Preserving a dead bat requires careful handling for safety, a check on legal restrictions, and a preservation method matched to how you want to display or store the specimen. Bats can carry rabies and other pathogens even after death, so protective equipment is essential from the moment you first touch the animal.
Handle the Bat Safely Before Anything Else
Never touch a dead bat with bare hands. Wear thick gloves (leather or doubled nitrile) and use a shovel or tongs to move it. The rabies virus can remain in tissue and saliva for a period after death, and any scratch or mucous membrane contact poses a risk. If you’ve already handled the bat without gloves, or if anyone was bitten or scratched, contact your local health department immediately for guidance on post-exposure treatment.
Place the bat in a heavy plastic bag and store it in a cold location, away from people and pets, until you’re ready to begin preservation. Clean the surface where you found it with a solution of one part bleach to ten parts water. If there’s any chance the bat was behaving oddly before it died (flying during daytime, unable to fly, approaching people), your local health department may want to test it for rabies before you proceed. A rabies test destroys the brain, so it’s worth resolving that question first.
Check Whether Your Bat Species Is Protected
Several bat species in the United States are listed as endangered or threatened under the Endangered Species Act. Possessing, transporting, or keeping a specimen of a listed species is illegal without a federal permit, even if you found it already dead. The Indiana bat, the northern long-eared bat, and the Virginia big-eared bat are among those currently protected.
Identifying a bat to species level can be tricky. Key features include the shape of the tail membrane, whether the tail extends past that membrane, how the wing membrane attaches to the hind leg, and whether a small spur on the ankle (called the calcar) has a visible ridge. Some species also have distinctive markings: the spotted bat, for instance, has three large white patches on its back. If you’re unsure what species you have, your state wildlife agency or a local university’s biology department can help with identification. Don’t begin preservation until you’re confident the species isn’t protected.
Choose a Preservation Method
There are two main approaches: dry preservation (similar to taxidermy) and wet preservation (storing the specimen in fluid). Dry preservation produces a displayable specimen with visible wing detail. Wet preservation keeps the tissue flexible and intact for long-term study but means the bat stays in a sealed jar.
Dry Preservation
Dry preservation works well for bats because their wings are thin membranes that dry relatively flat. You’ll need a flat piece of foam board or cork, stainless steel pins (regular steel pins will rust over time and stain the specimen), and a well-ventilated space.
Start by positioning the bat on the board while it’s still pliable. If the body has stiffened, you can relax it by placing it in a sealed container with a damp paper towel for several hours until the joints loosen. Spread the wings out to their full extent and pin them gently through the membrane near the edges, not through the delicate finger bones. Draw each wing forward carefully, pinning as you go to hold the position. Arrange the legs and ears so they’re visible and naturally positioned. The goal is to secure everything in place while the specimen air-dries, which typically takes one to three weeks depending on humidity.
Once fully dry, remove the pins. The specimen will be rigid and hold its shape. To prevent insect damage during storage or display, you can place it in a sealed shadow box or display case with a small amount of mothball or a pest strip designed for museum collections. Dermestid beetles (tiny scavenging insects found in most homes) will destroy an unprotected dry specimen within months.
Wet Preservation
Wet preservation involves two stages: fixing the tissue so it doesn’t decay, and then storing it in a long-term fluid.
The standard fixation fluid is 10% formalin (a diluted formaldehyde solution). This is a harsh chemical that requires gloves, eye protection, and good ventilation or outdoor use. Submerge the bat completely in the formalin solution. For a small bat, a few days to a week of fixation is sufficient. Larger specimens may need a small injection of the fixative into the body cavity to ensure the solution reaches internal tissues before they begin to break down.
After fixation, rinse the specimen thoroughly in running water for 24 hours to remove excess formalin. Then transfer it to its permanent storage fluid. The most widely used option is 70% ethyl alcohol (ethanol mixed with water). Isopropyl alcohol also works, at concentrations between 45% and 70%. Ethanol is the preferred choice for museum-quality specimens, but it can be expensive outside of institutional settings due to federal alcohol taxes. Isopropyl alcohol is cheaper and available at most pharmacies, though 70% isopropyl from the store works as a reasonable alternative.
Place the specimen in a glass jar with a tight-sealing lid, fully submerged. Check the fluid level every few months, as alcohol evaporates slowly even through sealed lids, and top it off as needed. Over time, the specimen will lose its natural coloring and take on a pale, uniform tone. This is normal.
Skipping Formalin: An Alcohol-Only Approach
Formalin can be difficult to source and unpleasant to work with. Many hobbyist collectors skip it entirely and fix their specimens directly in high-concentration alcohol. To do this, submerge the bat in 90% or higher ethanol (or the strongest isopropyl alcohol you can find) for the first two to four weeks. The high concentration pulls water from the tissues and acts as both fixative and preservative. After that initial period, transfer the specimen to 70% alcohol for long-term storage. This method is less precise than formalin fixation, and tissues may shrink slightly more, but it produces a stable specimen without requiring hazardous chemicals.
Preserving Wings Separately
If you’re primarily interested in the wing structure, you can preserve just the wings by carefully cutting them from the body at the shoulder joint. Pin them flat on a foam board, membrane fully spread, and let them air-dry completely. Dried bat wings are surprisingly durable and can be stored flat between sheets of acid-free paper, similar to how botanical specimens are pressed. A light coat of clear acrylic spray on both sides helps prevent the membrane from becoming brittle over time.
Long-Term Storage Tips
For dry specimens, the two biggest threats are pest insects and humidity. Store them in sealed containers with silica gel packets to control moisture. Keep them out of direct sunlight, which fades coloring and makes membranes brittle. For wet specimens, use glass jars rather than plastic, since alcohol degrades many plastics over time. Label every specimen with the date, location where it was found, and species identification if you have one. A small tag written in pencil on archival paper, placed inside the jar, is the standard museum approach since ink dissolves in alcohol but pencil graphite does not.