Preserving a bat requires choosing between two main approaches: wet preservation in alcohol for a lifelike, flexible specimen, or dry preservation using borax and salt for a lightweight display piece. Both methods work well for small mammals like bats, but each demands careful preparation, proper safety precautions, and the right materials to produce a specimen that lasts years or decades.
Check Your Local Laws First
Before handling any bat, confirm that possessing it is legal where you live. Several bat species are federally protected under the Endangered Species Act, and state wildlife agencies regulate possession of dead wildlife independently from federal law. In many states, you need a salvage permit or scientific collecting permit to legally keep a bat specimen. Contact your state fish and wildlife department to find out which species are protected and whether you need documentation. Keeping a federally protected species without authorization can trigger penalties under the Lacey Act, which prohibits possessing wildlife taken in violation of any state or federal regulation.
Safety When Handling a Dead Bat
Rabies is the primary concern. The virus can survive for extended periods in a dead animal’s carcass, so treat every bat as potentially infected regardless of how it died. Never handle a bat with bare hands.
Wear heavy work gloves, ideally gauntlet-length to protect your wrists and forearms. If you’re picking up a bat you’ve just found, place a thick plastic bag (4 mil or heavier) over the carcass and grab it through the bag, inverting the bag around the animal. This eliminates any chance of skin contact with saliva, blood, or tissue. Once you’re ready to begin preservation work, wear nitrile gloves, eye protection, and work in a well-ventilated area, especially if using any chemical fixatives.
Dry Preservation With Borax and Salt
Dry preservation, sometimes called mummification, is the simplest method and produces a lightweight specimen suitable for pinning, framing, or open display. It works particularly well for bats because of their small body mass and thin wing membranes.
Start by positioning the bat the way you want it to look when finished. Spread the wings open and pin them to a foam board or piece of cardboard if you want them displayed extended. You can also fold the wings against the body for a resting pose. Once positioned, pack borax generously over and around the entire specimen. If you prefer, mix borax and salt in roughly equal parts for faster moisture absorption. The borax acts as a desiccant and mild antiseptic, drawing moisture from the tissue while discouraging bacteria and insects.
Coat every surface thoroughly, paying extra attention to the body cavity and any folds in the wing membrane where moisture can linger. If the bat has a wound or open body cavity, pack the mixture directly inside. Place the whole setup in a dry, ventilated area away from pets and children. Drying typically takes several weeks depending on humidity levels and the size of the bat. You’ll know it’s done when the specimen feels completely rigid and lightweight, with no soft or pliable spots remaining.
Once dried, gently brush away excess borax with a soft paintbrush. The specimen will be brittle, so handle it carefully. Dried bats can be stored in shadow boxes, glass domes, or sealed display cases.
Wet Preservation in Alcohol
Wet preservation keeps the bat submerged in fluid, maintaining its three-dimensional shape, flexibility, and coloring better than dry methods over time. It’s the standard approach used in museum and university collections.
Fixing the Specimen
Before placing a bat in its long-term storage fluid, you need to fix the tissues to prevent decomposition from the inside out. For hobbyists, 70% ethanol works well as both a fixative and a long-term preservative, and it avoids the serious health hazards of formalin (a formaldehyde solution commonly used in professional labs). Research comparing the two methods has found that ethanol-fixed tissues show comparable preservation quality to formalin-fixed tissues, with some advantages in cellular detail.
To fix a small bat, inject 70% ethanol into the abdominal cavity using a syringe with a fine needle. A few small injections into the torso are enough for a bat-sized animal. This ensures the preservative reaches internal tissues before bacteria can break them down. Then submerge the entire specimen in 70% ethanol. Let it soak for at least one to two weeks at cool temperatures before transferring to fresh fluid for permanent storage.
Preparing the Storage Fluid
Your long-term storage fluid should be 70 to 75% ethanol. If you purchase high-concentration ethyl alcohol (around 95%), dilute it with distilled water to reach that range. Standard 40% isopropyl alcohol from a drugstore is too weak for long-term preservation. If you can find 99% isopropyl, you can dilute it to 70%, though ethyl alcohol is generally preferred for specimen work.
After the initial fixing period, transfer the bat to a clean jar with fresh 70% ethanol. The first batch of fluid will have absorbed water released from the specimen’s tissues, diluting the alcohol concentration. Replacing it ensures the preservative stays strong enough to prevent decay.
Choosing the Right Container
Container choice matters more than most people realize, especially for specimens meant to last years. Glass jars with screw-on polypropylene lids lined with Teflon are the gold standard, used by the National Park Service and natural history museums. These lids seal tightly and resist degradation from alcohol far better than alternatives.
Avoid metal lids, which corrode over time and allow the preservative to evaporate. Bakelite lids (the hard, black plastic caps found on some older jars) become brittle and spontaneously loosen with temperature changes. PVC plastic lids also degrade and should be skipped. If you can’t find polypropylene-lined lids, high-density polyethylene containers are an acceptable backup, though they’re more vulnerable to becoming brittle over time.
Acrylic display containers might look appealing, but they’re susceptible to cracking and allow oxygen to pass through the walls, which degrades the specimen and evaporates the fluid. Stick with glass for anything you want to keep long-term.
Protecting Your Specimen From Light
Both dry and wet specimens degrade when exposed to light, particularly ultraviolet radiation and direct sunlight. UV causes bleaching, yellowing, and structural weakening of organic materials like fur, skin, and wing membrane. Sunlight is the worst offender, but fluorescent and halogen bulbs also emit significant UV.
Store or display specimens away from windows and direct sunlight. If you want to illuminate a display, LED lights are your best option: they emit no UV or infrared radiation, so they won’t heat or bleach the specimen. For wet specimens in glass jars, keep them in a cabinet or shaded shelf when not being actively shown off. Polypropylene lids are themselves vulnerable to UV embrittlement, so even the container benefits from staying out of the light.
Ongoing Maintenance
Dry specimens need very little upkeep. Keep them in a sealed case to prevent insect damage (dermestid beetles and carpet beetle larvae will destroy an unprotected specimen), and check periodically for signs of pest activity like small holes or fine dust beneath the display.
Wet specimens require more attention. Check the fluid level every few months. Alcohol evaporates slowly even through a tight seal, and if the fluid drops below the specimen, exposed tissue will dry out and deteriorate. Top off with fresh 70% ethanol as needed. If the fluid becomes cloudy or discolored, replace it entirely. A well-sealed glass jar in a cool, dark location can hold a specimen for decades with only occasional fluid changes.