A large Blacktailed Rattlesnake from the southeastern corner of Arizona. These snakes can be beautiful – a high contrast black and yellow with rainbow iridescence in the sunlight.

A large Blacktailed Rattlesnake from the southeastern corner of Arizona. These snakes can be beautiful – a high contrast black and yellow with rainbow iridescence in the sunlight.
A Blacktailed Rattlesnake from central Arizona. These snakes are often a green shade, leading to misidentification as a Mojave Rattlesnake (which, ironically, are seldom green in many areas). These are large rattlesnakes that live in mountainous terrain, commonly seen by hikers but rarely by homeowners.
A young Blacktailed Rattlesnake breaking position to hide in rocks. We’d accidentally disturbed it by showing up, but it held this pose long enough for us to back off and get a few photos. This is in a remote canyon far from any road, and being bothered by people isn’t a regular thing for the snakes here.
A young Blacktailed Rattlesnake moving up from the rock wall where it lives to catch morning sun in southeastern Arizona. Structures like this provide a range of options, allowing the snake to very precisely control its temperature – warming when it needs to, and retreating to shade as the day gets hot.
A Blacktailed Rattlesnake from just north of Phoenix, found on a long night hike of remote desert canyons. These snakes specialize in mountainous, rocky habitat, and are almost never found in the flats unless moving between nearby hills. They’re large rattlesnakes and often seen by hikers and hunters.
I spotted this Northern Blacktailed Rattlesnake (Crotalus molossus molossus) resting about 4′ up in a tree on a hike in Yuma County, Arizona. Being up there can serve many purposes, from getting some cooler air on the belly to better hunting opportunities. This snake was likely hunting, waiting for one of the small birds and lizards common in the area to make its last mistake.
A Blacktailed Rattlesnake resting in the filtered light of a dense bush. This is one of many seen at a relatively densely populated den, at which we only found blacktails. Just down the hill, Western Diamondbacks also made an appearance. With some “up” left in the mountain and a change to more high elevation juniper habitat, we’re hoping for the addition of other rattlesnake species.
A Blacktailed Rattlesnake resting on a log at the base of a massive rock outcrop in the New Mexico bootheel. This was found late in the season, and the snake likely spends the winter in a crevice up above alongside several others.
A colorful Blacktailed Rattlesnake from the southeastern corner of Arizona.
I found this Blacktailed Rattlesnake with a few others hanging out around a winter den early in 2024. Unlike other rattlesnake overwintering sites in the area, this one does not seem to be shared with the other rattlesnake species that can be found there – just lots of blacktails.
Dens like this have been difficult to pinpoint in environments that are mostly open rock, but over time the specifics have become more apparent and sights like this come easier these days. I’m looking forward to a return visit this spring.