Rattlesnakes in a Heat Wave – What Homeowners Should Know About Snakes In The Summer

Each day in July, 2023 has been above 110˚F with no end in sight. What do the rattlesnakes do?

A common misconception is that reptiles love the sun – the hotter, the better, right? Well, not quite. Like all reptiles, rattlesnakes are ectotherms and get their heat from the environment. But that doesn’t mean they don’t have limits. Just like you in the office when whats-his-name down the row keeps fiddling with the thermostat, rattlesnakes prefer specific temperatures. And more importantly, they can quickly die when they get too hot.

How hot is too hot for a rattlesnake? It depends. Generally, if the body temperature gets above 110˚ for even a little while, a rattlesnake will not survive. With ground temperatures hot enough to cook an egg, a rattlesnake caught out in the open for even a minute mid-day in Arizona will not survive. Aside from overheating, prolonged heat can kill off rattlesnakes by desiccation, literally drying out in the Arizona oven while the monsoon takes its sweet time getting here.

Where do rattlesnakes go when so hot?

Rattlesnakes hide away during the hottest and driest time of year in carefully selected retreats in a behavioral state known as aestivation. Think of it as hibernation to escape the heat instead of cold. Each year, rattlesnakes may use the same aestivation den, alongside other rattlesnakes of multiple species. And just like hibernation, these aestivation dens serve as social hubs, as well as survival escapes.

In the wild, these aestivation dens may be a cave in a drainage wall, a deep crevice in a rocky outcrop, packrat nests, or any number of other deep, thermally protected areas. But near developed areas, an even greater resource exists: backyards.

Openings to the foundation, cracks in the concrete leading under the deck, the shaded base pad under pool pump equipment, and more can be ideal aestivation dens for groups of rattlesnakes. Even better, almost all backyards provide easy sources of water. Combine all of this with dense, well-watered lantana or rosemary, and the perfect rattlesnake summer sanctuary is made.

If you find a rattlesnake in the yard right now, it’s possible it has been there awhile.

These Speckled Rattlesnakes are resting a short distance from their aestivation den and will retreat once the sun heats the area. This is a similar situation to aestivation dens found at homes, where homeowners may encounter them on the patio a short distance from the actual den.

“But it’s a dry heat”

Don’t be fooled by this favorite statement of visitors from wetter climates. We’re not talking about feeling sweaty and uncomfortable while you eat BBQ – dry heat kills.

Moisture loss is a significant danger to rattlesnakes when it’s so hot and dry outside. Simply breathing is dangerous, as every molecule of water lost from the body won’t be replaced until it falls from the sky. Any source of sustained water can and will attract rattlesnakes and other wildlife. If there is deep cover nearby to wait out the day until the next opportunity to drink, it makes an irresistible resource.

A group of rattlesnakes I found living under a leaky AC unit behind our home.

For homeowners, now is the time to review the property. Something as simple as a dripping hose or irrigation line that’s a bit too generous may be an oasis bringing venomous snakes to the yard. Eliminate any sources of water possible. View the property as critical habitat, and make careful decisions. If a rattlesnake is spotted few times a year near that over-watered natal plum, it’s time for some hard decisions about that plant.

What happens to rattlesnakes that are relocated when it’s so hot?

This statement doesn’t exactly make us popular, but it’s the truth. Do not call the fire department or the local security guard to relocate snakes, especially when it’s this hot. Even if the fact the snake will likely die isn’t reason enough, a potentially more dangerous situation can be the result. It doesn’t matter who: call a professional with deep snake knowledge. Here is why:

Homeowners are finding rattlesnakes in entryways or in a corner along the back patio and calling for relocation. The trick is, however, that these situations are usually not new. If a rattlesnake is in a yard right now, there are two scenarios that are most likely:

  1. The rattlesnake has been aestivating on the property or immediately adjacent and is being discovered by chance after weeks of undetected behavior.
  2. The rattlesnake was displaced by construction. Or, with increased frequency, botched relocation by the fire department or under-experienced relocator.

Rattlesnakes are often found in small groups aestivating in backyards. When we are called to catch one, we can usually locate the aestivation den, where we look to see if there are more. The homeowner is then educated on what is happening, and how the den can be addressed to prevent future, similar encounters. In these instances, the snake itself is not the issue, but a symptom of a provided resource. Usually, these can be fixed relatively easily.

Rattlesnake encounters in the summer that are due to construction of unexperienced relocation are a more complicated matter, unfortunately. While it is a great thing that there is an increased will out there to not kill rattlesnakes and have them relocated instead, the details matter greatly. If a rattlesnake is captured by the fire department and moved to a nearby bush or released to open ground, one of two things happen: the snake dies, or it panics and manages to escape to the nearest cover. This can be shade at the neighbors’ house, back to the original location, or any number of potentially dangerous situations. Rattlesnakes that are able to behave naturally can often coexist for a lifetime without conflict with humans by careful evasion, but all bets are off when they are forced into a cover-or-die situation.

We are currently seeing a lot of activity on our snake removal hotline. Rattlesnakes and other wildlife are having a tough time in this heat, forcing them to take desperate measures to survive. This increase of conflict is something that can be resolved by working with the natural behavior of the snake. This means that snakes that are captured for relocation must be released directly into a suitable replacement aestivation den. This also means that the individual relocating the snake needs to be able to identify aestivation microhabitat.

Rattlesnake found while doing a snake removal

This Western Diamondback Rattlesnake was found by a snake relocator while searching for a suitable aestivation den to relocate a rattlesnake found at a home. This snake is a clue that the right release site is nearby. This careful release site selection is essential during the summer.

How to keep rattlesnakes out of the yard during the summer

The best way to keep snakes out of the yard during the hot, dry summer months is to reduce critical resources as much as possible. When it is this hot, rattlesnakes aren’t traveling around like they would be during the spring and fall, so the situations where they are found. This means rattlesnake encounters at homes are much more predictable and, therefore, avoidable.

Here are some things that can be done in a single weekend that can significantly reduce the chances of a summer rattlesnake den in the yard:

  1. Do a sweep of the property for unnecessary water sources. This means fixing the leaky hose, cleaning up the outdoor dog bowl area, and checking on landscaping irrigation and drip lines to make sure they’re in good shape.
  2. Watch areas of AC condenser run-off. You may be able to fix these situations by placing a metal can under them to prevent the ground from getting wet, and allow faster evaporation.
  3. It’s time to get rid of those overgrown, over-watered lantana and rosemary bushes. They come standard with every home in Arizona, but consider native plants that require less water and are less likely to attract rattlesnakes and their prey.
  4. Look into snake fencing as an option to physically prevent entry.
  5. Find and fill any cracks and openings to the foundation of the home and other buildings. Any access to crawl spaces, flashing, under pavement and the driveway, or the foundation can become rattlesnake dens in the summer.
  6. Carefully check seldom-visited sections of the yard: specifically pool pump areas and air conditioning units. These spots are usually hidden away and provide easy, private retreats for rattlesnakes and other animals.
  7. Flood and destroy rodent burrows as they are found.

By this time, when rattlesnakes have already been at their summer retreats for several weeks, it’s more productive to prepare for what comes next: the monsoon activity, where encounters will be at the highest rate of the year.

For more information about how you can make your yard less rattlesnake friendly, take a look at our guide to keeping rattlesnakes away.

What happens to rattlesnakes when the monsoon comes?

Once the monsoon rain comes, several events are kicked off.

First, the abundant ambient moisture and access to water relieve some of the survival pressure. Rattlesnakes will no longer be forced to hide away, meaning they can resume moving, hunting, and other activities. Rattlesnakes encountered in backyards will be less likely to be long-term residents. Aestivation dens are largely abandoned for the year for many species.

Often this is when rattlesnakes shed their skins, too. The moisture can start the shedding process, during which many rattlesnakes remain hidden away for a period of time, regardless of the nicer conditions outside. However, once they shed, they’re off to hunt and more.

Next, it’s time for babies! The moisture kicks off the birthing season. Rattlesnakes either birth in place, or move to special places where babies will be born, called rookeries. Depending on the species, the timing and location of this event varies. For Western Diamondback Rattlesnakes, which make up the bulk of rattlesnake encounters with homeowners, this can be about anywhere with adequate cover.


Questions and Answers about Summer Rattlesnake Activity:

Can I use a garden hose to move a rattlesnake away while it’s this hot?

You can, but it is likely a temporary solution. Rattlesnakes found in the yard right now are likely aestivating nearby, and will remain in the area until they can leave after the monsoon rain brings relief. Also, make sure the water isn’t too hot by spraying it to the side for a few seconds.

Are rattlesnakes more likely to be found indoors during this time?

Yes, but it’s still a very remote possibility. Even though indoors is obviously cooler, very few rattlesnake removal calls are inside homes during this time of year. The majority of rattlesnake in-home calls we respond to are due to doors being left open in the Spring and Fall, which is not an issue when it is above 110˚F outside.

Do rattlesnakes climb trees and shrubs to get away from the hot ground?

Rattlesnakes are often found up off the ground in bushes outside of their aestivation dens when it is this hot outside. A bit of airflow can help a snake keep cool, and they seem to take advantage of it.

How often do we find rattlesnakes that have died from the heat?

In our research of rattlesnakes living in urban islands, it is not uncommon to find rattlesnakes that have died during the hot and dry foresummer. This can be exacerbated by disturbance, such as stress from visitation or poorly performed relocation. An event as simple as a short delay from overnight location back to the den can mean death.

Am I attracting rattlesnakes if I provide water for generally preferable wildlife, such as rabbits and birds?

If this is being done in an area where rattlesnakes can occur: absolutely. Not only by providing water, but attracting prey animals as well. If there’s also an area the rattlesnakes can escape to during the day, it’s an ideal rattlesnake situation.

Where do wild rattlesnakes find water during the heat?

For the most part, they don’t. They are forced into a state of preservation, waiting for the monsoon rain to come. Others may find water at springs, rivers and streams, cattle tanks, and other sources of year-round water. But for many rattlesnakes, this simply isn’t an option.

Can excessive heat cause negatively affect the reproductive success of rattlesnakes?

Yes. Conditions of prolonged heat and drought are difficult to survive for any age of rattlesnake, with newborns being especially susceptible. In the summer of 2020, during a long period without rain and excessive heat, we observed that speckled rattlesnakes more often gave birth at aestivation dens rather than move to typical locations. This was mirrored in birthing events of Western Diamondback Rattlesnakes and others, giving birth in less-than-ideal situations. While these effects aren’t well documented, our observations and anecdotal experience with birthing in urban situations show, essentially: panic.

What do rattlesnakes do on hot ground or pavement when it’s this hot outside?

They die. This is why it is avoided at all costs, and it’s lethal to them when the fire department dumps them into a bush rather than relocate to a suitable area.

Are there any repellents that can be used to keep rattlesnakes from spending the summer in my cooler, wetter backyard?

Unfortunately there are no snake repellents on the market that will keep snakes of any species away, despite claims. The effective alternatives are a combination of habitat and resource reduction and, where applicable, snake fence installation.

Do rattlesnakes mate when it’s this hot?

Rattlesnakes can court and mate at any time of year, but typically the seasons for doing so are in the spring and fall, depending on species.

Is it ok to leave water our for rattlesnakes and other wildlife?

Yes it is! Just be sure that it is clean and does not become a disease vector. Also understand that doing so will indiscriminately invite wildlife to the area, and it’s not possible to pick and choose. Leaving water out for birds and bunnies is the same as doing so for rattlesnakes.

Are there specific scents or chemicals that can be applied to deter rattlesnakes? How about plants?

There are currently no products, operating either by scent or otherwise, that will effectively deter rattlesnakes and would be legally and ethically feasible.

The rumors about plants such as rosemary, lemongrass, mint, and other “snake-repellent” plants are just local mythology. Ironically, some of these, such as rosemary, provide deep ground cover that can actually attract rattlesnakes.

Does the application of lava rock, gravel or other small rocks deter rattlesnakes?

While these materials do not directly deter rattlesnakes, they may provide some protection in some areas simply by being hot ground cover. However, using these materials specifically for rattlesnake deterrent purposes would not be advisable. Remember that rattlesnakes live in very hot, rough environments. Using rocks, even sharp rocks like lava rock, would not have an effect.

How often do rattlesnakes need to drink?

If given an opportunity, they can drink every day. However, they are very efficient and many ways of preserving moisture through their behavior and physiology, and can go for several months without a drink if they must.

What can I do to help the rattlesnakes without causing unintended danger (to either them or me)?

This may seem like a non-answer, but simply having the attitude that rattlesnakes should be kept alive and are important wildlife is an important node contributing to changing culture. Perhaps the best thing someone can do, if they are aware of the potential risks associated and are able and willing to communicate as needed to visitors and others, is to simply leave the rattlesnakes in place.

At my own home, for example, we have discovered an aestivation den of Western Diamondback Rattlesnakes hiding out under the AC unit behind the house. It’s not in an area with immediate concern, but we know it’s there and make sure we behave appropriately. Rather than relocate these, we will allow them to stay there for the remainder of the aestivation period, then will likely repair the leaky AC drip that has caused the situation. We know there are several nearby and suitable aestivation sites in the immediate area, so loss of this one will not have negative consequences for these snakes.

Scam alert: Yes this is a real rattlesnake, no it wasn’t found where it says it was.

If you are a member of any local buy/sell groups, you’ve likely seen this post out there. If you do, do not share it – it’s part of a scam to create viral posts in these easy to get into and usually poorly moderated groups.

Is this rattlesnake fake?

Not at all. It’s a real snake; an Ornate Blacktailed Rattlesnake (Crotalus ornatus) from the mountains of Texas where they are found. This one was photographed several years ago within its natural home range by a rattlesnake educator named Tim Cole.

Quick correction of BS associated with this scam trend:

  • Rattlesnakes are not increasing their range – in fact most species are losing ground quickly.
  • This rattlesnake is not an albino – it is a normal coloration and appearance for the species.
  • “Scientists don’t know everything” and similar comments: because it is a mystery to some does not mean this snake is a mystery to those who study them. If you just learned about the existence of this species from this scam post, consider that herpetologists are more knowledgeable than you are on the topic.

If you see this post:

  1. Report it to Facebook as false information
  2. Post this article into the comments so that others can be informed and stop spreading it.

Rattlesnake in a Pot: The Latest Trending Misinformation

This photograph been circulating in recent weeks – a Western Diamondback Rattlesnake coiled in a potted plant. It has, as these things tend to do, taken on a life of its own since then and the waft of BS is all over social media.

Is this photograph real?

Yes it is – it’s really nothing out of the ordinary. This is a Western Diamondback Rattlesnake from somewhere in the eastern end of its range (more than likely Texas). It’s sitting in a potted plant, which is both cool and humid, which anyone living outdoors right now is into.

What isn’t real?

The misinformation surrounding where this has been posted is inaccurate. It’s currently circulating around gardening groups, community pages, and anywhere that trolls and needy personalities find useful to scare people for attention. Western Diamondback Rattlesnakes do not live anywhere near Oregon, Idaho, Ohio, northern California, Florida, or many of the places it’s been claimed to originate. It’s also not from Arizona, as we have seen several claim already.

What is really interesting about this, but not too surprising:

The number of people who post this with false information who claim that it is their own photograph, and first-hand experience. To anyone tasked with unraveling the waves of bad information and personality disorders associated with rattlesnake misinformation, this is a normal phenomenon. Many who spread misinformation like this do so without knowing that it’s already been shared thousands of times at this point, so claims like “this morning in my garden”, often posted from locations where this could not possibly have happened, are extra silly.

Should I worry about this and stop gardening?

Absolutely not. Realize this is viral for a reason: it’s interesting, unusual (to most), and meant to get you excited, scared, worried, or whatever else you may be feeling. If anything at all, if you live in an area where rattlesnakes do occur, just take it as a reminder that rattlesnakes could be found in your garden at some point, and take the necessary precautions.

Why do people prefer misinformation to reality?

Who knows. But with rattlesnakes in particular, it is very common.

Rattlesnake spring emergence – ultimate guide for homeowners

In the past few days, I’ve been to a multiple homes to catch rattlesnakes in garages. That’s normal and right on time. Which brings up the topic: when do rattlesnakes start moving again, and what should homeowners expect?

When will rattlesnakes come back? Our predictions, based on 11 years of relocation hotline activity:

Early February (you are here): Rattlesnakes will start to “stage”, or move closer to the entrance of, their winter dens. We will start to receive calls to remove small groups of rattlesnakes from garages, storage closets, sheds, and other out-of-the-way structures. Rattlesnake removal calls will frequently be multiple animals.

Late February: Rattlesnakes will start to appear out in the open near their selected dens. Garage removals will be more common. However, there will be an increase of calls to pool pumps, courtyards, and homes with rip rap and rock pile erosion control.

Early March: Snakes will start to make short movements from dens to hunt, drink, and engage in social behavior. They will be highly visible on the surface with peak activity occurring mid-morning before returning to the den or other nearby staging area. Mating activity is high, and multiple snake removal calls will be common.

Late March: Rattlesnake sightings will become common as they leave dens entirely. Peak activity will be between 3pm and 5pm.

April: Very high rattlesnake activity and sightings will be common. At this point they have entirely left the dens and sightings are more likely to be random encounters.

New! Rattlesnake Activity Forecast

We have a brand new Rattlesnake Activity Forecast tool! It’s based on real-time snake removal hotline activity. You can also check your zip code to see what kind of activity has happened in your area in the past.


Other good rattlesnake safety stuff to keep in mind:

  1. Don’t worry. This is totally normal, even February sightings (don’t listen to the local news about “coming out early” stories).
     
  2. If you’re a hiker or outdoorsy type, you’re still not likely to see a rattlesnake in February. Be more watchful and aware in March, however. 
     
  3. Now is the best time to get to any maintenance or prevention activities you have on your to-do list. Landscaping, debris removal, fixing the snake fence, having the dog trained … get it done before the snakes show up.
     
  4. Rattlesnakes often den in the garage. If you are using these last mild-weather days to get to “that” side of the garage, use extra caution.

Educating yourself is the best way to stay safe and feel better about the whole situation

As with most things, fear of rattlesnakes is mostly in our heads. Not the fear itself of course, that’s a real thing, but most of what we believe about rattlesnakes as a culture is simply false. Down to the idea that they are aggressive, or territorial (in the way that people use the word) and more, most of us just haven’t had an opportunity to learn factual information.

If you fear rattlesnakes, spend an afternoon going through these resources and watch what happens 🙂

Videos of early-spring rattlesnake captures and info:

The spring emergence of rattlesnakes is a big topic with homeowners and hikers – obviously we’ve discussed this in the past quite a lot! Here are some of those articles that can help make sense of it all.

When do rattlesnakes go away for the winter?

Temperatures are dropping, and so is snake activity. Every year, we are asked this question and field hundreds of comments wanting to know when the rattlesnake-phobic can once again breathe a little easier.

Even more common, starting in September, people are surprised that snakes are still active. We get comments like “this late?” and “I thought they were hibernating?!”. The answer is of course a little more complicated, but the answer is easy to find.

When do snakes go away in the winter?

According to hotline activity as an indicator of snake activity, snake activity drops dramatically around the second week of November. While snakes can still be found on the surface here and there, this is effectively the end of “snake season”.

This question can be best answered by looking at the average activity on our relocation hotline. Since this is driven purely by chance encounters by homeowners and businesses, it’s a good indicator of how many snakes the general population could expect to not see snakes out there.

But I heard that snakes are active all year?

Yes they are, but to a much lower extent. You may be told that there is no such thing as “snake season” because rattlesnakes can be found any time of year. While it is certainly true that in the right conditions a snake might make an appearance, it’s not necessarily useful for this discussion.

If a snake is found at your home in the winter, it has likely been there for awhile.

Here’s a better, more detailed article about When snakes “go to sleep” for the winter”:

When do snakes “go to sleep” for the winter?

And, similar information phrased differently:

Rattlesnake in a house! How does this even happen?

A rattlesnake in the backyard is one thing … but how about in the house, in the bedroom, and even under the bed? It happens, though, thankfully very rarely.

The thing is: rattlesnakes don’t want to be in your home. There are species of snakes that get in often, daily even, like Nightsakes and baby Longnosed snakes. Rattlesnakes, on the otherhand, for one reason or another just don’t make an effort to come inside. If I were to assume, based on how rattlesnakes handle stress and modify their behavior accordingly, the activity inside a home makes them less than ideal hiding spots.

This rattlesnake was found inside a home; a rare event.

How often does a rattlesnake get inside?

Fortunately, Rattlesnake Solutions has a very large collection of human-conflict data of this sort from over ten thousand individual encounters. It happens, but not very often.

Of all encounters we’ve documented, fewer than 100 were rattlesnakes inside the home. If you remove homes that were previously abandoned, missing entire walls, or in a condition where they should be condemned … you end up with fewer than 40. That puts the chances of a rattlesnake encounter in your home, based on snake removal records, at 0.4%. That puts it into a solid “don’t worry about it and go on with your day” category.

Most of the time, a call to catch a rattlesnake inside a home ends up with a Desert Nightsnake in our bucket. These little guys look quite a bit like a rattlesnake and are often mistaken for them.

Not a rattlesnake.

How does a rattlesnake get into the house?

Fortunately, rattlesnakes are easy to keep out of the house. They come in the same way we do – right through the front door. Most of the time, a rattlesnake inside a house, and in fact a good portion of the other types of snakes as well, come in through a door left open.

Who leaves the door open in Arizona? Everyone, it seems, on the right cool day. Especially our midwestern friends, where it seems an open backdoor on a breezy spring day is a normal thing, tend to leave that sliding door open a bit during prime rattlesnake activity time.

They also can get in through any other opening. Famously, the wife of a former Maricopa County Sheriff was bitten by a rattlesnake in her office. The reason? Workers had opened gaps into the home, which allowed the snake easy access.

On other relocation calls where we’ve captured rattlesnakes inside the home, the situation is often similar. A home with a wall partially removed during construction, a partially-completed vent removal allowing access, large gaps under garage doors or patio doors, etc. Simply, if there is access to inside the home, animals may find their way in.

What’s going on with this photo of the rattlesnake under a bed?

This photo was from an apartment complex in the North Phoenix, Cave Creek area. Mitch ran out to capture it. Upon arriving, he assumed it would be another nightsnake (which it often is) and had to run back out to the car to get his tongs and bucket after seeing this.

Not a nightsnake!

He was able to quickly and safely capture it. But how and why was it in there? And does the resident need to worry about more of them?

As we described earlier, it turns out that the resident left the home for less than 5 minutes, leaving the door slightly ajar. That’s all the time it takes for a wandering rattlesnake to find the cool, air conditioned “cave”, and slip inside.

This also does not mean there are others. Rattlesnakes, while being quite social in a variety of situations, are most often found at homes alone. They do not, as a popular myth goes, travel in pairs.

This also does not indicate that there are more rattlesnake encounters in the Cave Creek area … that is just true, regardless of this particular encounter.

How to keep rattlesnakes out of the house?

The best way to keep rattlesnakes out of your home is to keep doors closed and eliminate access, down to a 1/4″ space.

Sometimes that can be tricky, however. Something we have seen with homes in the valley is an issue with how cabinets are put together. This seems to be the reason behind a majority of nightsnake visits, and at least a few rattlesnakes.

If you look under the sink in your kitchen or bathroom, you’ll most likely see the pipes disappearing into the wall in an orderly, well-sealed way. Behind the cabinets, though, is a different story. The pipes coming into the home may be unsealed. That means if there are any gaps under the cabinet overhang (there most often are), there’s a direct highway from under the home to your bedroom bathroom. This may also be the cause for your scorpion and rodent issues.

The easy fix? Seal the gaps under the cabinet overhang. You could go through the trouble to pull out the whole cabinet, but without knowing for sure there’s a problem to begin with, that’s probably overkill. A Saturday afternoon with some expanding foam is all you likely need.

This small Western Diamondback Rattlesnake was in a kitchen under the cabinets

The other thing you should do is to take steps to reduce the overall number of rattlesnakes visiting your property. That is best done by a combination of property modification (landscaping, etc., here’s our step-by-step guide) and physical barriers, like properly sealed garage doors and rattlesnake fence installation.

So rest easy. While a rattlesnake inside the home is something that does happen from time to time, it’s nothing to be overly concerned with. No need to call the realtor or burn the house down; just keep the door closed and you’ll be just fine.

Past due: Baby rattlesnakes are finally joining us

Better late than never – rattlesnakes are giving birth, even without the rain. One of the services we offer are serial property inspections, to continuously monitor properties to evaluate possible rattlesnake activity and provide recommendations to landscapers, pest control, and property managers.

We have been inspecting this particular property for many years, and this is the most interesting thing found there to date.

On the previous inspection, Greyson noted a shed skin in an area at the edge of the property. Knowing a fresh shed during this hot and dry period could indicate an estivation den nearby, he focused on that spot during his visit yesterday, and, whoa.

This mother rattlesnake gave birth to babies after being captured at a home in Phoenix.

Here is what was found: a late-season estivation den with a mixed bag of Western Diamondback Rattlesnakes, with one having given birth in the recent past, and another in a deep blue phase (preparing to shed skin)

While this is not entirely unusual, what is different about this year is that we are seeing that rattlesnakes are having their babies later than usual, and they are doing so in their estivation dens instead of moving to their usually-preferred birthing spots.

This is likely a response to our exceptionally hot (the hottest on record) summer and near-complete lack of rain. This is similar to a recent visit to a home by Dave in Tucson (I’ll be posting this shortly as well) where he captured a total of 14 rattlesnakes.

Are rattlesnakes giving birth later this year than normal?

According to our observations and activity on the relocation hotline: yes, it appears that rattlesnakes are having babies later this year than usual. In a normal year, we start to receive our first calls to capture groups of mother Western Diamondback Rattlesnakes with their newborn babies in early July, usually hitting its peak around the first week of August, then trickling in here or there until around the first week of September. This year, it took much longer for this to be normal, only now (mid-August) has it become routine.

Rattlesnakes give live birth and hang out with the babies for a period of time afterward.

Likewise, rattlesnakes seen in informal surveys and in our study of rattlesnakes in the Phoenix Mountain Preserve have shown that Western Diamondback Rattlesnake and Tiger Rattlesnakes that would have likely given birth by now are still languishing in a gravid (pregnant) state at estivation dens.

While this is in no way a full representation of what’s happening out there, but does represent 10 years of data collection and informal survey observations. It should also be noted that while this is the case in the Phoenix and Tucson areas, it is unlikely to represent behavior in other regions.

Why are baby rattlesnakes being born later this year than usual?

The most notable difference of this year from previous years is the combination of extreme, prolonged heat and a nearly-complete lack of meaningful rain. It has been documented that the birth time of Western Diamondback Rattlesnakes coincide with the onset of the monsoon rain (G. Schuett et all 2013).

This year makes that a little bit tougher than normal. If monsoon rain triggers pregnant rattlesnakes to give birth, what happens when there is no rain at all?

They have to give birth eventually … so what we are seeing is this: The mother rattlesnakes are staying at estivation sites (spots selected to hide away during the hottest summer months) far longer than they normally would. Rather than moving to a birthing site as they normally would, they are having their babies right in place.

This likely isn’t good for the babies, ultimately and unfortunately. They lose moisture more than twice as quickly as adults (J. Agugliaro, H. Reinert 2005). Unless we get some rain soon, that could be big trouble for this year’s babies. We’re hoping for the best, but looking at the forecast … hoping is all there is to do.

How homeowners can keep baby rattlesnakes out of the yard

Keeping the smallest rattlesnakes out of your area is a bit different than the larger ones.

First, the space they need to get in is much smaller … anything more than about a third of an inch can allow access. Second, they make frequent movements and may not necessarily know where they’re going. Unlike adults, who’ve had a lifetime to map out a homerange, babies may show up any place, any time. For that reason, physical barriers are the best bet. Rather than go too far into detail here, I’ll refer you to our guide to keep baby rattlesnakes out of the yard.

References

Schuett, G.W., Repp, R.A., Hoss, S.K. and Herrmann, H.‐W. (2013), Parturition in a Desert Rattlesnake. Biol J Linn Soc Lond, 110: 866-877. doi:10.1111/bij.12166

Agugliaro J, Reinert HK. Comparative skin permeability of neonatal and adult timber rattlesnakes (Crotalus horridus). Comp Biochem Physiol A Mol Integr Physiol. 2005;141(1):70-75. doi:10.1016/j.cbpb.2005.04.002

What can “snow birds” do to keep rattlesnakes away?

Arizona’s perfect weather in the shoulder seasons makes it an ideal place to spend the winter for seasonal residents. Affectionally referred to locally as “snow birds”, each year, they come and go. With their return to roost in the fall come the flurry of rattlesnake removal calls.

What do rattlesnakes do when we’re away?

Rattlesnakes make use of unoccupied homes.

One of the apparently largest factors in rattlesnake activity (or lack of it) is simply your presence. Just our activity on the property can alter their behavior so they take greater care to avoid meeting us.1 So when you leave, it’s to be expected that wildlife will quickly move to reclaim the space. Even a few months can make quite a difference. We have learned this from 10 years of rattlesnake removals and working with property managers – a unoccupied home can greatly affect the chances of future rattlesnake encounters.

So what can we do to reduce our chances of having rattlesnakes move in?

What can you do to keep rattlesnakes and other wildlife from squatting on the property while you’re away? Aside from the easy stuff (covered here in our 5 Things you can do right now to see fewer rattlesnakes guide), there are a number of things you can do both before you leave, while you’re away, and prior to your return.

Before you leave:

Rattlesnake Fence Install
Get preventative barriers in place before you go.
  1. Physical barriers are the best bet. Get rattlesnake fencing installed. If you already have it, make sure that it’s in top form and there are no holes, gaps, or damage that needs attention.
  2. Get rid of any debris – piles of construction stuff, roof tiles, those bricks by the side of the house, or deflated pool toys, etc.
  3. Ditch the lantana! Get to any last-minute landscaping choices before you leave. The fewer places snakes can hide, the better.
  4. Fix it! Repair any holes or gaps in the building, foundation, flashing, grill islands, or anywhere else that could become a summer home for snakes.
  5. Avoid making a cave. Make sure the garage is sealed up tight and in great condition.

While you’re away:

Regular activity in an area helps keep snakes away.
  1. Keep up on maintenance. This might cost some money, but making sure the services to maintain the yard are still in place can help keep rattlesnake activity away. A well-maintained yard that’s occasionally visited by people is less attractive than yards that are not.
  2. Get it checked out. Have someone knowledgeable about wildlife come do an inspection mid-way through your absence to identify any potentially problematic areas before they fully develop. You can also just ask a neighbor or a property manager to walk the property.

Before you return:

A well-maintained property is less likely to have rattlesnakes in int.
  1. Have the yard inspected. A few days before you come back, it may be a good idea to have a property inspection performed to make sure that any snakes that may have moved in while you were away can be found and removed.
  2. Do a once-over maintenance. Even though you may have keep the landscapers and pool guys coming the entire time, it’s a good idea to do a final touch-up just before you arrive. Rather than waiting until you get there, if you can get this done in advance, that will help eliminate the chances of displaced rattlesnake encounters.
  3. Read up on local snakes. Many of our snow bird residents actually come from those far-off summer destinations, so knowledge of the native wildlife is still a work in progress. During that long drive (passengers!) or wait at the airport for your return, brush up on knowledge of what may live in your yard and how to identify it.

Once you return:

Look for any visitors who may have moved in over the summer.
  1. Walk the property. While everyone is unloading the car, get right to it: walk the entire property and do a check to see if anyone else is there. If you do find a snake, call to have it relocated ASAP.
  2. Be on guard. For a week or so after you come home, be more cautious than normal and make be aware that the new activity in the area may change the behavior of wildlife, including rattlesnakes. That also goes for the return of your neighbors.
  3. Check the fence! Make sure that your rattlesnake fence is still tight and without damage. Rodents and other animals can sometimes dig or create problems even while you’re gone, so do the same inspection you did before you left to make sure it’s still good to go.
  4. Get to the big maintenance. For which items to focus on and lay out your time, refer to our How To Keep Snakes Away From Your Home – The Ultimate Guide
  5. Jump in the pool! This has nothing to do with snakes, but you’ve probably been thinking about it for a while so go for it.

Welcome back! Keep the education going.

The more you know, the safer your yard will be. Not only will you be better equipped to make your yard less attractive to snakes, but your behavior if you do see one will be better. Here’s a rather long presentation full of information that would be a good once-over when you get back to help you feel better about the whole situation.


  1. Meghan Beale, Stephane Poulin, Craig Ivanyi, Gabriel Blouin-Demers 2016.  Anthropomorphic Disturbance Affects Movement and Increases Concealment in Western Diamondback Rattlesnakes (Crotalus atrox) Journal of Herpetology, Vol. 50, No. 2, 211-221, 2016.

Arizona pool owners: avoid making a rattlesnake guest house

Over the past decade and many thousands of rattlesnakes captured in the backyards of Arizona homes, a few trends have emerged. Most notable: there are certain areas of all yards that seem to attract rattlesnakes more often than others.

Perhaps the biggest offender on this list of rattlesnake-attracting features are pool filter systems. Throughout the year, especially during the spring and late fall when rattlesnake behavior is driven by access to their dens, pool equipment areas seem to house rattlesnakes more than any other yard feature.

Why does pool equipment seem to attract rattlesnakes?

Every home with a pool has a corner of the property where the filter, pump, heater, and other pool mechanisms are hidden away. These items themselves aren’t useful to rattlesnakes – in fact, I would suspect that the constant vibration and smells could be disliked by them. However, there are some pretty great things here if you happen to be a rattlesnake:

  1. Privacy – They are often tucked away, obscured by a wall, and seldom visited compared to other areas of the yard.
  2. Comfortable – They often become the default storage area for materials for unused roof tiles, pavers, and deflated pool toys.
  3. Opportunity – The vibration and moisture from the equipment can help turn any rodent burrow into a deep cave system.
  4. Fast food – rodents easily make homes in the soft dirt and create burrows under concrete base slabs.

More or less, these issues stem from the fact that most designers make an effort to hide the mess of pipes and noisy equipment away from the rest of the yard. As a result, common problems that would otherwise be addressed immediately. Rodent activity, discarded pool toys, materials waiting for bulk-pickup day, and others are often put here and forgotten, inadvertently creating the perfect situation for rattlesnakes to find a home.

The base of this concrete slab had an old rodent burrow under it – widened by vibration and erosion from the equipment, it became a perfect hideaway for a rattlesnake.

How do I keep rattlesnakes out of my pool equipment?

Fortunately, this is relatively simple. All you need to do is treat this part of your property the same as you do the rest of it.

If you follow our other articles and social media content, you are already quite familiar with how to keep rattlesnakes out of a yard (if you’re new, our Ultimate Guide to Keeping Snakes Out of Your Yard is a great place to start).

If you are diligent about addressing rodent issues that appear in the visible parts of your property, extend that effort to the hidden pool pump stuff as well. If that inflatable shark you haven’t floated on since the first 5 minutes it came out of the box is just deteriorating behind the filter, throw it away. Likewise, find a new home for the old roofing tiles, the broken pool net, etc. Keep this area as clean and well-maintained as you would any other part of the property.

This yard was absolutely beautiful and perfectly-maintained, but a years-old rodent burrow went unnoticed in the pool filter area, and this Western Diamondback Rattlesnake found it to be a perfect winter home.

Above all, make sure that the concrete (or other material) base slabs have no tunnels or erosion under them. These tunnels seem to be exceptional homes for several behavioral phases of rattlesnakes throughout the year, and one of the top situations we remove snakes from each year.

So, the next time you’re in the backyard doing your normal maintenance, give the pool guy a break from a possible rattlesnake encounter and take care of those hidden-away areas, too.

The first rattlesnake sightings of the year! Here’s why you shouldn’t worry.

It is completely normal to occasionally see rattlesnakes in the winter. The first rattlesnake sightings of the year have started to pop up around Arizona, along with the subsequent misinformation. To get a jump on things, let’s clear a few things up. Copy and paste this as a response to all the “OMG it’s too early!” comments you see out there 😉

This Western Diamondback Rattlesnake was found sitting outside its winter den on a cold, rainy day (45˚F), hoping for a chance to drink. This is normal behavior.
  1. Rattlesnakes are not out early; some reported sightings are completely normal. You do not need to worry or stop hiking, etc.
  2. It is not “too cold”. Any day with the right conditions can have rattlesnakes coming to the surface of their chosen den. This can happen any day of the year when things are right.
  3. Rattlesnakes do brumate (hibernate) and do have distinctly different phases of behavior as seasons progress. However, part of this behavior includes the need to come to the surface in certain conditions. In particular, moisture and the chance to drink means you can potentially see a rattlesnake on the surface even in the cold months. This doesn’t mean “they don’t hibernate”, but that this behavior is more complicated than most people expect.
  4. Yes, you can see rattlesnakes on rare occasions, under very specific circumstances, in very specific places. “They are out” as they are all year, but this does not mean they are ACTIVE or that you need to worry if you’ve heard of someone seeing one. A number of these snakes are due to human causes, like construction, removing an old shed, or getting into the long-overdue garage cleanup. If a snake is uncovered by our behavior, that is not an “active” snake, but a discovered and displaced one.
  5. No, rattlesnakes have not started to move around and begin a major activity period similar to the Spring emergence, which will likely start right on schedule around mid-March. They’ll likely stay right at the place they’re at (or within a few dozen feet) until conditions signal that it’s time to go.
  6. Rattlesnakes are not “more aggressive” as they emerge from winter dens. If this is not a complete myth, it is likely one created by confirmation bias and a possibly delayed defensive reaction (rattle) as hunters and hikers approach a denning snake.
  7. Rattlesnakes don’t form massive winter dens in the low desert. On TV and in internet posts, you may see photographs of hundreds of rattlesnakes piling out of a hole in the ground. In the hot desert areas of Arizona, this is not what they do. A rattlesnake den in the Phoenix or Tucson areas will usually have between 1 and 5 individuals, with some special places having a larger number.
  8. If you do see a rattlesnake at your house, it’s almost certainly been there since October or so. This would be a good time to contact a professional to investigate.
  9. Right now is the best time to get started on any pre-season landscaping, yard cleanup, or any other habitat-reduction methods of rattlesnake prevention. Don’t wait until it gets warmer.
  10. The superbowl is soon! If you’re grilling, do a quick inspection under the grill island before your guests arrive. Stand-alone grill islands that are popular in Arizona are a popular site for denning rattlesnakes.

If you hear anything else and want some clarification, post it in the comments!

Rattlesnake at its den in central Arizona. It may come to the surface to get a drink, but it’s not going anywhere until its ready.

More articles about rattlesnake winter activity: