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]

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]