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:

An Arizona Black Rattlesnake and Striped Whipsnake emerge from their den together to drink some rain.

At another den, we have seen Western Diamond-backed Rattlesnakes, Spiny Lizards, Gila Monsters, Coralsnakes, Western Patch-nosed Snakes, Earless Lizards,

Arizona Black Rattlesnake
Arizona Black Rattlesnakes,
Sonoran Whipsnake cruising by while an Arizona Black Rattlesnake sits at the right side of the den opening
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:

Gila Monster and Western Diamond-backed Rattlesnakes at their winter den.
Gila Monster and Western Diamond-backed Rattlesnakes at their winter den.

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.
An Arizona Black Rattlesnake (left) and a Madrean Alligator Lizard (right) rest outside a den.

Jaydin, a Western Black-tailed Rattlesnake we are radio-tracking, 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 and 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 Western 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.
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.
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. Pretty cool!