End Rattlesnake Republic Now!

A western diamond-backed rattlesnake (Crotalus atrox) with his mouth sewn shut for a rattlesnake roundup. Snakes are not under anesthesia during this painful procedure, but instead thrown in a freezer for awhile beforehand so they are too cold to move.  Photo by Kim LaForest, courtesy of RARR.

Rattlesnake roundups make me sick. What’s a rattlesnake roundup, you ask? This page has a more thorough description, but in short, they are festivals in which rattlesnakes are tortured and killed in the most inhumane ways imaginable for entertainment and profit. Where do they get hundreds to thousands of rattlesnakes for these events? They are abducted from their overwintering hibernacula (dens) in the spring and held for days to weeks without food and water. Yep, from dens – where snakes hang out with their friends, family, give birth, and take care of their and their neighbors’ kids.

What makes me REALLY angry is that Animal Planet has a show that glorifies the humans that collect rattlesnakes for these horrific events. Yep, Animal Planet. Does that make sense to you? If not, LET THEM KNOW. Animal Planet is soliciting comments about Rattlesnake Republic, probably because I and many others have expressed our disbelief and disappointment that they air this trash. Please visit their website and let them know (POLITELY) what you think about Animal Planet airing a show that glorifies the torturing and killing of animals for profit.

Here’s the comment I left on their site (feel free to use any of it!):

You state that “The series is intended to introduce the real individuals who choose to live among the dangerous world of rattlesnakes.” First, the world of rattlesnakes is only dangerous for rattlesnakes and their prey. Second, these individuals that exploit rattlesnakes for profit are hardly living in their world – they are removing rattlesnakes from their world and bringing them into the human world to be tortured and killed for entertainment (and nothing else).

There are many of us that really do live in the rattlesnakes’ world – we spend time in this beautiful and peaceful place so that we can know more about their lives and share that knowledge with others in order to promote the conservation of rattlesnakes. Why not have a series that introduces those individuals?

Most people view Animal Planet as an educational channel and Rattlesnake Republic teaches them that this misunderstood group of animals is dangerous and should be exploited for profit. Is that really the message Animal Planet wishes to send?

In the US, there are relatively few human bites from rattlesnakes (and most of those are to humans who chose to handle them) and almost no deaths. Here in Arizona, we have more rattlesnakes than any other state and roundups have been banned for more than 30 years, yet their numbers have never posed a danger to humans or other animals. There is no legitimate reason to ‘control’ rattlesnake populations, especially by these horrific roundups.

What rattlesnakes do need is some good PR for a change. Did you know that rattlesnakes are social? Rattlesnakes are choosy about which individuals they associate with and avoid others. Rattlesnakes give birth to live young and care for their kids for at least the first couple weeks of their lives. Sometimes they will take care of their neighbors’ kids as well.

This is the sort of information an animal lover would expect to see on Animal Planet, not the glorification of animal killers, which is what Rattlesnake Republic is all about.

Melissa Amarello
www.socialsnakes.org


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How can you cuddle without arms?

From the website "How can you cuddle without arms?"

I was contacted a while ago by a student in the Animal Behavior class at Reed College. For this class, pairs of students design a website on an animal behavior of their choice and this student was working on social snake behavior.

Check out their excellent website, "How can you cuddle without arms?".

What a fun and useful assignment! I am totally impressed with this class, but of course you'd expect great things from a class with this on their homepage:

Arizona black rattlesnake aggregations exhibit hallmarks of sociality

This summer we presented our preliminary findings on social snake behavior at the World Congress of Herpetology in Vancouver, British Columbia. Because our presentation was so well received (we won the Herpetologists' League Graduate Research Award!), we decided to adapt it for the blog. Enjoy! And we'd love to hear your feedback below, by email, or on Facebook.

When someone says social behavior, rattlesnakes are probably not the first animal that comes to mind. However, lizards exhibit a variety of complex, social interactions: stable family group-living, social and genetic monogamy, and cooperation (Chapple 2003, Davis et al. 2011, McAlpin et al. 2011).

Recently, Dr. Rulon Clark and colleagues documented cryptic sociality in rattlesnakes: pregnant female and juvenile timber rattlesnakes tend to aggregate with their kin. You can download and read the full article here.

We analyzed association patterns to describe social behavior of individual rattlesnakes. Specifically, we investigated two questions:

Gregariousness is an individual's propensity to be social.

Arizona black rattlesnakes (Crotalus cerberus) possess many traits linked to sociality: long lifespan, late maturation, and they care for their offspring. Important to this study, Arizona black rattlesnakes aggregate (group) at sites they use year after year (philopatric), are mainly diurnal, and phenotypically variable (individuals looked different).

We used remote timelapse cameras (Wingscapes Timelapse PlantCam and TimelapseCam 8.0) to record behavior of rattlesnakes within aggregations. We set up 1–3 cameras at each basking site, and they took photographs every 30 s from ~8am–6pm. We stitched these photographs into videos, which were lumped into day-long sampling periods.

Here we present results from one basking site (more to come from two additional sites!)

We primarily identified individual rattlesnakes using natural aberrancies in their dorsal patterns (see Zona's story for more information). When we captured rattlesnakes away from aggregation sites, we painted their rattles, which both assisted in identification and validated the pattern method.

This is an example of what our data look like, for one site on one day. Rattlesnakes observed within a body length were defined as in association; thus for rattlesnakes to be considered in association, we had to observe them together at least once during a particular day.

The next step was to take those observations of associated rattlesnakes and estimate the amount of time they spent together.

An association index (AI) estimates the amount of time each pair of rattlesnakes spent together. Because we were not always able to identify every individual in a group, we used the half-weight AI, which is less biased in these situations (Whitehead 2008, Cairns and Schwager 1987). The half-weight AI places more emphasis on the occasions when both animals are observed together than when one is observed without the other.

So now we have an estimate of the proportion of time each pair of rattlesnakes at this site spends together. We used the program SOCPROG to calculate AI's and test our research questions. Because AI's are not independent, SOCPROG implements a version of the permutation test developed by Manly (Bejder et al. 1998). This permutation test shuffled group membership within sampling periods (days) to produce a data set that represented what our data would have looked like if snakes were associating randomly. We then compared our observed data to the random data to see if rattlesnakes associated non-randomly.

Our measure of gregariousness was typical group size, or the mean group size experienced by an individual rattlesnake (Jarman 1974). We looked for differences in variation in typical group size (standard deviation = sd) between observed and randomly permutated data generated in SOCPROG.

Gregariousness varied among individual rattlesnakes; some rattlesnakes preferred to be alone or in small groups, while others preferred large groups.

Again, we are looking at variation in AI's between observed and random data. High variation in observed data, relative to random data, means that some pairs of rattlesnakes often associate (high AI) while others avoid each other (low AI).

Rattlesnakes are choosy about whom they do and do not associate with. At this site, observed variation in AI was significantly greater than random data overall and among female-female and female-juvenile pairs.

So YES - rattlesnakes are social. As mentioned above, we are currently analyzing data from two other basking sites and have a few more ideas to follow up this study:

We plan to use social network analysis to describe this population of rattlesnakes,

investigate how kinship affects association patterns,

and because we restricted our analyses to associations between Arizona black rattlesnakes as they emerged from their dens, we're interested in association patterns during the active season and in other rattlesnake species (left: black-tailed rattlesnakes in combat, Crotalus molossus; right: western diamond-backed rattlesnakes 'stacking', Crotalus atrox).

Our study describes social behavior in a 'non-social' species and may provide information on the evolution of sociality. But more importantly, our findings have the potential to impact conservation of an entire group of misunderstood and often maligned organisms. Humans have an innate fascination with snakes (Burghardt et al. 2009), but unfortunately, this keen emotional response is often appropriated by fear. Pernicious myths and popular media that have long portrayed snakes as malicious villains instill and nurture fear of snakes, which has led to widespread persecution and obstruction to conservation efforts (Seigel and Mullin 2009). In contrast to how snakes are usually seen in the media, recent research on rattlesnakes reveal behaviors that appeal to the general public: parental care (Greene et al. 2002, Amarello et al. 2011), cooperation, and social interactions (Clark et al. 2012, this study). By revealing the social nature of snakes, we are starting to change the public's perception of snakes from 'cold-blooded killer' to social creatures with complex family lives and make a positive impact on their conservation.

References and further reading

Amarello, M., J. J. Smith and J. Slone. 2011. Family values: Maternal care in rattlesnakes is more than mere attendance. Available from Nature Precedings.

Bejder, L., D. Fletcher and S. Brager. 1998. A method for testing association patterns of social animals. Animal behaviour 56:719-725.

Burghardt, G., J. Murphy, D. Chiszar and M. Hutchins. 2009. Combating ophiophobia: origins, treatment, education and conservation tools. Pp. 262-280 in S. J. Mullin and R. A. Seigel, eds. Snakes: ecology and conservation. Cornell University Press, Ithaca, NY, USA.

Cairns, S. J. and S. J. Schwager. 1987. A comparison of association indices. Animal Behaviour 35:1454-1469.

Chapple, D. G. 2003. Ecology, life-history, and behavior in the Australian Scincid genus Egernia, with comments on the evolution of complex sociality in lizards. Herpetological Monographs 17:145-180.

Clark, R. W., W. S. Brown, R. Stechert and H. W. Greene. 2012. Cryptic sociality in rattlesnakes (Crotalus horridus) detected by kinship analysis. Biology Letters, doi: 10.1098/rsbl.2011.1217.

Davis, A. R., A. Corl, Y. Surget-Groba and B. Sinervo. 2011. Convergent evolution of kin-based sociality in a lizard. Proceedings of the Royal Society B: Biological Sciences 278:1507-1514.

Greene, H. W., P. May, D. L. Hardy Sr., J. M. Sciturro and T. Farrell. 2002. Parental behavior by vipers. Pp. 179-205 in G. W. Schuett, M. Hoggren, M. E. Douglas, and H. W. Greene, eds. Biology of the vipers. Eagle Mountain Publishing, Eagle Mountain, Utah. USA.

Jarman, P. J. 1974. The social organisation of antelope in relation to their ecology. Behaviour 48:215-267.

McAlpin, S., P. Duckett and A. Stow. 2011. Lizards cooperatively tunnel to construct a long-term home for family members. PLoS ONE 6.

Seigel, R. A. and S. J. Mullin. 2009. Snake conservation, present and future. Pp. 281-290 in S. J. Mullin and R. A. Seigel, eds. Snakes: ecology and conservation. Cornell University Press, Ithaca, NY, USA.

Whitehead, H. 2008. Analyzing Animal Societies. University of Chicago, Chicago.

Interspecies interactions aplenty!

Friday evening while tracking Jaydin, we came across an Arizona black rattlesnake (Crotalus cerberus) hunting along an old corral fence.

BeeGee, male Arizona black rattlesnake, 17 August 2012 at 630pm.

BeeGee was still there the following morning, so we decided to put a camera on him.

While we have captured interactions between rattlesnake species and with squirrels before, it was pretty exciting to see both in one day!


What was going on between the Arizona black and western diamond-backed rattlesnakes? We don't know and would love to hear your thoughts in the comments below. For more information on squirrel - rattlesnake interactions, check out the work done by Rulon Clark's lab and his student Bree's blog.


In case the interspecies interactions weren't cool enough, BeeGee also demonstrated his species' ability to change color:

BeeGee, male Arizona black rattlesnake, 18 August 2012 at 9am.

Sharing

Ever since we saw Roger Repp's talk at the Tucson Herpetological Society, Burrow Buddies — or Not?, we've been fascinated by different reptile species sharing shelter sites. Multiple species often share the same overwintering site; we shared this fun example here back in April:

At one of our new dens at Muleshoe Ranch, we have seen western diamond-backed rattlesnakes, spiny lizards, Gila monsters, coral snakes, patch-nosed snakes, earless lizards,

Arizona black rattlesnakes,

and Sonoran whipsnakes (cruising by while an Arizona black rattlesnake sits at the right side of the den opening).

We've also seen western diamond-backed rattlesnakes and Gila monsters sharing den sites elsewhere:

And, lizards that would be prey for rattlesnakes during the active season also share den sites with their potential predators:

An Arizona black rattlesnake (left) and a Madrean alligator lizard (right) rest outside a den.

But what about during the active season?


There are probably chance encounters like this:

A black-tailed rattlesnake cruises by a resting Arizona black rattlesnake (Boyett).

Jaydin, a black-tailed rattlesnake we are radio-tracking at Muleshoe Ranch, spent a couple weeks shedding his skin in a particular rockpile earlier this summer. Last week we happened to be walking by that rockpile and even though we knew Jaydin was long gone, we looked underneath to see if anyone else was using it:

Sure enough, there was a juvenile western diamond-backed rattlesnake resting under the rock. For whatever reasons, these shelter sites serve the needs of different individuals of different species. In this case the visits by the black-tailed and western diamond-backed rattlesnakes were weeks apart, but what if they needed to use the rock at the same time?

A few days ago, a friend took us out to visit some rattlesnake nests. We stopped at a site that was being used this year by Sunny, a pregnant ridge-nosed rattlesnake, but found this little guy instead:

A juvenile rock rattlesnake prepares to shed his skin.

Where was Sunny? Did she move to a new nest site? Was she resting behind the rock rattlesnake? In more than 20 years of studying ridge-nosed and rock rattlesnakes, our friend has never seen them intermingle, despite the fact that these species are often found in the same habitat. After an unsuccessful check of other sites Sunny has used, we left to visit some other rattlesnake nests. We returned to Sunny's nest a while later and were greeted with this surprise:

A juvenile rock rattlesnake's head peeks out of Sunny's (pregnant ridge-nosed rattlesnake) coils.

Um, wow! What is going on here? Is this just coincidence or could they be interacting in a mutually beneficial way?

Through careful observation and using time-lapse cameras, we are seeing more examples of different species sharing sites. This is the first time we have heard of or seen two different snake species coiled together like this. If you have, we would love to hear about it in the comments section below - please share!

Red

Each summer, a friend of ours is visited by a male Arizona black rattlesnake whom she calls Red. Red spends much of the active season hunting near bird baths and feeders (or, in Arizona, 'snake feeders'), patiently coiled and awaiting an inattentive or distracted bird.

Usually Red turns up in late May, but with summer coming on and no sign of him, our friend was getting worried that a forest fire had been his end.

Just a week ago, our friend notified us of Red's arrival. And he's back in grand style!

Rattlesnakes are not known for their climbing abilities, but check out Red:

Red climbs higher and higher...


Red tops out on stretch of bare trunk (left) and starts back down (right).


Red slips safely off the tree.

Red gets up on some easy limbs, but you can see in the third picture that he has no way to get up the vertical trunk of the oak.

Why is Red climbing? Is he hunting? Rattlesnakes are classified as ambush hunters, meaning that they find a promising spot (as determined by scent and possibly, as in the case of an elevated bird bath, by sight) and sit and wait for their prey to come to them. Less often will rattlesnakes forage actively, i.e., crawl around looking for prey to eat. He may very well be after a meal up there!

While our friend hasn't seen any evidence of birds nesting in that tree, she has seen chipmunks using a hole near the top, so they may be nesting inside. Perhaps Red sensed the chipmunks and was trying to get them. If that is the case he is quite ambitious:

The red arrow points to the spot where Red climbed into the tree. The red circle shows the possible chipmunk nest.

Our friend was impressed by Red's grace off the ground. Although we have never seen an Arizona black rattlesnake climb higher that a downed log to hunt, we think, if a ladder of limbs permitted, Red would have gone all the way up.

Thanks to our friend for sharing the story and photos, and to Red for amazing us!

A tussle at the den?

I am currently reviewing all the footage from the dens this past spring and will have many things to share very soon (until then, you can see a new timelapse photo almost daily on our facebook page). Recently, I came across some rather unusual behavior:

What's unusual about this? Well, interactions among snakes at our dens usually look like this, where snakes just appear to be resting with each other:

So what's going on in the first video? We have never before seen any reproductive activity (male combat or males courting females) at our dens, but we think this might be combat. This timelapse video was taken at 30 second intervals, so much of the fighting action is lost. Also keep in mind, if you've never seen rattlesnakes fight, it's gentler than you might expect (not our video):

For years people thought that combat, or the so-called 'rattlesnake dance,' was courtship between males and females. Like many animals, rattlesnake combat is largely ritualistic and rarely involves biting. The goal is to topple your opponent, similar to professional wrestling (hence the twisting to be 'on top' in the above video).

For comparison, here's a male Arizona black rattlesnake courting a female:

So what do you think is going on in the timelapse video at the top of the page?

Bluffers & Cowards

Snakes are first cowards, then bluffers, and last of all warriors

(Pope, C.H. 1958. Snakes Alive and How They Live. Viking Press, New York, NY.) 

Yesterday morning Lula (our dog) and I headed back from tracking our rattlesnakes on a trail through the mesquite forest. Lula was only a step or two ahead, so I couldn't see the trail right in front of me. Mid-step, I saw a western diamond-backed rattlesnake (Crotalus atrox) stretched out across the trail where my foot was coming down. I immediately jumped back but Lula hadn't missed a step as she walked right over the snake. The snake reacted to my jump by assuming the defensive posture seen above and rattling.

Many believe that rattlesnakes spend their days waiting for a chance to 'attack' us, our children, and our pets. This rattlesnake had the perfect opportunity to attack us, but never attempted to bite. After a minute or two of rattling, it went back about its business:



Why? From a snake's perspective, we are the predator, the threat, and they are scared of us. A snake's first line of defense is to hope you don't see it (crypsis or camouflage), then attempt to escape (cowards) and/or display (for example rattling, bluffers). If given no other choice, they strike (warriors). And this is supported by numerous studies (for example: Gibbons & Dorcas 2002, Amarello et al. 2008), not just the anecdote presented here. Additionally,

“50 to 70% of reptile bites managed by the Arizona Poison and Drug Information Center were provoked by the person who was bitten--that is, someone was trying to kill, capture or harass the animal.” (Arizona Poison & Drug Information Center)

So perhaps we have something to learn from the snake: it is in everyone’s interest to leave each other alone.

Further reading:

Amarello, M., K. Bonine, and D. Lazcano. 2008. Factors influencing the antipredator behavior of Mexican lance-headed rattlesnakes (Crotalus polystictus) toward humans. Pp. 229-234 in W.K. Hayes, K.R.Beaman, M.D. Cardwell, and S.P. Bush (eds.), The Biology of Rattlesnakes. Loma Linda University Press, Loma Linda, CA.

Arizona Poison & Drug Information Center. Rattlesnakes (information on venomous snake bites in the USA).

Gibbons, J.W. and M.E. Dorcas. 2002. Defensive behavior of cottonmouths toward humans. Copeia 2002: 195-198.

Special, unofficial, guest blogger

Roger, adult male Arizona black rattlesnake named for Roger Repp (photo by Roger Repp).

We've been really lucky to have some fantastic volunteers at the site this spring (and also why I haven't had time to update the blog :-)).  One volunteer did his own write up of our adventures last weekend, which I highly recommend reading:

Serpent Research: Suzio Report, Off Plot Part 2

You can read more from Roger here

Big thanks to Marty Feldner, Roger Repp, and John Slone for your help!

Spring storm

This has been a strange spring here at the rattlesnake dens. It has either been unusually hot or like this:

14 April 2012

Last year, we saw a gradual increase in social basking behavior, followed by snakes dispersing for their summer hunting grounds. That process has been halted and restarted twice this year already! But, this site had a very dry monsoon season last summer, followed by a dry winter, so the precipitation is greatly needed here. And the snakes appreciate it as well, even if its accompanied by cold temperatures:

That morning our cameras caught several snakes drinking the rain, hail, and snow as it fell, but they quickly retreated deep into their dens again. There was little activity for the next few days and you can see why here:

More on snake activity later! We've seen so many familiar faces already...

Just for fun!

I'm hoping to have some current stuff to post soon, as the snake activity is really picking up right now, but I haven't had a chance to go through our photos and videos yet. So, here's a little something from last year, just for fun!

A cold storm brought some much needed precipitation (a mix of rain, snow, and hail) to our southern dens last April and an Arizona black rattlesnake (Crotalus cerberus) and striped whipsnake (Coluber taeniatus) took advantage of it to get a drink.

Teardrop & TIE Fighter

Awhile back we dedicated an entire post to the lucky or skillful young rattlesnakes that survived their first winter. In this population neonate (newborn) rattlesnakes have less than a month to find their first meal and locate a safe place to spend the winter. Of course it helps when your mom gives birth a couple yards away from her den (overwintering site), as Sigma did.

10 April 2012: Today we encountered two first year juveniles (rattlesnakes born last fall) near one of the dens, one basking and one hunting. They seemed very familiar, and sure enough, they are the son and daughter of Sigma, famous for her interactions with a squirrel.

Sigma and Teardrop, 6 September 2011.

Teardrop, 10 April 2012

TIE fighter, 6 September 2011.

TIE fighter, 10 April 2012.

Congratulations TIE fighter and Teardrop – you’ve cleared the first major hurdle of your life. We hope to see much more of you in the future.

Related posts:
Survivors
Sigma vs. the squirrel