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

Surprise neighbor

Back in November, we told you about a new snake den in the Galiuro Mountains (Scenes from a new den). We have been monitoring that den with our timelapse cameras ever since. After a relatively quiet winter, activity is really picking up around here. Based on our fall observations, we knew that western diamond-backed rattlesnakes (Crotalus atrox), gila monsters (Heloderma suspectum), Sonoran whipsnakes (Coluber bilineatus), and patch-nosed snakes (Salvadora spp.) visit this den. So we weren't surprised to see this large guy exiting the den on 29 March:




The rattlesnakes have been pretty active at the den's entrance for the past few weeks, so we knew there were a couple male and female diamond-backeds inside. What we did not expect to see was this handsome fellow:



Yeah, that's an Arizona black rattlesnake (Crotalus cerberus). The other Arizona black rattlesnakes we're monitoring here are just emerging from their dens and none have moved away yet, so its highly unlikely this guy just showed up at this spot. He probably shared this den with the western diamond-backeds all winter. These species are not often found together and this may be the first observation of the two sharing a den. PLEASE let us know if we're wrong about that - hey, you can use our new facebook commenting feature below!

Not your classic Arizona black rattlesnake den :-)

Rattlesnake sociality exists, it's complex, and likely occurs in multiple species

Drs. Rulon W. Clark, William S. Brown, Randy Stechert, and Harry W. Greene [1] found cryptic sociality in timber rattlesnakes (Crotalus horridus). Timber rattlesnakes use communal winter dens and pregnant females aggregate together at rookeries to gestate their young. Clark and colleagues collected DNA samples from rattlesnakes to examine relatedness within these aggregations. While all individuals from the same den were not related, aggregations of juveniles of the same age group and pregnant females that shared rookeries were related.


An adult male with several female and juvenile Arizona black rattlesnakes basking just outside their den.

Timber and Arizona black rattlesnakes are similar in many aspects of their behavior. Arizona blacks also den communally, although this behavior is not restricted to the northern part of their range as it appears to be in timber rattlesnakes [1,2]. Some female Arizona blacks use rookeries at or near their dens, although many nest alone.

So, are aggregations of Arizona black rattlesnakes related? Or like timber rattlesnakes, perhaps only aggregations of pregnant females and juveniles are related. Or maybe aggregations of Arizona black rattlesnakes are just random groups of unrelated individuals. This is one our research topics, which you can read more about here. Hopefully we'll be able to answer the above questions over the next couple years.

1. Clark, R.W., W.S. Brown, R. Stechert, and H.W. Greene. Cryptic sociality in rattlesnakes (Crotalus horridus) detected by kinship analysis. Biology Letters rsbl20111217; published ahead of print February 22, 2012. doi:10.1098/rsbl.2011.1217
2. Brown, W.S. 1993. Biology, status, and management of the timber rattlesnake (Crotalus horridus): a guide for conservation. Herpetological Circular 22.