Dermestid Beetles

I’m not going to go into a detailed explanation of what they are, the history of their use, and the many studies that have been done on them. J.A. Long did this already in her book on the subject. Instead, I’m just going to give a quick run down on their basic care, caging, and use for processing bones.

(You can buy Dermestid Beetles here.)

The Enclosure

You can keep Dermestid beetles in a number of ways, from screen lid aquariums, to Rubbermaid plastic tubs with vent holes. The most common way is to convert a chest freezer, which you can read about here in my tutorial on the subject.

But the basics are having an escape proof enclosure (Dermestid Beetles cannot climb smooth sided enclosures) that stays around 78-80 degrees fahrenheit (anything over 80 and the beetles can begin flying), has at least a few inches of bedding for burrowing (Anything from aspen, cotton, cypress mulch, etc…), and providing cotton or foam pieces for burrowing and pupating. You can get creative with this. There is really no limit to how many ways you can keep them. I prefer my double door commercial cooler Dermestarium, which you can read about here.

Ventilation is a nice feature to prevent odor, but if you keep your beetles in a room or building where this isn’t an issue, then a simple screen lid will suffice.


Obviously they will usually just eat the specimens you are processing, but sometimes you may have nothing to offer them. In this situation, almost any form of meat will suffice. Even hotdogs. If you’re lucky you can score almost expired cheap brand meats from a local grocery store and just freeze it for future use.

A free alternative is to use the meat you remove from your specimens before drying. Just bag it up and freeze it, then dish it out as needed.

Preparing Your Specimen

The first step when you are starting with a whole raw animal is to prepare it for the beetles. To do this, in the simplest terms, you just take it apart. Remove the skin, eyes, organs, and then remove all the meat you can. Cut off the major muscles, and trim it close to the bone. This allows the animal to dry quicker, and the beetles to eat it quicker as well as before it rots if it isn’t dried well, which it probably won’t be dried well if you left excess meat on the bones.

A good dissection kit will come with more tools than you’ll even need, but they are cheap, and it is nice to have extra things around for unpredictable situations. I also recommend a nice Mayo Tray for working on and keeping fluids contained.

Drying Specimens

So you’ve processed your specimen and are ready for the next step? Well there is one very important part of beetling animals, and that is properly drying the specimen. Now I use my double door commercial cooler Dermestarium to dry mine, but there are other ways to do it. What you want is a specimen as dry as real beef jerky. Not the compressed bullshit jerky, the real deal.

This has a few benefits. One is that if you have a small colony it won’t matter how long they take to finish the specimen, it won’t start rotting. The second is that the ligaments become so dry that the beetles don’t like them and will avoid them until all of the meat is gone. This leaves the skeleton fully intact through the whole process. Then timing becomes important. When the meat is gone but the ligaments are still in place, pull the specimen.

One commonly used method is a Rubbermaid with a computer fan inside of it and vent holes covered by fine mesh screen to keep flies and gnats out, who will gladly lay eggs in your specimen which obviously turns it into goo crawling with maggots. Most people keep it outside. Leave it until the specimen is totally dried and very stiff. So stiff you can actually tap it on a hard surface. Mummified, essentially. Once it is at that point, give it to your beetles.

Beetling the Specimen

It’s time to offer the beetles your specimen, but are you just going to throw it in the colony and hope for the best? Of course not. One thing I see lots and lots of people do, and have myself done in the beginning, is just place an animal in the colony and then later realize those little kleptomaniac bastards stole some bones. If you’re lucky, you’ll find them in the bedding, but usually they seemingly vanish into thin air. There are two things that helps with this issue. One is drying the specimens first, and the second is mesh baskets.

You can buy various sizes of my favorite mesh baskets here.

So your specimen is fully dried and you gave it to your beetles. But timing is an issue now. Most of us work and have a life so we tend to not just sit by the Dermestarium waiting for the perfect moment. So it’s not uncommon, even with a properly dried specimen, to have a toe or two fall off due to the beetles chomping on ligaments. This is no biggy, as you can just glue it on later, but what if those little assholes take that toe and hide it? Well the answer is simple, just place the specimen in a metal mesh basket. Here are the ones I use. I keep every single size and multiples of the 6×12’s.


I often even dry the specimen in the basket in the top shelf of my Dermestarium, and then just place it in the colony when it’s ready. If a few small bones fall off, they are kept in the basket. Problem solved.

The beauty of these specific baskets is that the beetles can climb them, and crawl through the mesh holes, but just barely. They also have a metal rim around the bottom, so say a very tiny bone does fall through the basket, it will be laying under it when you lift it up. But most can’t make it through in my experience.

My double door cooler Dermestarium (View the build tutorial here) has a shelf for drying, and a shelf for placing beetled specimens and giving stuck and hiding beetles time to drop off. I take the basket from the top shelf, place it inside the colony, then when it’s time I pick it up, and put it on the bottom shelf. Within a couple of days all of the left over beetles have crawled out and dropped back into the colony.

Once all beetles are off of your specimen you are ready to degrease the bones. Check out my tutorial on Degreasing Small & Fragile Animals.