Decomposing an animal to preserve its bones allows for educational exploration, natural history collections, or personal interest. This process uses natural biological mechanisms to clean skeletal remains. It involves guiding the body’s natural breakdown to isolate the durable bone structure. Understanding this process and the various methods to facilitate it can be a rewarding endeavor.
The Natural Decomposition Process
When an animal dies, its body immediately begins a transformation driven by biological and chemical factors. This process unfolds in stages: fresh, bloat, active decay, advanced decay, and dry/skeletonization. During the fresh stage, internal enzymes break down tissues (autolysis), and microbes in the gut multiply.
As microorganisms proliferate, they produce gases like methane and carbon dioxide, causing the carcass to swell, marking the bloat stage. This also attracts insects, such as blowflies, which lay eggs that hatch into maggots, accelerating tissue breakdown. The active decay stage involves significant tissue liquefaction as maggots and bacteria consume soft tissues, and fluids leak from the body.
In the advanced decay stage, most soft tissues are consumed, leaving tougher materials like skin, tendons, and cartilage. The dry or skeletal stage is reached when only bones, hair, and some dried tissues remain. Environmental factors like temperature, moisture, and the presence of scavengers or insects influence the speed of these stages. Warmer temperatures accelerate microbial activity, and sufficient moisture is necessary for decomposers to thrive.
Practical Decomposition Methods
Several methods can decompose an animal for bone collection, each with distinct advantages and considerations. The choice depends on the animal’s size, available space, and odor tolerance.
Burial
Burial uses soil microbes and insects to break down soft tissues. A shallow burial, 1-2 feet deep, promotes decomposition while minimizing odor. This low-maintenance method can take months to years, depending on soil conditions, temperature, and animal size.
Maceration
Maceration involves submerging the carcass or defleshed remains in water, allowing anaerobic bacteria to consume soft tissues. This process effectively cleans bones, especially smaller specimens. Maintaining a consistent water temperature optimizes bacterial activity. Maceration produces a strong, unpleasant odor due to anaerobic conditions, requiring a well-ventilated outdoor area.
Composting
Composting offers a contained and often faster alternative, creating a microorganism-rich environment. This method involves layering the animal carcass with carbon-rich materials like wood chips or leaves in an enclosed pile. Heat generated by microbial activity accelerates decomposition, with internal temperatures ideally reaching 49-71°C (120-160°F) to sanitize the material. Turning the pile regularly introduces oxygen, essential for most decomposers.
Dermestid Beetles
Dermestid beetles, also known as flesh-eating beetles, are specialized insects used by museums and taxidermists for bone cleaning. These beetles consume all soft tissues, leaving bones clean and intact. Setting up and maintaining a dermestid colony requires specific conditions, including controlled temperature, humidity, and a secure enclosure. This efficient method is typically reserved for those with dedicated facilities due to specialized care and potential for odor.
Safety and Legal Considerations
Handling animal remains requires adherence to safety protocols and legal regulations. Personal protective equipment (PPE) is essential to prevent exposure to potential pathogens and irritants. This includes wearing waterproof gloves, eye protection, and a respirator or mask to avoid inhaling airborne particles.
Hands should be washed with soap and water after any contact with the carcass or decomposition materials. Proper disposal of waste materials should follow local waste management guidelines. Animal carcasses can harbor bacteria such as Salmonella and E. coli, as well as viruses, so direct contact should be minimized.
Beyond personal safety, legal and ethical considerations are important when collecting animal bones. Identify the animal’s species, as regulations vary for wild versus domestic animals. Many jurisdictions have laws governing the collection of wild animal remains, especially for protected or endangered species, often requiring permits. Ensure the animal’s origin is from natural death or legal means, rather than hunting solely for bone collection.
Post-Decomposition Bone Preparation
Once decomposition removes most soft tissue, bones require further preparation for long-term preservation and aesthetic quality. The first step is degreasing, which removes residual fats and oils embedded within the bone structure. These lipids can cause bones to yellow and produce an unpleasant odor if not removed.
A common degreasing method involves soaking bones in warm water and mild dish detergent for weeks or months, depending on greasiness. Change the water regularly as it becomes cloudy with extracted grease. After degreasing, bones can be whitened.
Hydrogen peroxide is the preferred agent for whitening bones, as it brightens them without damage. Submerge bones in a hydrogen peroxide solution (3% to 12% concentration) for a few hours to a few days. Avoid household bleach, as it degrades bone structure, making it brittle and prone to flaking. After whitening, rinse bones and allow them to dry in a well-ventilated area before assembly or storage.