The Cottonwood stage beetle is quite common in Arizona, but they are not as dangerous as they are perceived to be. Learn more in the article below.
Stag beetles are the often highly misunderstood members of the Lucanidae family. There are between 800 to 1,250 species in this family
These beetles are often considered extremely dangerous due to their appearance, simply because they have huge protruding mandibles.
The fact is, most of them don’t have strong enough mandibles to bite. The cottonwood stag beetle is one such insect found in Arizona, US.
In this article, we will determine if the cottonwood stag beetles are as dangerous as they look.
What Are They?
Cottonwood stag beetle (Lucanus mazama) are found in regions with loose soil and high temperatures.
As the name suggests, these beetles live in Riparian areas with an abundance of old cottonwood trees.
These insects have glossy back-colored bodies and can show an average growth of 1.02-1.14 inches in length.
Like other stag beetle species, they also have strong and long mandibles. They use these primarily to eat tree sap. They also have a hard outer shell and a pair of wings.
What Do They Eat?
As larvae, cottonwood stag beetles consume a lot of dead and rotten wood. They use their jaws to tunnel through rotten wood to find white rot to consume.
They like to infest deadwood of willow, oak, lime, and ash trees. Since they only consume rotten wood, small plants and shrubs are usually safe from these creatures.
The adult beetles usually don’t eat. They rely on the fat reserves that they gain during the larval stage.
Where Are They Found?
In the US, you can find these insects in parts of Arizona. Also, you can spot them in some parts of Southern Asia and Australia.
Proper stag beetle habitats are the areas that receive less rainfall and high temperatures.
These beetles also consume woodchips in playgrounds, so there is a high possibility of spotting them near such spots.
Are They Harmful?
As mentioned above, stag beetles have large mandibles that look similar to the antlers of a stag. The males usually have larger mandibles than the female beetles.
But the reality is that these insects are not aggressive, and they rarely ever attack humans. But that does not mean that you should throw caution to the wind when around them.
Both male and female cottonwood stag beetles can deliver intensely painful bites, which can cause redness, swelling, pain, and rashes.
While the pain usually subsides within an hour or so, it is best not to mishandle them.
Are They Poisonous?
The cottonwood stag beetle is not poisonous at all. They may look scary, but they do not usually attack humans.
But still, they pose a threat of delivering painful bites; therefore, you must not be reckless around them.
Are They Beneficial?
It can be beneficial to have these insects around your garden, especially during the mating season. Their larvae actively consume dead and decaying wood and vegetation.
Thus, they can be an excellent way to clean your garden of wood carcasses. Adding to that, they do not cause any harm to your decorative small plants and shrubs.
Frequently Asked Questions
What do Cottonwood stag beetles eat?
Cottonwood stag beetle larvae usually consume the dead and rotten wood of cottonwood trees. They like to infest decaying ash, oak, willow, and chestnut trees.
The adults, on the other hand, do not consume anything; they rely on the fat reserves that they gain during the larval stage to stay alive.
Is a stag beetle harmful?
Stag beetles may look tough and dangerous, but they are non-aggressive insects. They rarely attack humans.
However, you should never be reckless around them as they have strong mandibles and deliver painful bites.
They have strong chewing muscles that can help them break past the human skin.
What happens if you get bit by a stag beetle?
If a stag beetle bites you, there is a high chance of experiencing intense pain.
Since they have mandibles that are strong enough to break past the skin, you might notice bleeding and redness in the area.
However, thankfully, these bites are poisonous. They won’t cause any fatal injuries or illness.
What should I do if I find a stag beetle?
If you find a stag beetle, do not approach or touch it recklessly.
Since they have solid mandibles and strong chewing muscles, they can deliver intense painful bites.
If you want to touch them, it is better to use gloves to stay safe.
Cottonwood stag beetles and other giant stag beetles can look intimidating but these creatures are mostly harmless.
But since they have large jaws, they can deliver painful bites. You must be careful around these beetles.
At the same time, you should know that they are not poisonous. Thank you for reading the article.
Cottonwood beetles are quite common in Arizona, and we have received many emails over the years from that region asking us to identify the particular species.
Here are some of the pictures and emails from our readers.
Letter 1 – Cottonwood Stag Beetle
what is the name of this beetle Location: Orem, Ut July 1, 2011 10:02 pm We found the following beetle on July 1st, in Orem UT, at a public park among the wood chips. It was 7 p.m. at night and there were several of these beetles walking around the wood chips. Signature: Dante Hi Dante, This is a male Stag Beetle in the genus Lucanus, but your location in Utah is a bit far west for the species we usually receive. We did some research on BugGuide, and we believe this is a Cottonwood Stag Beetle, Lucanus mazama, and if we are correct, this represents a new species for our website. Daniel, Wow thanks for getting back so soon.My five year old son is an avid bug lover and he thought it was great that he found these beetles. What’s funny is he insisted that they were a type of stag beetle, but we couldn’t find them on the web. It’s interesting you say they’re a bit far west because we saw between 20-30 in the playground. He’d like to know what they eat. Thank you for your info it’s been helpful. Dante Hi again Dante, We should probably clarify what we meant by our “west” comment. Most of the North American Stag Beetle submissions we receive are from two species, the Reddish Brown Stag Beetle, Lucanus capreolus, and the Giant Stag Beetle, Lucanus elephus. The furthest west we know of for those two species is Texas. Your beetle is a different species, the Cottonwood Stag Beetle, Lucanus mazama, and BugGuide has only received submissions from Arizona and we have never received a submission of that species prior to your letter. You can try feeding your Stag Beetles overly ripe bananas or other very ripe fruit. Stag Beetles are believed to feed on tree sap, but there is not much available information that we are aware of regarding the feeding habits of Stag Beetles in the wild. We are fascinated by the wood chip connection. We just located these reports from Europe (they have their own species there), that Stag Beetles are being found in places landscaped with wood chips. This is the best article we have read online in a very long time.
Letter 2 – Cottonwood Stag Beetle
Subject: Cottonwood Stag Beetles Location: Lehi, Utah June 29, 2015 12:36 pm Hello! I came across your site while trying to identify (what I now know is) a Cottonwood Stag Beetle in Utah. I added my own comment to the topic on your site and saw you mention you’d be happy to receive photos by submitting them through this link, so here I am! I don’t know what you’d do with them, but I’m happy to share… Signature: Jenny Jones Dear Jenny, We are a bit behind in posting identification requests, but we are thrilled to post your image of a Cottonwood Stag Beetle as we have received several recent comments, but no new images.
Letter 3 – Probably Cottonwood Stag Beetle Grub
Subject: Cottonwood stag beetle Location: Orem ut January 1, 2017 5:37 pm We have what we believe is a cottonwood stag beetle larvae. He is over 2 inches long and has large pinchers. We found him buried in the wood chips at the playground where we have seen the really big cottonwood stag beetles and we are assuming for its size and location that is what we have. My kids really want to “raise” it. We have kept it in a jar with wood chips for about 3 months. We occasionally add a little water. I can’t find anything about it’s lifecycle. What else can we do to ensure a successful metamorphosis in the spring/summer. We check every few days for movement through the glass, so far so good. Signature: Jr entomologists Dear Jr entomologists, You are our first posting of the New Year after returning back to the office today. We agree that this is most likely a Cottonwood Stag Beetle Grub since you have found adults in the vicinity. Your individual looks like the Stag Beetle Grub pictured on BugGuide.
Letter 4 – Cottonwood Stag Beetles
Subject: Cottonwood Stag Beetle Geographic location of the bug: New Castle, Colorado Date: 06/26/2018 Time: 12:25 AM EDT Your letter to the bugman: I was picking up some trash in my yard when i noticed a pretty big black beetle eating what looked like a smaller beetle without its head. I took it inside to show my family and when I went to go let it back outside there was another one right where i found the other one! How you want your letter signed: KD Dear KD, Thanks so much for sending in your images of male Cottonwood Stag Beetles, Lucanus mazama, though we believe the predatory behavior you believe you witnessed was actually something else. The Generic Guide to New World Scarab Beetles has a nice comparison to help differentiate the sexes of the Cottonwood Stag Beetle.
Letter 5 – Cottonwood Stag Beetle
Subject: Cottonwood Stag Beetle Geographic location of the bug: South-Central Utah Date: 08/04/2018 Time: 01:53 PM EDT Your letter to the bugman: I noticed in one of your posts you mentioned being surprised that these beetles range as far west as Utah. This one was found (alive) near Capitol Reef National Park. I’ve lived here for nearly 20 years and this is the first one I saw here. Perhaps range is extending due to climate change. Anyway, thought I’d provide another specimen for your guide. How you want your letter signed: Guy Tal Dear Guy, Thanks so much for providing this awesome image of a Cottonwood Stag Beetle.
34 thoughts on “Cottonwood Stag Beetle: Is It Dangerous?”
We just found a large group of these in the wood chips at Bear Park in Sandy, UT. Another connection with the wood chips such as you mention above.
This is quite interesting. It seems the use of natural wood chips for landscaping and mulch might be providing much needed habitat for Stag Beetles.
We live in Draper Utah and just found one on the side of our house on our porch at night. I have never seen one of these…except in an Indiana Jones Movie! Do they bite with those pinchers? We caught it so we could look at it and then let it go.
I also found one of these stag beetles in my backyard this evening, about 8:00 pm, here in Salt Lake City, UT. The nearest tree about 10 feet away was a Hawthorne. The Hawthorne appears to have some 1cm or less bore holes in it, in a somewhat dead part of the tree (it’s an old tree); not sure if those were there before this season (but I think so).
I don’t really know if the two are connected, but I can’t imagine this thing is good for the yard. The other nearest trees are an old walnut tree and old peach tree in adjacent yards. It’s now in a glass jar, doing a push up every minute or so.
Coincidentally, like in the top photo the one I caught also only has 5 of 6 legs (back right leg missing).
Bugges Out in SLC
Stag Beetles do not compromise living trees. The grubs feed on rotting wood. Rotting wood needs to be broken down so that the nutrients can be returned to the soil as humus. Without insects like Stag Beetle Larva to help in the decomposition, soil quality will deteriorate. One can make that defense for Stag Beetles being good for the yard.
We have a good population at our Fillmore, Utah home..
We have a small farm out by the Tabby Turn in Fruitland, UT. Have not seen any adults yet but over the 24th holiday, we found numerous (like 100+) larvae in various stages of growth all through our garden. Ranged from 1/4″ to 1″ in length. This is the first time we plowed in 3 years. I was wondering if the beetle larvae stay deep in the ground. We plowed up about 2 feet deep (and I was under the impression our area only grew kids and rocks :)). Also we have had quite a bit of rain lately, would that promote their growth ? besides our watering? Now that I am finding out a bit more about them, I have a few concerns. Are they into potatoes? that is where we noticed them first. Will the larvae crawl up a plant to get to the fruit or does it, the fruit, need to be on the ground ? My husband will let them be as long as they leave our food source alone. Are they similar to an earthworm in the benefit department ? Any help would be greatly appreciated.
In our opinion, the larvae you found are more likely some species of Scarab Beetle. June Beetle grubs are quite common in garden soil.
I just found a larger then normal beetle on my porch and started searching the net. I found this page and am blown away by what I and other people have encountered. I live on a small farm with tons of trees in South Jordan, UT. I touched the stag with a stick to see if it was aggressive, it just stayed put. He seamed quit strong and hardly moved. I let him be. I’m sure he and others live in all the downed trees on the property. Fun new information I’ve just found.
All of our reports of Cottonwood Stag Beetles have been from Utah, however BugGuide reports them from neighboring states Arizona, New Mexico and Colorado as well. See: http://bugguide.net/node/view/93340/data
We just saw hundreds of these beetles all along the Jordan River parkway in Taylorsville, Utah. I was trying to identify them because I had never seen one. All of them were in the wood chips covering the playgrounds, and the kids were playing with and ‘petting’ them.
I took my three young kids to the park here in Spanish fork, Utah. We came across 12-15 of these in the wood chips. The more we dug, the more we found. The original post by the woman who found them is similar to mine. My 5 year old is fascinated with them. Thanks for all the other people who left posts. These beetles are fascinating to me and my kids. I have photos if needed:)
We would love the photos. Please submit using our Ask What’s That Bug? link and please use Cottonwood Stag Beetles as the subject line.
I just wanted to add in my bug sighting too! We’re in Lehi, Utah and came across this beetle yesterday evening at the playground in the wood chips, just as everyone is describing. I’ve never seen such a beetle and thought it could be a different type of “stink bug” until coming across this site. (Thanks!) The pincers sure are scary looking! Do they bite? I was concerned about it being on a playground…who knows how many more could be hiding. Eek.
It is possible a pinch will occur if the Cottonwood Stag Beetle is carelessly handled.
I live in Anchorage, Alaska and we do not have many bugs. I killed one of these marching acroos the dining room floor last week. We do have a few Cottonwood trees in our neighborhood.
Playing today in a park (ground covered in wood chips. Surprise, surprise) in Midvale, and there were hundreds of these all over the playground. I’ve never seen one. Brought me here. Sadly, most of them were dead, some barely alive and a few healthy robust guys. I’m now wondering if this park has been sprayed. 🙁
Found one of these in a park in Holladay, Utah today. My 1 year old grabbed it and he sure got a pinch. I couldn’t get it out of his hand because the pinchers were in his finger. He cried for about 30 seconds and was fine after that. Hasn’t complained since then. Are their bites harmful?
Other than a pinch, and the possibility of drawing blood in a person with tender skin, there is no threat from the Cottonwood Stag Beetle.
I just had one land on me a night ago. I live in Abiquiu NM., right by the Chama river and we do have a lot of cottonwood and other trees. Also, several piles of wood chips.
I certainly hope you’re not going to “let it be free” if you and your children succeed? After all, it’s one of the most damaging species to these trees out there, and, another one we can thank, “Free Trade” for!
Wow. You are really funny spreading fake news that way. Of the Cottonwood Stag Beetle states BugGuide: “Range sw US (AZ-NM-CO-UT),” which we interpret to mean that it is a native species, though that range does include land that once belonged to Mexico before the Mexican American War. According to the History Channel site: “When the dust cleared, Mexico had lost about one-third of its territory, including nearly all of present-day California, Utah, Nevada, Arizona and New Mexico.” That could mean the Cottonwood Stag Beetles are actually a Mexican species. Alas, insects have no respect for international borders.
We are in Colorado, western slope. My husband took me outside this evening to see a different type of beetle ( he knows I like bugs ;). ) so we looked the beetle up and it is a male cottonwood stag beetle. He’s a very impressive fellow ! I’ve never seen before. This was a treat! Will take some photos then let him go. Thank you.
I live in Coloma Michigan and just saw my first Beetle that resembles the one above. Their looks sure are intimidating but then again most beetles are to me. I got him in a scoop and put him on the other side of the road to live. 😉
Do these fly? I found a similar one but it flies any ideas what it could be?
We believe Cottonwood Stag Beetles are capable of flight. Though it regards a different species of Stag Beetle, the Royal Parks site states: “Believe it or not Stag Beetles can fly. Males will fly out to look for a mate at dusk on humid, thundery evenings between May and August.”
Just found one in my home office. A rather large fellow. Body is about an inch long. I Live in Santa Fe NM. My first seeing this kind of bug. We’ve been doing construction in our rural setting. I suppose he tagged along inside on one of the dogs fur. As long as he isn’t going to hurt me or my pups I guess I’ll let him go tomorrow. He’s mine for tonight! Fascinating.
I woke up yesterday to find 16 of large beetles on the patio. Some had crawled into a pot but now cannot get out. I seem to notice them after a heavy rain which we had several days before. I live in Prescott Valley AZ, When they die they go belly up. Any particular reason for this?
I’m in Provo and I found one of these. It seems to be close to 3cm long, though. Does that sizing sound right?
size sounds correct
We just saw a bunch of these in the wood chips at dusk at a park in Lehi, UT. My boys are loving them.
I live in Santa Fe and am finding these beetles in our back yard, which is mostly gravel. Or I should say, our dog is finding them in the evening.
We are from Santa Fe, NM and we just encountered a huge amount of these stag beetles at our neighborhood playground. All living in wood chips!
Found a feisty 2 inch one in Mueller Park by Bountiful, Utah. I took a picture but can’t see a way to attach.