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.

Savoie Acquitted in New Brunswick Python Case

Jean-Claude Savoie, the owner of the African Rock Python that killed two young boys as they slept in August 2013, has been found not guilty of criminal negligence causing death: Canadian Press, CBC News. The verdict comes after an eight-day trial that focused on a ventilation pipe the python escaped through, and whether Savoie was negligent in not securing it, or honestly believed the snake couldn’t squeeze through it.

New Brunswick Python Trial Begins

The trial of Jean-Claude Savoie, the former owner of an African Rock Python that escaped its enclosure and killed two young boys as they slept, begins today. The incident took place in August 2013 and was, to put it mildly, well-reported in the media (I even wrote an op-ed for the Ottawa Citizen about it.) Savoie was subsequently arrested and charged with criminal negligence causing death.

Hand-Feeding Wild Water Snakes

Tim Jones, a retired zoo director, has been hand-feeding the Diamond-backed Water Snakes (Nerodia rhombifer) that live in his private pond. The snakes have become so habituate to his presence that they’re comfortable taking food off his tongs. It doesn’t hurt that water snakes are rather food-motivated (which is a polite way of saying they’re extreme gluttons). You’ll note in the above video, along with shorter videos here and here, that they’re strongly directed by scent: if your fingers or pants smell like fish, it is by snake reasoning fish. Nom.

Now, Jones points out that this is a pond on private property; feeding wild animals is usually a no-no for very good reasons. You’d think that there would be little harm in habituating water snakes to human contact, or having them associate humans with food, and in a perfect world there wouldn’t be. It’s just that very few people would see an approaching water snake as friendly. Thwack. The end.

Some people might be surprised at the idea of tame water snakes, but I’m not. At one point, as some of you may remember, I kept three of them: two Banded Water Snakes (Nerodia fasciata) and a Northern Water Snake (N. sipedon), the latter under a provincial licence. They had insanely voracious appetites, but they were no less tame than any of my other snakes, and I put them to use in educational displays, where they wigged out people who believed water snakes were aggressive.

Basically, they’re just big garter snakes.

But mine were all born in captivity. That matters. It’s not reasonable to expect a wild animal to be friendly or tame: most will assume that a creature a hundred times their size is a threat to them. A snake has no idea that people are scared of it, or that being friendly and non-threatening toward people is a reasonable survival strategy. That’s counterintuitive.

Wild water snakes are bitey because they’re large enough for it to be a worthwhile defence strategy; smaller snakes of the same family, like brown and red-bellied snakes (Storeria), never bite, because there’s no point in doing so. Garter snakes are somewhere in between: some do, some don’t — it depends on the species, the individual and the circumstances.

Michigan Protects Five Reptiles and Amphibians

Michigan has added five reptiles and amphibians — Fowler’s toad, pickerel frog, mudpuppy, Butler’s garter snake and smooth green snake — to its animals of special concern list. The listing makes it illegal to kill or collect those species. That the Butler’s garter snake is included is significant: their lack of protection in Michigan meant that most specimens in captivity were originally collected there. (Mine certainly were.)