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!

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.

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 :-)

Drinking

Cap Mama takes advantage of some rain to take a drink of water dripping off the rock above.

Drinking is a behavior rarely seen in wild snakes. In fact, some would say that snakes don't need to drink. While it is rare to see this behavior, snakes do drink and likely need water in addition to what they acquire from their food. How important drinking is to snakes became very clear to me one day in March 2006 (Repp & Schuett 2008). Despite cold, rainy, windy, and even snowy weather, we saw more than a dozen western diamond-backed rattlesnakes drinking rain and snow outside their dens!

A poor quality video of rattlesnakes drinking snow during the long, dry winter of 2005-2006. Ugh - glad we have upgraded our cameras!

Last summer was pretty dry at our field site; the monsoon did not amount to much. In the photo at the top of this post, you can see Cap Mama snagging a drink about nine days after giving birth. The following videos were taken by our time-lapse cameras while the snakes were still pregnant:

This is Cap Mama again, about a week before she gave birth. Shortly after the rain starts, she emerges and drinks rain as it falls on her body.


Meanwhile on the other side of this rock outcrop, another pregnant female (Stache) also sneaks out for a drink. Unfortunately there is some grass in the way, but you can still get an idea of what a drinking snake looks like.

For more information on drinking and water harvesting in snakes, check out this paper:
Repp, R.A. & Schuett, G.W. 2008. Western diamond-backed rattlesnakes, Crotalus atrox (Serpentes: Viperidae), gain water by harvesting and drinking rain, sleet, and snow. Southwestern Naturalist 53: 108–114.

Scenes from a new den

We were recently told about a new social rattlesnake den in the Galiuro Mountains. We hiked in to check it out, saw one western diamond-backed rattlesnake (Crotalus atrox), and decided to set up one of our timelapse cameras. The video below is from the first two days of our monitoring, and we were a little surprised at all the activity:



That video is a little long and it’s easy to miss all the visitors, so here are stills of all the reptiles we spotted.






This is a juvenile Sonoran whipsnake (Coluber bilineatus). The closely related striped whipsnake (Coluber taeniatus) often shares dens with Arizona black rattlesnakes (Crotalus cerberus; see Are aggregations of Arizona black rattlesnakes stable and complex social groups?).







A gila monster (Heloderma suspectum)! It is not unusual for Gila monsters to share dens with western diamond-backed rattlesnakes and Sonoran Desert Tortoises (Gopherus morafkai). However, this Gila checks out the den only to turn around and leave. Could it be looking for a date? It's awfully late in the year for Gilas to be out and about.







Patch-nosed snake (Salvadora spp.) This is not a snake we have yet seen in any of our other dens. In this video, the patch-nosed appears to be checking the den out before moving on. Future videos may show if this snake continues to use the den.

There were a couple feathered reptiles here too (birds). Did we miss anyone? Who else will show up at the new den? Stay tuned...

Bandshell

Halfway between Tucson and Phoenix, a crumbling granite hillside gives way to a cactus-studded alluvial plain. Small, sandy washes break up this landscape and facilitate the growth of desert trees. Here, the western diamondbacked rattlesnake flourishes during times of plenty and, in leaner times, retreats to refuges to idle until conditions improve.

In February of 2010 we discovered a number of rocky refuges used by western diamondbacks to spend the winter. These sites are treasured by generations of snakes for the protection offered from freezing temperatures, an arrangement of safe basking locations, and, perhaps, a rock surface that funnels a sprinkle of rain into a drinkable collection.

In mid-February of 2011, we visited to this area again to find that snakes had returned to most of these sites. One spot, in particular, intrigued us. Whereas last year it was found to house but one snake, it now contained several, perhaps even five snakes. We call it Bandshell, and it’s a small eruption of rock from the hillside with a deep, nearly vertical crevice into an inverted rock face.

We mounted a timelapse camera near the face of Bandshell in hopes that we would see how many snakes used this den this winter and perhaps get a glimpse of some emergence (‘egress’) behavior. We were more successful than we could’ve imagined.

25 February – 2 March 2011

With the exception of a weak storm front moving through on the 27^th, the cameras record only a lack of activity by the snakes.

3 March 2011

Two young males, Scarecrow (S) and the Tin Woodsman (T) make their film debut.

These snakes engaged in combat, a ritualistic wrestling match whose outcome depends on which snake is better able to hold its opponent to the ground while intertwining. The victor may then be left to court a contested female.

Later that day, we return to swap data cards in the camera. About 5 m downslope of the den, we find T, stretched out amid brush and rocks. We are careful not to disturb him.

T enters the den at 1630, and S follows a quarter hour behind.

4 March 2011

A near repeat of yesterday. S slides out first with T following close behind.

This time, however, S appears reluctant to engage in combat.

T returns to the den at 12:48.

(Because of higher temporal resolution, the camera shuts off at 13:20 on 4 March)

6 March 2011

We arrive at 1000 and exchange memory cards. No snakes are evident outside the den.

T emerges and hangs around den.

S enters the den later that afternoon.

7 March 2011

Only T is active.

8 March 2011

T emerges, returns to the den, reemerges.

9 March 2011

No snake activity recorded.

10 March 2011

The warmest day so far this year brings some fresh characters.

The Cowardly Lion (C), a much larger male, emerges.

A female, Dorothy (D), emerges and coils at the entrance of the den.

T emerges and courts D. If you look carefully, courtship appears to continue just out of the frame in the upper left. At 1318, S emerges from the den, approaches the pair offscreen, and, apparently engages T in brief combat.

C crosses the frame.

T checks on the den.

C emerges from the den. S is not far behind.

T crosses the frame

A second female, Auntie Em (E), emerges.

We return to swap cards, but cannot do so without disturbing snakes around the den, so we postpone. E is still coiled at the entrance of the den.

S flanks the other side of the camera, about 2 m NE of the den entrance.

C returns to the frame to court E.

We return to find that S has vacated his post, and we take a chance on disturbing C and E, switching memory cards in the camera mostly hidden from their view. Although E is facing away, she appears to take a cue from C, who enters the den shortly after our departure.

About 20 m below the den, T sits in coil.

12 March 2011

The camera is now set to begin at 0800 rather than 0900, capturing the emergence of C.

E emerges and is soon joined by C.

At this point, the camera mysteriously shut off for 24 hours.

13 March 2011

E is visible coiled in the shade. C enters and courts her for 90 minutes, alternately chin rubbing and resting out of contact with her. Several times, as C rests, E moves her head slightly and appears to prompt him into another round of chin rubbing (e.g., at 14:58, 15:13, 15:28, 15:49).

14 March 2011

C is already out basking when the camera activates at 0800.

Later, T and one of the females emerge and interact. C returns, and the other snakes return to the den. C monitors then den, and at 09:53 E emerges, followed by T (10:05). E appears to be trying to re-enter the den as T vigorously courts her.

With E or T visible in the entrance to the den, C comes back and checks on the den several times., finally coiling in the shade to the left of the den entrance.

The next 90 minutes are obscured by the high contrast between areas in sun and shade, but at 12:24 the snakes are visible, with C out front, E (below) and T (above) in the den entrance.

15 March 2011

The only activity on this day is C posting up at the den entrance for a bit.

16 March 2011

Again, C is the only snake caught in the frame today as he checks on the den.

17 March 2011

A new snake, Oz (O) checks on the den. We think this snake overwintered at a different site.

18 March 2011

C checks on the den.

19 March 2011

Camera is taken down at 1000. Just a few meters downhill from the den, we discover E and C copulating.

Extra!! Click to see a passer-by...