Reptile Highlights of Southern California

By Daniella Rabaiotti


An adult common chuckwalla in the Indian Canyons, Palm Springs
Image copyright Daniella Rabaiotti

As a child I had always been fascinated by the BBC’s “The Natural World”. One of my particular favourites was an episode about the Grand Canyon, and I had been dying to visit California ever since. So I was chuffed when California was announced as the destination for the London NERC DTP field trip in 2015.

Most of the episode, as far as I remember (I was about 5 at the time), focussed on the unique reptiles of the region. Before we flew out, I did some research and found that two of the species featured – the common chuckwalla (Sauromalus ater) and the desert horned lizard (or horny toad, a great but somewhat misleading name; Phrynosoma platyrhinos) were present across a number of the sites we would be visiting. So as soon as we touched down in LA I was on the lookout for lizards, much to the chagrin of the geologically-oriented staff members.


A juvenile common chuckwalla in Joshua Tree National Park
Image copyright Daniella Rabaiotti

Chuckwallas are large rock-dwelling lizards that live across most of Southwestern USA and Mexico. They have a distinct head-bobbing behaviour that males used to warn off rivals, which is pretty comical to watch. I spotted my first chuckwalla – a big adult basking in the sun – just outside Palm Springs, down in one of the Indian Canyons. It was more impressive than I expected – it turns out a 14-inch lizard is actually pretty big. These sightings continued throughout the trip, particularly in Joshua Tree National Park, and other stops in the Mojave Desert. I also spotted a bunch of small yellow and black stripy lizards, which I was struggling to ID. Turns out they were baby chuckwallas, which change colour to the adults’ browny-orangey-blackish (technical term) appearance as they grow older.


A horned lizard in Joshua Tree National Park
Image copyright Daniella Rabaiotti

I found [definitely didn’t almost step on] my first horned lizard in Joshua Tree National Park. This species is pretty amazing – they are incredibly well camouflaged and very well adapted to desert living. If they are threatened, they puff themselves up and wave their enlarged body at you, making themselves as difficult as possible for predators to swallow. Some species, although unfortunately not the one I kept finding, even squirt blood from their eyes as a defence mechanism!


A desert tortoise in Rainbow Basin, Mojave desert.
Image copyright Daniella Rabaiotti

But by far the coolest species we came across was the desert tortoise (Gopherus agassizii), found exclusively in the Mojave Desert. They live at temperatures of over 60°C, and can dig basins in the soil to collect rainwater, a rare commodity in the desert. Unfortunately their numbers have declined by over 90% in some areas, making it an incredibly lucky wildlife sighting!

Note: if you ever find a desert tortoise – do not pick it up! They panic and wet themselves, and can die of dehydration as a result.

Twenty years on, California’s reptiles lived up to my childhood expectations (ok, bar the lack of blood squirting), and were definitely one of the highlights of an incredibly enjoyable trip.

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