Year of the snake (family)

As I reflected on my favorite snake moments of 2013, I realized we hadn’t shared the best story of all!

We added Luna and Cat to our study at Muleshoe in 2012 for one reason – we wanted to observe maternal care in Arizona black rattlesnakes at our new site. Despite all we’ve seen, mother rattlesnakes caring for their young is still the coolest. So we hoped these healthy female snakes would produce in 2013. Neither appeared to have given birth in 2012, so chances were good 2013 would be their year.

Cat was the biggest and oldest of the two, the most likely mother to be. But it was not to be. Cat entertained in other ways, kindly never strayed far from our backyard, and so we visited her almost every day. But no babies.

Cat, female Arizona black rattlesnake
Cat, female Arizona black rattlesnake

Luna started off the year acting as we expected a pregnant snake should. After emerging from her den, she moved a few meters and stayed put. This is the behavior we observed in pregnant Arizona black rattlesnakes we monitored in the past, so we were sure she was pregnant.

Then in early June she moved more than 300 yards – what?!? Pregnant snakes are not supposed to do that. She shed, made other little movements, but none of these sites looked like nests.

But Luna was getting fat. She seemed bigger everytime we saw her, so perhaps was pregnant. By mid-July Luna still hadn’t settled anywhere that looked like a nest, but she seemed to be way too big to move.

Luna, female Arizona black rattlesnake, looking very fat!

Then Luna disappeared. We were devastated. By this time we had already given up on Cat who was spending her days hunting. We looked and looked, but no Luna. We assumed her tiny transmitter’s battery had died early, because there was no way a snake that pregnant could have moved far enough for us to lose her.

We were wrong, and never happier to be wrong!

At the end of July we found (and by we, I mean Jeff) her a few meters off a popular hiking trail at the base of the hill where she overwintered. Then we lost her again (turns out she doesn’t have to move far in this terrain to lose us) and found her again (again Jeff) a few meters from her den.

Now this looked like a rattlesnake nest! So we set up a camera and waited for the magic to happen. Would we see behavior like we observed in our northern rattlesnakes? Or like many rattlesnakes in warm areas, would all the care happen in cover, out of site?


Luna at her nest site with one of her babies’ shed skin.

While Luna’s family didn’t spend as much time out as our northern Arizona black rattlesnakes, we got to see them do some cool things. And, as is often the case, we’re left with more questions than answers. We got a very different picture of Arizona black rattlesnake reproductive behavior using radio telemetry than we had with site-based observations – but we’ll save those thoughts for a later post.

For now, I want to leave you with a video of Luna’s family drinking together – two behaviors, rarely observed, filmed together. May 2014 bring many more happy snake stories!