A Herpetological Roundup

Turtle-headed Sea Snake (Emydocephalus annulatus), Okinawa, Japan, July 2011. Photo by Klaus Stiefel. Creative Commons Licence.
  1. The Christian Science Monitor reports on how the residents of the town of Glastonbury, Connecticut learned to live with—and help protect—the endangered Timber Rattlesnake (Crotalus horridus).
  2. When cicadas emerge, they’re a plentiful food source for many species—including, as the Houston Chronicle’s Shannon Tompkins learned, Copperheads (Agkistrodon contortrix), which aggregate in large numbers and stuff themselves silly.
  3. Pollution is turning sea snakes black. The Turtle-headed Sea Snake (Emydocephalus annulatus) normally has a banded pattern (see above), but individuals found in polluted waters around New Caledonia are increasingly melanistic. It’s a phenomenon called “industrial melanism”: melanin tends to bind to metal ions of trace elements like arsenic and zinc; melanism and an increased shed cycle allows these snakes to rid themselves of toxic metals. [Current Biology]
  4. Speaking of sea snakes, say hello to the Yellow Sea Snake (Hydrophis platurus xanthos), a newly discovered subspecies of the Yellow-bellied Sea Snake that is found in the warm, turbulent, anoxic waters of Golfo Dulce, off the Pacific coast of Costa Rica [Zoo Keys]
  5. When it comes to invasive reptiles in Florida, Burmese Pythons get all the press, but they’re not the only ones; CNAH lists 65 alien reptiles and amphibian species introduced to North America, most in Florida. Three of those species are chameleons. As invasive species go, they’re pretty innocuous, but still. National Geographic has a look at Florida’s chameleon hunters, who adopt out the chameleons they catch.
  6. Meanwhile, across the Straits of Florida, the Washington Post looks at an unlikely refuge for rare snakes like the Cuban Boa (Chilabothrus/Epicrates angulifer): Guantanamo Bay.
  7. A Manitoba couple caught a Plains Garter Snake (Thamnophis radix) in the act of gobbling down an Eastern Tiger Salamander (Ambystoma tigrinum). Small problem: the salamander’s endangered. That snake is in serious legal trouble.
  8. And what is almost certainly the weirdest reptile story ever to come to my attention: a story about turtle boners. No wait, it’s better than you think! It’s really difficult to figure out a turtle’s sex. So researchers came up with the idea of—oh boy—using a vibrator to stimulate the turtle: male turtles would get an erection. So: turtle boners. In the study, the method had a 100 percent accuracy rate. Because: turtle boners. Science is awesome. That is all. [Acta Herpetologica]

A Herpetological Roundup: World Snake Day Edition

It’s been a while since my last roundup, so there’s a lot to tell you about.

  1. Amphisbaenians—sometimes called worm lizards, though they’re neither, nor are they snakes—are the weirdest reptiles. And the mole lizards (Bipes) of Mexico, known locally as ajolotes, are the weirdest amphisbaenians, because while most amphisbaenians are legless, Bipes has forelimbs. Just forelimbs. You don’t see them very much because they’re so fossorial, but herpetologist Sara Ruane managed to catch one on video last month. Yes, it’s real. National Geographic has more.
  2. Speaking of legs, snakes still have the gene to grow them—the so-called “sonic hedgehog” gene. [Current Biology]
  3. It was long understood that snakes use the ZW sex chromosome system: the ovum determines the sex; males are ZZ, females ZW. Only a recent paper found that boa constrictors (Boa constrictor) and Indian rock pythons (Python molurus) have XY chromosomes—the sperm cell determines the sex, as it does in humans. [Current Biology]
  4. Ontario is extending Highway 400 toward Sudbury—through the territory of the threatened Eastern Massasauga Rattlesnake (Sistrurus catenatus). This CBC News article reports on the precautions taken by work crews as they work in massasauga habitat. Meanwhile, Lethbridge’s rattlesnake hotline—yes, they have a rattlesnake hotline—had a busy start to the summer.
  5. Turtle mortality along a stretch of road near Long Point, Ontario was so bad that local residents decided to do something about it. And after taking in nearly 600 injured turtles this year (up from fewer than 400 for all of 2016), the Ontario Turtle Conservation Centre, just outside Peterborough, has declared a “state of emergency” : they’re simply overwhelmed. Here’s a 2010 video from the Toronto Zoo showing how to help a snapping turtle cross the road.
  6. A turtle found wandering the streets of Burnaby, British Columbia turned out to be a threatened Wood Turtle (Glyptemys insculpta), which is not native to B.C. Showing signs of metabolic bone disease, the turtle was almost certainly an escaped or released pet kept illegally; it’ll be sent to a wildlife sanctuary in Ontario.
  7. The Guardian has the story of New Zealand’s cobble skink. The undescribed species was down to a few dozen individuals before wildlife officials tried to capture as many as they could before their habitat literally washed away. The entire population may now reside at the Auckland Zoo, awaiting reintroduction.
  8. Snake fungal disease has been found in more than 30 species in North America. Now it’s crossed the Atlantic: researchers have detected both the fungus and the lesions in wild snakes in both Great Britain and the Czech Republic. [Nature]
  9. Meanwhile, to prevent the spread of a fungal disease found in salamanders, the Canadian government has prohibited the importation of foreign salamanders, which will have an impact on the lab supply and pet trades. [Canada Gazette]
  10. In the Great Lakes region there are all-female populations of mole salamanders (Ambystoma) that are hybrids of several related species, e.g. the Blue-spotted (A. laterale), Small-mouthed (A. texanum) and Eastern Tiger (A. mavortium) Salamanders. A new study suggests that these female hybrids reproduce in a thoroughly curious manner: by mating with males from all three species, taking roughly equal parts of the donor males’ genetic material from each—a process called kleptogenesis. There are science fiction writers who’d have a hard time coming up with this. [Genome Biology and Evolution]
  11. Do snakes hunt in packs? A recent paper suggested that Cuban Boas (Chilabothrus/Epicrates angulifer) hunting bats in caves exhibit behaviour consistent with coordinated hunting. But David Steen is skeptical. “Snakes swallow whole. So when would ‘pack’ hunting be good? Only when there are lots of resources; no competition. Bat cave may qualify,” Steen adds on Twitter. [Animal Behavior and Cognition]
  12. Are snake bites on the rise? CNN’s alarmist headline and article gets smacked down.
  13. A question I answered on Quora: Why do snakes use constriction?

Snakes of the Eastern United States

The short version of this review: remember Snakes of the Southeast, the field guide by Whit Gibbons and Mike Dorcas, the second edition of which I reviewed last year and thought so highly of? Well, now Gibbons has done the same thing, only covering the entire eastern United States, with (appropriately enough) Snakes of the Eastern United States (University of Georgia Press, April 2017). Go get it.

But maybe I should expand on that a bit.

What impressed me about Snakes of the Southeast is that it knew its intended audience: not scholars, not hobbyists, but the general public. And in pitching itself at that audience, it knew what questions needed answering. As I said in my review last year:

The core of the book, the species guide, is detailed but plain-spoken, and does not drown the reader in scholarly references. It’s beautifully laid-out, with full-colour range maps and photographs of the region’s snakes. Its identification guide eschews the detailed scale counts used by professional herpetologists in favour of emphasizing distinctive traits and other factors more easily recognized by amateurs. And with two additional chapters explaining basic snake biology and exploring the relationship between snakes and humans, Snakes of the Southeast becomes a one-book solution: the book that tries to cover all the bases and answer all the questions about snakes that someone in the region might reasonably have.

Snakes of the Eastern United States follows that prescription down the line, which is no surprise given that it shares an author and a publisher with the previous book. The many virtues of Snakes of the Southeast, above and beyond being a species guide, are now accessible to people from outside that region. I’ve got a book I can recommend to more people.

In terms of its function as a species guide, as well as on field guides in general, though, I have a few thoughts.

Once again, this book takes an extremely conservative position on snake taxonomy. Rat snakes, for example, are called Pantherophis instead of the old Elaphe, but the traditional subspecies are maintained “because in most cases ratsnakes from particular geographic regions are easily identifiable based on color and pattern” (p. 198). Neither does Gibbons separate out the Common Kingsnake (Lampropeltis getula) into separate species, nor adopt the more recent taxonomic changes to swamp, crayfish and milk snakes. One gets the impression he sees these changes as for change’s sake.

Regional field guides have interesting edge cases, especially when they’re defined by political boundaries (a country, state or province) that don’t necessarily line up with bioregions: there’s always something atypical living in the borderlands. Gibbons defines the eastern United States as every state east of the Mississippi, excluding Minnesota but including Louisiana. So in this case we get central and western species like the Western Worm Snake (Carpophis vermis), Western Hognose Snake (Heterodon nasicus), Great Plains Rat Snake (Pantherophis emoryi) and Lined Snake (Tropidoclonium lineatum) at the edges of Gibbons’s maps. Illinois is usually the culprit.

(Speaking of maps: the map for the Butler’s Garter Snake [Thamnophis butleri] doesn’t include its Wisconsin range—a surprising omission given its politically charged status in that state.)

Then there’s the question of how the species are organized. This is actually an important consideration when the guide covers a large area or a large number of species. Some guides, simply list them in alphabetical order after sorting them by family (e.g. boas, colubrids, pit vipers) or separating the nonvenomous from the venomous snakes: this is the approach taken in Ernst and Ernst’s Snakes of the United States and Canada, Rossi and Rossi’s Snakes of the United States and Canada (no relation), and Werler and Dixon’s Texas Snakes. Others, like Alan Tennant in his state and regional field guides, categorize them in some fashion, e.g., small snakes versus aquatic snakes versus large terrestrial snakes.

Gibbons takes the latter approach, which necessitates some odd judgment calls, like splitting the kingsnakes between the midsize and large terrestrial snakes categories, or putting the closely related (and not that different in size) Short-headed Garter Snake (Thamnophis brachystoma) and Butler’s Garter Snake in the small and midsize categories, respectively. It’s the edge cases that’ll get you every time.

But these are quibbles, and there are always quibbles in books like these, which involve the compilation of a huge amount of field data, scientific knowledge, photography and text that must somehow come together in a whole that is not only coherent, but readable. This book achieves that end result far better than most.

I received an electronic review copy of this book via NetGalley.

Amazon

A Herpetological Roundup

Brown-snouted Blind Snake (Ramphotyphlops wiedii or nigriscens), November 13, 2015. Photo by Will Brown. Creative Commons Licence.
  1. Known from only a handful of specimens since its discovery in 1937 and feared extinct, the Albany Adder (Bitis albanica) was found alive and well—at least four specimens were—last November, in a South African location that is being kept secret to deter poachers. Because yes, poachers will collect the shit out of these snakes.
  2. The plan to reintroduce Timber Rattlesnakes (Crotalus horridus) to an island in the Quabbin Reservoir in Massachusetts has been suspended in the face of local opposition; the Worcester Telegram’s outdoors writer Mark Blazis is disappointed.
  3. Ontario Nature has announced its new and improved Ontario Reptile and Amphibian Atlas app, which isn’t so much an app as it is a mobile website that supports offline data. Anyway, it’s got a field guide and lets you enter species sightings.
  4. Fossil snakes are generally known from their vertebrae, which makes their study a little less exciting to the lay reader than dinosaurs; still, it’s rather exciting that a new extinct species, Zilantophis schuberti, has been described from a fossil found in eastern Tennessee. “Zilantophis bore uniquely broad wing-shaped projections on the sides of its vertebrae. In life, these were likely attachment sites for back muscles. These features are what inspired the name of the new genus, derived from Zilant, a winged serpent in Tatar mythology.” [Journal of Herpetology]
  5. Blind snakes (Scolecophidia) are tiny, secretive and easily overlooked; even so, there’s something of a blind snake renaissance going on, says Andrew Durso. “I recently noticed, much to my surprise, the the number of described species of blindsnakes has doubled in the last 13 years, from 305 in 2004 to 599 today; that’s 16.5% of all snakes! There are certainly many undiscovered species of blindsnakes, so it’s likely that their numbers will continue to grow.”
  6. A fascinating article in The New York Times Magazine from Daniel Engber that looks at the increasing use of the Burmese Python (Python molurus bivitattus) as a laboratory animal, and the possibility that its extraordinary digestive system—which has to flip from inactive to a 50,000-calorie meal all at once—may help find a cure for diabetes.

A Herpetological Roundup

Mating group of Red-sided Garter Snakes (Thamnophis sirtalis parietalis), Narcisse Snake Dens, May 5, 2014.
  1. Spring is here, and the garter snakes (Thamnophis) are busily mating away — and that means mating balls where as many as a hundred frenzied males may be trying to woo a single female snake. That frenzy may be harder on the males than the females: a new study found that telomere length — associated with stress — decreased with males as they aged, but did not do so with females. [Proc. R. Soc. B]
  2. Then again, it could be worse: a photographer caught a female Green Anaconda (Eunectes murinus) in the act of constricting and eating its mate.
  3. Speaking of constriction. Kingsnakes (Lampropeltis) are known for eating other snakes, and they’ve also been known to eat snakes longer than they are — including other constricting snakes. They do it by constricting harder — twice as hard as rat snakes. [Journal of Experimental Biology]
  4. Ontario has banned the hunting of Common Snapping Turtles (Chelydra serpentina), a species that had previously been regulated as game wildlife (with seasons and bag limits). Conservationists have long argued that any take is unsustainable, and they’re right: turtles simply reproduce too slowly, and face too many other dangers (roadkill, nest predation) — they’re simply in too much trouble already.
  5. In other good news, the Arizona snake shot — allowing snakes to be shot within city limits — bill died in a tie vote in the state senate.
  6. Researchers at Grand Valley State University are monitoring a population of Eastern Massasaugas (Sistrurus catenatus); they hope to learn more to fight the onslaught of snake fungal disease, which is hitting the massasauga particularly hard.
  7. Oh, great: the purported medicinal properties of the Indian Sand Boa (Eryx johniihas led to a spate of poaching and smuggling, putting the species, which is protected in India, at greater risk of extinction.
  8. India is also home to the unusual shield-tailed snakes (Uropeltidae), which Andrew Durso calls the “Darwin’s finches” of snakes.
  9. This January a rare species of boa, Corallus cropanii, endemic to Brazil’s São Paulo state, was found alive for the first time since it was described in 1953. It’s otherwise known from only a handful of specimens.
  10. Cobra venom is largely neurotoxic — it shuts down a prey animal’s autonomic nervous system — but some cobra venoms have cytotoxic, or tissue-destroying, qualities, most famously the venoms of African spitting cobras. Cytotoxins are painful but not as lethal as neurotoxins, so you’d think that cytotoxic venoms in cobras developed as a defense mechanism. But it turns out that cytotoxins don’t correlate with spitting, but with spectacular hoods: the more brightly banded or coloured a cobra species’ hood, the more cytotoxins in the venom. [Toxins]

It’s Simply the Wrong Time of Year for Unfertilized Corn Snake Eggs

So our 10-year-old female Okeetee corn snake, variously known as Little Miss Adorable, LMA and Ella Mae, started laying infertile eggs yesterday.

This is not unheard of — our female bullsnake, Lucy, and our leucistic Texas rat snake, Snowflake, have done this once or twice — so while we were surprised (February is really out of season for this sort of thing), we were not completely unprepared. Egg binding can be a thing, so we threw together a nesting box full of sphagnum and vermiculite, and then a larger box of sphagnum and vermiculite because her cagemate, Pretzel, wanted to curl up in there as well.

This does explain her recent behaviour: missing the last two or three meals (unheard of for a corn snake, except when gravid), restlessly pacing her cage and upending the furniture (much to the annoyance of Pretzel, who is twice her age and much more seclusive).

Five eggs so far, all infertile —  she’s never so much as shared a cage with a male snake, and for good reason: corn snakes are the second-friskiest snake species known to captive husbandry. This is much to the annoyance of the (aptly named) Trouser, the male corn snake who lives in the next cage, who I suspect has been slowly going nuts about living next to two female snakes for years. But when I kept Pretzel and Trouser in the same cage, she would hollow herself out laying eggs that turned out to be infertile. The only surefire way to keep corn snakes from breeding is to segregate them by sex.

All things considered, infertile eggs — or, in the case of live-bearing snakes like garter snakes, egg masses — are a pretty rare occurrence. Caught us off guard this time, it did.

Update, Feb. 17: As of yesterday, LMA has laid an additional six eggs, for a total of eleven. Her backside looks appropriately hollow and she’s entered her post-egg-laying shed cycle, so we can stand down with respect to the risk of egg binding. There’d been some worry about that for a while: at one point it looked like had an egg just above the vent that was not going to pass.

A Herpetological Roundup

Tuatara (Sphenodon punctatus), Willowbank Wildlife Reserve, New Zealand, Dec. 29, 2013. Photo by Flickr user _somaholiday. Creative Commons licence.
  1. Atlas Obscura on the comeback of the only remaining rhyncocephalian, the tuatara (Sphenodon). Breeding programs having more tuataras than they know what to do with is a nice problem to have. (I know people who, through zoo connections, have handled tuataras. I’ve never so much as seen one in the flesh.)
  2. Kenya has banned the export of various snakes, including the African Rock Python (Python sebae), due to the impact of collecting and poaching on wild populations. I would have thought that there wouldn’t be much demand, relatively speaking, for the large and nasty African Rock Python, but they’ve been collected so much that, like overfished species, their full-grown size in the wild has diminished. [via]
  3. A plan to reintroduce the Timber Rattlesnake (Crotalus horridus) to an island in the Quabbin Reservoir in Massachusetts is running into opposition from local residents, though the island is a more isolated and remote reintroduction site than just about any other alternative. [via]
  4. The discovery of a rattlesnake in a Texas home led to 23 more turning up in the cellar, where they’d been overwintering.
  5. Ceal Klingler writes about the time that a Panamint Rattlesnake (Crotalus stephensi) came by for a visit. [via]
  6. That Arizona bill allowing snakes to be shot within city limits — which I mentioned in my last roundup — has apparently passed.
  7. The Mexican Garter Snake (Thamnophis eques) is endangered in Arizona, so residents presumably still can’t shoot it. It was believed to have disappeared from the Colorado River system, but it was recently spotted near Lake Havasu City, which has wildlife officials scratching their heads a bit. [via]
  8. I knew about caudal luring — when a predator wiggles uses its tail (usually wiggling it) to attract prey — but this report of Puff Adders (Bitis arietans) using their tongues to do it is something else.
  9. Painted turtles (Chrysemys) don’t leave the water to hibernate, even when it freezes: they spend the winter under ice. How does that work? How do they breathe? The Nature Conservancy’s Cool Green Science blog explains.

A Herpetological Roundup

Gray Tree Frog (Dryophytes versicolor), Mansfield-et-Pontefract, Quebec, July 11, 2010.

Five things make a post:

  1. New tree frog genus. North American (and a few Asian) tree frogs previously included in the genus Hyla — including Gray and Green Tree Frogs — have been moved to a new, sister genus, Dryophytes, thanks to a major revision of tree frog taxonomy (PDF). This follows other moves to split genera that spanned continents: Bufo (toads), Rana (true frogs) and Elaphe (rat snakes) have all been split up; North American toads are now Anaxyrus, North American true frogs are now Lithobates (except on the Pacific coast), and North American rat snakes are now Pantherophis. So this is not really a surprise move.
  2. Water snake outreach. The Lake Erie Water Snake (Nerodia sipedon insularum) remains on Canada’s endangered species list, but it was removed from the U.S. list in 2011, after a rebound in its U.S. population, which now numbers 10,000 adults. An invasive fish, the round goby, has something to do with it: the water snakes happily feed on them. But public outreach played a role as well. On Cool Green Science, the Nature Conservancy’s blog, Ted Williams looks at the outreach efforts of Dr. Kristin Sanford, whose research showed that habitat loss was less of a factor than human persecution. Her (now quite dated) website: Respect the Snake.
  3. Don’t shoot snakes. An Arizona bill that would lift a ban on firing a gun within city limits if it’s to shoot a rat or a snake is facing opposition — from people opposed to shooting snakes.
  4. Do snakes fart? Scientists are building an animal fart database, and yes, snakes are included. While passing gas might not be a good sign for an obligate carnivore, if by fart we mean making noise while defecating, I can attest that snakes certainly do. (With some of my larger and stinkier charges, I usually hear it before I smell it — at least if I’m in the same room.)
  5. Stressed snakes strike first. A snake’s background level of stress — rather than the stress of encounter, handling or confinement — may determine how likely it is to strike, according to a new study. [LiveScience]

A Venomous Roundup

Black-tailed Rattlesnake (Crotalus molossus), Little Ray's Reptile Zoo, December 20, 2008.
Black-tailed Rattlesnake (Crotalus molossus), Little Ray’s Reptile Zoo, December 20, 2008.

Some links on venom, rattlesnakes, and rattlesnake venom:

  1. In April, BBC Earth explored venom overkill — why are jellyfish, snake and other creatures far more venomous than they need to be, especially given the metabolic cost of producing venom? The answer is deceptively simple: “[t]here’s no such thing as absolute toxicity” — venom is tailored to specific prey that may have evolved resistance to it.
  2. Most North American rattlesnake venom lacks neurotoxins, but a recent study finds that their common ancestor did have the genetic ability to produce neurotoxic venom 22 million years ago. That ability has since been lost to specialization (see above): Western and Eastern Diamondbacks lost the ability to produce neurotoxins about six million years ago; Mojave Rattlesnakes, whose venom is neurotoxic, lost a myotoxin gene about four million years ago. [Science News]
  3. A 36-year study of a population of Timber Rattlesnakes in the Adirondacks found that female rattlesnakes waited, on average, until they were 10 years old before having their first litter, and that most had only one litter in their whole lives. This has serious conservation implications. [via]

A Herpetological Roundup

Prairie Ring-necked Snake (Diadophis punctatus arnyi), Harding County, New Mexico. Photo by Andrew DuBois. CC Licence.
Prairie Ring-necked Snake (Diadophis punctatus arnyi), Harding County, New Mexico. Photo by Andrew DuBois. Creative Commons licence.

Five (relatively recent) things make a post:

  1. BBC Earth on snake fungal disease: “In a few species snake fungal disease is having a truly devastating impact. ‘The main species I look at is a rattlesnake called the eastern massasauga,’ says Allender. ‘They have a 92.5% mortality rate from the disease.’”
  2. Wildlife biologist Andrew DuBois takes great photos of wild North American reptiles and amphibians. See his Flickr and Instagram accounts. I’m fond of the garter snake shots, of course, but the species coverage in general is quite comprehensive. (Spadefoots! Ensatinas! Thread snakes!)
  3. On Quora I answered a rather dumb question: How would you defeat a large snake that decided to attack you? “The short version: I wouldn’t need to, and if I did need to, I wouldn’t be able to.” Read on for the long version.
  4. Maclean’s asks what’s killing the animals at Calgary Zoo — they’ve had a rash of sometimes-bizarre deaths, most recently seven penguins. But one stood out, at least to me: “one zookeeper resigned after starving a corn snake to death.” I have kept and raised dozens of corn snakes. They’re the easiest snake out there.  As I said on Twitter, “if a zoo can’t keep a CORN SNAKE alive — something 8-year-olds manage to do all the time — that’s a serious red flag.”
  5. Many snakes, including hognose snakes and European grass snakes, feign death as a defence mechanism. I didn’t know that indigo snakes did it too — at their size, I didn’t think they needed to.