Gulf of St. Lawrence, Prince Edward Island was formed as a sandstone peninsula 250-300 million years ago. The end of the ice age 15,000 years ago and the retreat of the glaciers laid down glacial till and increased the sea level, disconnecting PEI from the mainland. PEI only has three species of snakes, all of which colonized the island within the last 15,000 years. Despite the fact that no lizards or turtles have been able to make the same crossing, PEI is still way ahead of Québec's similarly-sized Île d'Anticosti, which lies ~190 miles (~300 km) to the north and has no native species of amphibians or reptiles. Of the tiny red-bellied snake, PEI naturalist John Mellish wrote in the 1870s "This variety is numerous, is smaller in size, and seems to be less courageous than some of the other species". Although Mellish got this much right, he was as prone to exaggeration as many modern observers, interspersing his species accounts with tales of snakes charming their prey, swallowing their young, and attacking people. In reality, red-bellied snakes mostly attack slugs, and their peculiar lip-curling display is hardly threatening to a human.

11. Québec. Milksnake (Lampropeltis triangulum)

Milksnake (Lampropeltis triangulum)

Québec is best emblematized by the Milksnake, which was first described by a French herpetologist, Bernard Germain de Lacépède, in 1789. Lacépède's two-volume masterpiece, Histoire Naturelle, is a classic work in herpetology. Although Lacépède mostly used French vernacular names,  ("le triangle" for the milksnake, after the double triangles on top of its head), he used Linnaeus's Latin binomial system about 65% of the time in a 59-page table in the third section of the second volume, which covered legless amphibians and reptiles. However, because he was not consistent in his use of Latin binomials, the taxonomic community decided in 1987 that the names in volume two were not valid (volume one, which covers turtles, lizards, and amphibians, contains a 3.5' x 1.75' fold-out table that was consistently binomial, so these names remain valid). Four snake names, including Lampropeltis triangulum, were rescued because of their long history of use. The other three (Agkistrodon piscivorus, Langaha madagascarensis, and Python reticulatus) were much longer-used than L. triangulum, which probably wouldn't have made the cut if not for an earlier decision by the ICZN as part of a case involving the mistaken identity of Linnaeus's scarletsnake (Cemophora coccinea) specimen and the name he gave it, Coluber doliatus, which was mistakenly used for the milksnake for over 150 years. The 1967 case invalidated doliatus and fixed triangulum as the specific epithet of the milksnake, which prevented it from later being invalidated with the rest of Lacépède's snake names. In this way the species is somewhat rebellious (in a nomenclatural sense), which I think would please many Québécois.

12. Saskatchewan. Gophersnake (Pituophis catenifer)

Gophersnake (Pituophis catenifer)

On the first page of one of my favorite novels, Farley Mowat's Owls in the Family, the author describes growing up in Saskatoon, Saskatchewan: "When you stepped off the end of the Railroad Bridge you stepped right onto the prairie and there you were—free as the gophers. Gophers were the commonest thing on the prairie. The little mounds of yellow dirt around their burrows were so thick, sometimes, it looked as if the fields had yellow measles." Although I like owls, these days I more often have another gopher predator in mind—the eponymous gophersnake (Pituophis catenifer), also less-aptly known as the bullsnake. These harmless creatures are often mistaken for rattlesnakes, because they have a superficially similar pattern (and they do rattle their tails, although they have no specialized noise-making structure). Confusion over the common name led Edward Abbey or one of his editors to include the scientific name of the eastern indigo snake (aka the blue gophersnake), Drymarchon corais couperi, for the bullsnake in the essay 'The Serpents of Paradise' in the 1968 edition of Desert Solitaire (although it is correct in 1988 edition).

13. Yukon. ?

I hope they find a snake

The Yukon Territory has no living snakes and no snake fossils (yet). This is actually quite ironic, because most living North American snakes crossed into our continent from Asia over the Bering Land Bridge, and some of them almost certainly slithered through what is today the Yukon. It is possible that somewhere in the southern Yukon exists a population of gartersnakes, which are found in the southern NWT and also possibly in the Alaskan panhandle. Three reliable sight records and one specimen (now lost) from remote areas along Taku & Stikine Rivers in Alaska give us hope, although unfortunately neither basin enters the Yukon. Other snake sightings of snakes from Alaska include odd T. sirtalis and T. ordinoides specimens from more urban areas, which almost certainly represent translocations (genetic evidence supports this in at least one case). T. sirtalis are found just 200 miles (320 km) south of the Yukon border in BC. It isn't completely crazy to imagine snakes living at such northerly latitudes; European Adders (Vipera berus) are found above the Arctic Circle in Scandinavia. If nothing else, gartersnakes from British Columbia will probably disperse there eventually if climate change keeps up with predictions.

ACKNOWLEDGMENTS

Thanks to Ben Lowe, David O'Connor, JD Willson, Todd Pierson, Andy Teucher, Michael, Gary Nafis, and Nick Scobel for the use of their photos, to Jackie Litzgus for helping me make the decision about Ontario, and to Gareth Hopkins for introducing me to Nanaimo bars.

REFERENCES

Manitoba Thamnophis on the side of a U-Haul truck

Anonymous. 1987. Opinion 1463. De Lacépède, 1788-1789, Histoire Naturelle des Serpens and later editions: rejected as a non-binominal work. Bulletin of Zoological Nomenclature 44:265-267 <link>

Baird, S.F. and C. Girard. 1852. Descriptions of new species of reptiles, collected by the U.S. exploring expedition under the command of Capt. Charles Wilkes, U.S.N. First part. - Including the species from the Western coast of America. Proceedings of the Academy of Natural Sciences of Philadelphia 6:174-177 <link>

Brongersma, L.D. 1972. On the “Histoire naturelle des Serpens” by de la Cépède, 1789 and 1790, with a request to reject this work as a whole, and with proposals to place seven names of snakes, being nomina oblita, on the Official index of rejected and invalid names in zoology, and to place three names of snakes on the Official list of specific names in zoology (Class Reptilia). Bulletin of Zoological Nomenclature 29:44-61 <link>

Crother, B.I., M.E. White, J.M. Savage, M.E. Eckstut, M.R. Graham, and D.W. Gardner. 2011. A reevaluation of the status of the Foxsnakes Pantherophis gloydi Conant and P. vulpinus Baird and Girard (Lepidosauria). ISRN Zoology 2011 <link>

Estes R, Howard Hutchison J, 1980. Eocene lower vertebrates from Ellesmere Island, Canadian Arctic Archipelago. Palaeogeography, Palaeoclimatology, Palaeoecology 30:325-347 <link>

Gilhen, J. 2011. The Brown Morph of the Northern Ringneck Snake, Diadophis punctatus edwardsii, on Big Tancook Island, Mahone Bay, Nova Scotia. The Canadian Field-Naturalist 125:69-71  <link>

Hodge, R.P. 1976. Amphibians and Reptiles in Alaska, the Yukon, and Northwest Territories. Alaska Northwest Pub. Co.

Larsen KW, Gregory PT, Antoniak R, 1993. Reproductive ecology of the Common Garter Snake Thamnophis sirtalis at the northern limit of its range. American Midland Naturalist 129:336-345 <link>

Leavesley, L.K. 1987. Natural history and thermal relations of the Western Hognose Snake (Heterodon nasicus nasicus) in southwestern Manitoba. MS thesis. University of Manitoba, Winnipeg, Manitoba.

Rossman, D.A., N.B. Ford, and R.A. Seigel. 1996. The Garter Snakes: Evolution and Ecology. University of Oklahoma Press, Norman, Oklahoma. (Shine quote opens chapter 4, page 55)

West, R.M., M.R. Dawson, and J.H. Hutchison. 1977. Fossils from the Paleogene Eureka Sound Formation, N.W.T., Canada; occurrence, climatic and paleogeographic implications. Milwaukee Public Museum Contributions in Biology and Geology 2:77-93.

Life is Short, but Snakes are Long by Andrew M. Durso is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

Snake poop and the adaptive ballast hypothesis

Click here to read this post in Spanish
Haga clic aquí para leer este blog en español

Alternate title suggested by David Steen: Why snakes might benefit from holding it 

Most people probably spend as little time as possible thinking about poop, especially snake poop. Some animals produce enormous amounts of poop, like dairy cows. Others make lots of little poops - up to 50 a day in small birds.  In contrast, snakes don't poop much at all. In fact, because they eat so infrequently, snakes probably poop the least often of almost any animal. Anyone who has kept a snake as a pet can tell you that a few days after they're fed, most snakes tend to poop once (often in their water bowls, for some annoying reason), and they might poop again within a few more days. Like bird poop, snake poop is made up of two parts - the brown stuff (the fecal fragment, aka the actual poop) and the white stuff (the uric acid fragment, aka the pee, in a solid form). Also like birds, most reptiles use uric acid rather than urea to excrete their excess nitrogen, which helps them conserve water.

A young Racer (Coluber constrictor) that has eaten a
Ring-necked Snake (Diadophis punctatus) nearly 92% its length

You wouldn't think there would be much that's interesting about snake poop, but to a snake biologist everything about snakes is interesting. In 2002, Harvey Lillywhite, Pierre de Delva, and Brice Noonan published a chapter in the book Biology of the Vipers that detailed their studies on snake poop. Their most amazing finding was that some snakes can go for a really, really long time without pooping. As in, over a year. It's not because they're constipated though - these long fecal retention periods have actually evolved for a purpose in snakes. Here's what happens: most snakes eat very large meals, and they eat them all in one piece. That means that when a snake eats a meal, its body mass can more than double all at once, and it can only digest that meal from the outside in, because it hasn't chewed or cut it up into small pieces to increase its surface area. Even for the insane digestive tract of a snake, this is an incredible feat.

And the python's small heart grew two sizes that day
Figure from Riquelme et al. 2011

A well-publicized series of studies by Steve Secor and Jared Diamond on snake digestion is more than fascinating enough to warrant some digression. They revealed that some snakes actually let their digestive tracts atrophy between meals, and rebuild them (and many of their other organs, including their hearts, which double in size) each time they eat. If that sounds strange, remember that some snakes only eat a few times a year, unlike we mammals who must eat every day. In one paper on the subject, the authors used an analogy with driving a car in normal traffic vs. stopping at a railroad crossing. It's fine to keep the engine running during a brief stop, but turning the engine off saves fuel while waiting for a train to pass. By shrinking their organs, snakes are saving energy during the long fasts between meals. The flexibility of their body temperature and fundamental differences in their mitochondria are two of the ways in which snakes are able to endure these extreme fluctuations in their metabolic rate. As their gut size and metabolic rate change, so does their ability to uptake nutrients, which brings us back to the production of poop.

Uromacer oxyrhynchus just can't hold it's poop

Poop is what's left behind after your gut has extracted all the nutrients it can from a meal. The ability of a snake's gut to extract nutrients from its prey can change a lot as the gut itself is rebuilt following a meal. Specifically, it is highest following feeding and tapers off as physiology and morphology return to their pre-feeding states. Normally, once food has been reduced to poop, it doesn't hang around for long. This is true in mammals and birds and in some snakes, including ratsnakes, which normally take about two days between eating and pooping. Even that's relatively long compared with we humans, who are clinically constipated after three days. Other relatively slender or arboreal snakes such as bush and tree vipers (3-7 days) and tree pythons (~6 days) poop fairly regularly, and fecal retention time is at a bird-like minimum of 23 hours in the slender Hispaniolan Pointed-nosed Snake (Uromacer oxyrhynchus). But in other snakes, particularly in heavy-bodied species of henophidians and especially in terrestrial vipers, poop stays in the hindgut for months, even when they are fed often. The maximum values recorded by Lillywhite for boas and pythons fed mice are impressive: 76 days in an Emerald Tree Boa (Corallus caninus), 174 days in a Burmese Python (Python molurus), and 386 days in a Blood Python (P. curtus). For vipers, the figures are just as astounding: 116 days for a Puff Adder (Bitis arietans) and 286 for a Rhinoceros Viper (B. nasicornis) are among the longest, although nothing holds a candle to the heavyweight champion: one Gaboon Viper (B. gabonica) in Lillywhite's dataset that didn't poop for 420 days!

A Burmese Python intestine before (top), two days
after (middle), and 10 days after (bottom) eating.
From Secor 2008

The intestine of a snake can hold a lot of poop. Lillywhite & colleagues measured this by pumping (dead) snake intestines full of saline and found that an average viper hindgut can hold about twice as much total volume as that of a ratsnake. The cumulative mass of the poop stored by the vipers in their study totaled between 5 and 20% of the total body mass of the snakes. In humans, this kind of thing would cause an awful, awful death (some say that's what happened to Elvis). Why did these snakes do this? Lillywhite and colleagues put forth what they called the adaptive ballast hypothesis to explain their observations. When I first heard about the adaptive ballast hypothesis, I actually thought it would be that snakes held onto their poop so that they could use it defensively, in case they needed it to spray onto their would-be assailants during some future predation attempt or capture by a herpetologist. But in fact, it goes something like this:

Poop from this African Rock Python's last meal might help anchor it
as it laboriously swallows this wildebeest

Clearly, being heavy is not advantageous for arboreal snakes, so they poop on a regular basis shortly after eating. In terrestrial snakes, however, a little extra weight can give a snake a distinct advantage in capturing and handling large, potentially dangerous prey. Stored feces contribute an easily-altered component to the body's mass, an inert ballast that, unlike muscle, requires no energy to maintain (so long as the animal is sitting still and doesn't have to drag it around, a perfect fit for the sedentary lifestyle of pythons and vipers - no word yet on fecal retention in the sluggish elephant trunksnakes). This extra mass is concentrated in the posterior of the body, where it presumably increases both the inertia of that region and its friction with the ground. Essentially, the humongous mass of poop could anchor the back end of the snake during a strike or while constricting. Although no one has explicitly tested this idea, it's compelling, because the same evolutionary pressures that caused pythons and vipers to have heavy bodies in the first place could be selecting for these long retention times if they help the snakes more easily obtain food. What's more, the snakes could jettison their ballast quickly if it became a liability, such as following a new meal, before undertaking a long-distance movement, upon becoming pregnant, or prior to hibernation, thereby reducing their body mass by as much as 20% at one go.

In addition to providing ballast, the long time the fecal material spends inside the intestine could potentially increase the absorption of nutrients and water, although it probably doesn't take many months before the snake has got all it can out of its old meals. Uric acid and feces are normally mixed in snakes with short passage times, but in heavy-bodied viperids, boids, and pythons, feces are usually more compact and are more separate from the uric acid.

Few people have looked very deeply into these patterns of defecation (perhaps few would want to), so a lot of questions remain: does more frequent activity induce premature defecation? Do drinking or skin shedding influence defecation patterns? Do these patterns hold up in the field? What other functions might snake poop have? One study showed that captive snakes pooped more quickly after their cages were cleaned, whereas control animals whose cages were merely rearranged did not, which suggests that snakes might be using their feces for marking...something (we really don't know what since they aren't generally thought of as territorial, although they are a whole lot more social than most give them credit for). The mysteries are many.

ACKNOWLEDGMENTS

Thanks to Pedro Rodriguez for allowing the use of his photograph.

REFERENCES

Castoe, T. A., Z. J. Jiang, W. Gu, Z. O. Wang, and D. D. Pollock. 2008. Adaptive evolution and functional redesign of core metabolic proteins in snakes. PLoS ONE 3:e2201 <link>

Chiszar, D., S. Wellborn, M. A. Wand, K. M. Scudder, and H. M. Smith. 1980. Investigatory behavior in snakes, II: Cage cleaning and the induction of defecation in snakes. Animal Learning & Behavior 8:505-510 <link>

Cundall, D. 2002. Envenomation strategies, head form, and feeding ecology in vipers. Pages 149-162 in G. W. Schuett, M. Höggren, M. E. Douglas, and H. W. Greene, editors. Biology of the Vipers. Eagle Mountain Publishers, Eagle Mountain, UT <link>

Lillywhite, H. B., P. de Delva, and B. P. Noonan. 2002. Patterns of gut passage time and the chronic retention of fecal mass in viperid snakes. Pages 497-506 in G. W. Schuett, M. Höggren, M. E. Douglas, and H. W. Greene, editors. Biology of the Vipers. Eagle Mountain Publishers, Eagle Mountain, UT <link>

Riquelme, C. A., J. A. Magida, B. C. Harrison, C. E. Wall, T. G. Marr, S. M. Secor, and L. A. Leinwand. 2011. Fatty acids identified in the Burmese Python promote beneficial cardiac growth. Science 334:528-531 <link>

Secor, S. M. and J. Diamond. 1998. A vertebrate model of extreme physiological regulation. Nature 395:659-662 <link>

Secor, S. M. and J. M. Diamond. 2000. Evolution of regulatory responses to feeding in snakes. Physiological and Biochemical Zoology 73:123-141 <link>

Secor, S. M. 2008. Digestive physiology of the Burmese Python: broad regulation of integrated performance. Journal of Experimental Biology 211:3767-3774 <link>

Life is Short, but Snakes are Long by Andrew M. Durso is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

What the State Snakes Should Be: Part II

Click here to read this post in Spanish!

Haga clic aquí para leer este blog en español!

Several weeks ago, I debuted Part I of 'What the State Snakes Should Be', inspired by 'The State Birds: What They SHOULD Be' from thebirdist.com. With apologies for the late follow-up (I've been on vacation), I now present...

Part II

26. Montana. Bullsnake (Pituophis catenifer)

Pituophis catenifer

These large, harmless, common snakes are known for their loud hiss, which they augment using a flap of skin on the end of their windpipe. They also rattle their tail against dry leaves in order to intimidate their would-be predators. Also known as gophersnakes or blowsnakes, they are commonly mistaken for rattlesnakes, which they superficially resemble. Bullsnakes are found throughout the plains of central and eastern Montana, as well as in the Bitterroot Valley of western Montana. Appropriate to Big Sky Country, bullsnakes are among the longest of North American snakes, reaching incredible lengths of 9 feet as adults! Radiotelemetry studies have found that individuals spend up to 90% of their time in underground burrows, so these snakes must be quite abundant in areas where they are frequently encountered.

27. Nebraska. Western Hog-nosed Snake (Heterodon nasicus)

Heterodon nasicus

I studied these snakes in Illinois for my Master's degree, but nowhere have I seen them so abundant as in the Nebraska sandhills. Western Hognoses love sand, in which they burrow and lay their eggs. They also frequently unearth the buried eggs of other species, including those of lizards and turtles. Like their eastern cousins, they also eat amphibians and possess elaborate anti-predator displays. These snakes are easily observed in open areas during the day by anyone willing to hike around the beautiful sandhills region of the Cornhusker State.

28. Nevada. Desert Nightsnake (Hypsiglena chlorophaea)

Hypsiglena chlorophaea

Known for its nightlife, the Silver State is well-represented by Nightsnakes, which are secretive residents of deserts throughout the west. Nightsnakes are nocturnal, as evidenced by their vertical pupils, and eat lizards and amphibians, as well as lizard and snake eggs on occasion. They are most active on moonless nights after rain. Few people will have seen a Nightsnake, but they occur throughout Nevada. I also heard that the Nevada Nightsnakes might be a competitive team against the Mississippi Mudsnakes this year.

29. New Hampshire. Eastern Hog-nosed Snake (Heterodon platirhinos)

Heterodon platirhinos (dark phase)

Eastern Hognoses are well known for their elaborate anti-predator behavior, which involves vomiting, defecating, and flipping over onto their backs. Research in the southern part of the Granite State has shown that prey likely limits their distribution in the northeast, as they are found on barrier islands with small amphibians but not those without. A recent radio-telemetry study at the New Boston Air Force Station revealed much about the habitat preferences of these snakes. Overall optimal habitat was identified as hemlock forests having continuous canopy and understory architecture interspersed with fine-scale openings, in close proximity to wetlands and with a high density of leaf litter, debris, and rocks as well as homogeneous surface temperatures within critical thermal limits. Eastern Hognoses mostly eat amphibians and occur in two color phases, dark and patterned.

30. New Jersey. Northern Pine Snake (Pituophis melanoleucus)

Pituophis melanoleucus

Much of the pioneering research on pinesnake biology has taken place in the New Jersey Pine Barrens. We know a lot about the surprisingly social lives of these large snakes - for instance, they communally bury their eggs in habitual spots used year after year by the same females. Pinesnakes prefer sandy, well-drained soils such as those in the the New Jersey Pinelands, which may provide residence for some of the largest populations of pinesnakes in the Northeast. Their reputation as ornery is mostly undeserved, much like that of their fellow Garden State residents (something I can admit despite having been born in neighboring New York).

31. New Mexico. New Mexico Blindsnake (Rena dissectus)

Rena dissectus

Having just been to New Mexico, I know first-hand that there are a lot of snakes there to choose from. In the interest of representing the widest range of phylogenetic diversity, I decided that the New Mexico Blindsnake should represent the state, in part because I was fortunate enough to find one while I was there (my first wild scolecophidian!) and in part because they can be found in only a few states in the US. These diminutive serpents eat ants and termites and burrow in loose soil. This species was discovered by E. D. Cope in 1896 along a road to a silver mine at Lake Valley, New Mexico. Runners up: Narrow-headed Gartersnake (Thamnophis rufipunctatus), Mexican Gartersnake (Thamnophis eques), Chihuahuan Nightsnake (Hypsiglena jani), New Mexico Ridge-nosed Rattlesnake (Crotalus willardi obscurus).

32. New York. Brownsnake (Storeria dekayi)

Storeria dekayi

You might think the Empire State would be better typified by a grander snake, but there are several good reasons that Brownsnakes are special to New Yorkers (or should be). The first specimen of a Brownsnake was collected in New York by Dr. James DeKay, a zoologist and author of the 1842-1844 book Zoology of New York. He found the snake while it was ""swimming across a large bay on the Northern coast of Long Island." John Holbrook, the father of North American herpetology, named the snake for DeKay, making it the only North American snake whose name is a double patronym (the genus Storeria being in honor of David Storer, a Massachusetts herpetologist; see Massachusetts).

33. North Carolina. Southern Hog-nosed Snake (Heterodon simus)

Heterodon simus

Southern Hog-nosed Snakes aren't doing too well throughout most of their range. Habitat destruction and degradation, fire ants, and mortality on roads are among their major threats. The Sandhills of North Carolina are their stronghold, and we'd like to keep it that way. The North Carolina Herp Society supports Project Simus, a non-profit research program with the goal of monitoring Southern Hognoses in NC and learning more about their biology through radio telemetry and other techniques. North Carolina recently named a State Frog, a State Salamander, and a State Marsupial, so a State Snake could be next! Runners up: Carolina Pygmy Rattlesnake (the beautiful red phase) or Outer Banks Kingsnake or Carolina Watersnake (both endemic subspecies found in the barrier islands).

34. North Dakota. Racer (Coluber constrictor)

Coluber constrictor

Racers are one of North America's most widespread snakes, found in every state except Alaska and Hawaii. They are highly variable in color, ranging from brown to black to green to blue. In North Dakota, they are greenish-blue to gray with a bright yellow belly and a white chin patch. They aren't called Racers for nothing: their speed is astounding and it is common to see these snakes for just a second or two as you walk through a grassland. Racers inhabit the sagebrush prairies of western North Dakota and are commonly found near sources of water. They have large eyes which aid them in their pursuit of their prey during the day. Young racers have a distinctive speckled pattern that slowly fades as they mature. Due to their widespread nature, this species might be a good candidate for a national snake as well.

35. Ohio: Kirtland's Snake (Clonophis kirtlandii)

Clonophis kirtlandii

These small and interesting snakes were originally slated for Indiana, until I learned that not only were many of the seminal studies of them carried out in the Buckeye State and that they are named for an Ohio politician, malacologist, and co-founder of the Cleveland Museum of Natural History, Jared Potter Kirtland. Kirtland's Snakes are found only in the midwest, where they inhabit crayfish burrows. Because of the intensive agriculture that dominates rural areas of Indiana and other midwestern states, some of the best known Kirtland's Snake populations are found in urban areas. Runners up: Lake Erie Watersnake (an endemic subspecies), Black Racer (actual State Reptile).

36. Oklahoma. Western Diamond-backed Rattlesnake (Crotalus atrox)

Crotalus atrox

Much maligned symbol of the west, Western Diamondbacks are in much better shape than their slightly larger eastern cousins, in spite of heavy collection in some areas for use in rattlesnake roundups (festivals with the express purpose of executing as many rattlesnakes as possible in the misguided belief that this somehow makes people in the surrounding area safer). Corporate sponsorship and economic contributions to local economies have helped these festivals persist in the Sooner State and others, much to the detriment of wild rattlesnake populations. In fact, Western Diamondbacks and other rattlesnakes are not nearly as dangerous as cars, cigarettes, dogs, or many other things that people willingly accept as part of their lives. Granted, if one bites you you'd best get to the emergency room sooner than later, but they hardly deserve their vicious reputation, and confer many benefits to those with whom they share the landscape, including pest control.

37. Oregon. Common Gartersnake (Thamnophis sirtalis)

Thamnophis sirtalis

Although these snakes can be found in every state except Arizona, Hawaii, and Alaska, I have never seen more beautiful Common Gartersnakes than those in Oregon. Add that to the incredible coevolutionary relationship between these snakes and their toxic newt prey discovered in Oregon, and you have a good recipe for a state snake. Common Gartersnakes are capable of resisting the neurotoxic effects of tetrodotoxin, which paralyzes the muscles and nerves of most other predators. More resistant gartersnakes live in areas where newts are more toxic, are more brightly colored, and crawl more slowly.

38. Pennsylvania. Eastern Wormsnake (Carphophis amoenus)

Carphophis amoenus

It's tempting to put this smallest eastern snake for Rhode Island, but because it was discovered in the Keystone State by the famous Philadelphian and entomologist Thomas Say in 1824, I think it's more apt for Pennsylvania. Say described its opalescent scales and called it "a very pretty and perfectly harmless serpent," noting that "it is found beneath stones and prostrate logs, but not very frequently." Wormsnakes eat invertebrates and so are beneficial to have in and around your garden. Runner-up: Narrow-headed Gartersnake (Thamnophis brachystoma), found almost exclusively in Pennsylvania.

39. Rhode Island. Ring-necked Snake (Diadophis punctatus)

Diadophis punctatus

At least in the east, these snakes are small, with gorgeous yellow color beneath marked with black spots. Farther west, they are orange or red instead. The yellow ring around the neck gives the species its name. Described by Linnaeus in the 11th edition of his Systema Naturae, it was one of the first species of North American snakes known to European biologists. Ringnecks are usually found close to water underneath rocks and logs, although they rarely swim. Rhode Islands's many historic stone walls are ideal habitat for this species. Eating salamanders and invertebrates, these snakes are harmless and beneficial. Don't miss the playoff game between the Rhode Island Ringnecks and the Nevada Nightsnakes!

40. South Carolina. Cornsnake (Pantherophis guttatus)

Pantherophis guttatus

The Cornsnakes of the famous Okeetee Club of southern SC are famed for their bright colors. Popular pets, these snakes have been bred in captivity to produce a variety of color morphs not found in the wild. Cornsnakes eat lizards and small mammals and are named for their highly contrasting ventral pattern, which resembles an ear of Indian corn. Carl Kauffeld first wrote of the Okeetee Club in his book Snakes and Snake Hunting, wherein he recounts several of his experiences trying to find cornsnakes in their natural habitats.

41. South Dakota. Prairie Rattlesnake (Crotalus viridis)

Crotalus viridis

These rattlesnakes are fairly common in the Great Plains of the central USA wherever rocky outcrops (including man-made ones such as railroad track beds) provide suitable hibernation sites. They are closely related to Western Rattlesnakes (see Wyoming), with which they shared a common ancestor about 9 million years ago. Following their rise, the rain shadow of the Rocky Mountains fell over central North America, causing a drying of the climate that led to the gradual replacement of open woodlands by prairie. Differentiation of the eastern form involved isolation plus adaptation to the expanding grasslands east of the Rocky Mountains. Today Prairie Rattlesnakes are common across the western two-thirds of South Dakota, where they prey heavily on rodents.

42. Tennessee. Rough Greensnake (Opheodrys aestivus)

Opheodrys aestivus

Rough Greensnakes are beautiful denizens of riparian woods throughout the Volunteer State. They were first recorded from "Carolina", which included Tennessee at the time. Also known as vine snakes, these arboreal, camouflaged snakes eat insects and spiders. Because they are so well-camouflaged, the best way to spot them is often at night using a flashlight. Difficult to keep in captivity, I would volunteer to study these any time, as they are among the most graceful and popular of snakes.

43. Texas. Gray-banded Kingsnake (Lampropeltis alterna)

Lampeopeltis alterna

Texas has 85 species of snakes, more than any other state. I thought that Texans would like to have the longest or largest snake for their state snake (they'd probably call it their national snake), but both, as well as the largest rattlesnake, are more iconic of other places. As such, they will have to do with one of the most beautiful and coveted, the Gray-banded Kingsnake. These secretive snakes are found only in dry, rocky areas of the Trans-Pecos and Chihuahuan regions of the state, where they are active at night. Although popular in the pet trade, very little is known about the ecology of these snakes in the wild. Much of their habitat is inaccessible, made more so by strict laws regulating the recreational pursuit of snakes (herping or snake-hunting) in the state of Texas. Runners-up: Speckled Racer (Drymobius margaritiferus), Concho Watersnake (Nerodia paucimaculata), Brazos Watersnake (Nerodia harteri), Texas Indigo Snake (Drymarchon corais).

44. Utah. Wandering Gartersnake (Thamnophis elegans)

Thamnophis elegans

Because I currently live in Utah, I can attest to the ubiquity of these snakes almost throughout the state. So named because of their propensity to stray far from water, Wandering Gartersnakes have something in common with the early Mormon settlers of the Beehive State, who emigrated from their original homeland in New York through the Midwest to eventually end up in what is today Utah. Wandering Gartersnakes eat fish, frogs, and small mammals, and lack the resistance of some of their congeners to newt toxin because they do not co-occur with newts over much of their range.

45. Vermont. Black Ratsnake (Pantherophis obsoletus)

Pantherophis obsoletus

Familiar to many in the eastern US, ratsnakes are on the ropes in Vermont. Records from the west-central part of the state date from recent decades, with possible isolated populations in other areas of the Green Mountain State (though these records could represent releases of captive animals). Ratsnakes have been designated a Species of Greatest Conservation Need in Vermont’s Wildlife Action Plan. Popular in captivity, we are just beginning to learn about the ecology of wild ratsnakes, which are highly accomplished climbers and important nest predators. Their communal nesting ecology at high latitudes and their intriguing foraging and social behaviors are likely just the tip of the iceberg.

46. Virginia. Smooth Earthsnake (Virginia valeriae)

Virginia valeriae

These small brown snakes come in two types, rough and smooth. The Rough Earthsnake (Virginia striatula) is found in the southeastern part of the state, whereas the more widespread Smooth Earthsnake (Virginia valeriae) is found across the eastern two-thirds, and also in isolated populations in the western tip. Virginia also shares with adjacent states an unusual population of Smooth Earthsnakes, called Mountain Earthsnakes (V. v. pulchra or, sometimes, simply V. pulchra), found in high-altitude glades in Highland County, Virginia, and adjacent WV, MD, and PA. Mountain Earthsnakes have scale characteristics intermediate between the other two, although they are more closely related to Smooth Earthsnakes.

47. Washington. Sharp-tailed Snake (Contia tenuis)

Contia tenuis

Sharp-tailed Snakes are small and locally common. They are named for the needle-like spine on the end of their tail, which nevertheless is not actually very sharp and with which they certainly cannot harm a human. This is a good snake to have around your garden, as they eat slugs and other invertebrates harmful to plants. Sharp-tails are mostly found in Oregon and California, but an isolated population occurs in central Washington, where dozens of individuals can sometimes be found together underneath cover objects. Sharp-tailed Snakes may turn out to be more widespread in Washington, especially since they were first discovered in 1852 by members of the U.S. Exploring Expedition near Puget Sound, a region from which no further specimens have been found. Perhaps state snakehood would promote further exploration.

48. West Virginia: Timber Rattlesnake (Crotalus horridus)

Crotalus horridus

Kudos to West Virginia for choosing a snake for their state reptile in real life! As a reward, they get to keep it. The Timber Rattlesnake isn't an inapt choice, as they are found in mountainous forests almost throughout the state, wherever suitable overwintering habitat exists. A recent analysis of the diet of Timber Rattlesnakes in the northeastern US suggested that they may help regulate tick populations through consumption of their mouse hosts, thereby probably reducing the risk of human exposure to Lyme disease and other tick-borne pathogens. Runner up: the other (Rough) Earthsnake (Virginia striatula).

49. Wisconsin. Butler's Gartersnake (Thamnophis butleri)

Thamnophis butleri

Butler's Gartersnakes are found in open-canopy wetlands in the southern Great Lakes region. In reality, enough Wisconsinites dislike Butler's Gartersnakes for getting in the way of development in the Milwaukee area that it's got about as much of a chance of getting chosen as the state snake as the Spotted Owl has of becoming the state bird of Oregon. However, efforts to manage and preserve the remaining habitat might just succeed, and could be significantly helped along by placing a little more value on these little snakes. In the land of visionary land manager Aldo Leopold, I agree with this One Wisconsin Now blogger that good stewardship should trump special interests when it comes to Butler's Gartersnakes.

50. Wyoming. Western Rattlesnake (Crotalus oreganus)

Crotalus oreganus

These relatively small rattlesnakes are fairly common in the arid west anywhere that rocky outcrops provide suitable hibernation sites. They are closely related to Prairie Rattlesnakes (see South Dakota). These two species shared a common ancestor about 9 million years ago, populations of which were separated by the rise of the Colorado Plateau during the Miocene epoch. Volcanic activity in the southern area of the plateau prevented contact between the two populations. Further differentiation of the western form into six subspecies involved adaptation to various cooler climates west of the Rocky Mountains. The subspecies that occurs in the Cowboy State today is the Faded Midget Rattlesnake, a diminutive snake with a somewhat subdued pattern.

Feel free to chime in with your opinion about what your state's snake should be, if it differs from mine. What do you think the National Snake would be, if the USA had one? Vote in the poll at the right, or share your opinion in the comments below. If you missed Part I, check it out!

ACKNOWLEDGMENTS

Thanks to Pierson Hill, Todd Pierson, JD Willson, Taylor Henry, Dan Johnson, James Turek, and Gary Nafis for use of their photographs.

Life is Short, but Snakes are Long by Andrew M. Durso is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.