May 13, 2026
Protocol for Small Mustelid Carcass Collection, Handling, and Storage
- Andrin C. Dürst1
- 1University of Bern, Institute of Ecology and Evolution, Division of Conservation Biology, Bern, Switzerland
- Andrin C. Dürst: ORCID: https://orcid.org/0009-0004-8878-8994
Protocol Citation: Andrin C. Dürst 2026. Protocol for Small Mustelid Carcass Collection, Handling, and Storage. protocols.io https://dx.doi.org/10.17504/protocols.io.3byl469pogo5/v1
Manuscript citation:
Andrin C. Dürst 2026. Guidelines for Genetic Sample Collection of Small Mustelids. protocols.io
https://dx.doi.org/10.17504/protocols.io.eq2ly4wmplx9/v1
Otte, P.J., Carter, S.P., Dürst, A.C., Granata, M., Mos, J., Salvador, S., Valdez, V., Zub, K., Hofmeester, T.R. 2026. Too small to matter? A call to action for european small mustelid research. Mamm Res 71, 39 (2026). https://doi.org/10.1007/s13364-026-00860-2
License: This is an open access protocol distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Protocol status: Working
We use this protocol and it's working
Created: August 28, 2025
Last Modified: May 13, 2026
Protocol Integer ID: 225765
Keywords: mustelids, carcasses, genetic, sampling, mammal, conservation, carnivore, protocol for small mustelid carcass collection, storage of small mustelid carcass, small mustelid carcass collection, small mustelid carcass, documented carcass, reproducible research on small mustelid population, small mustelid population, tissue samples suitable for genetic analysis, tissue sample, instructions for safe collection, tissue sampling, weasel, standardized procedures for the collection, mustela erminea, pathogen screening, safe collection, reproducible research, storage this protocol, metadata recording
Disclaimer
Disclaimer: This document is a working protocol and is provided for informational purposes only. The author does not guarantee the accuracy, completeness, or appropriateness of the methods described for any specific context. Use of this protocol is at the user's own risk. The author accepts no responsibility or liability for any outcomes, errors, or consequences resulting from the use or misuse of this document. Users are solely responsible for ensuring compliance with applicable laws, institutional guidelines, and safety or ethical standards.
Abstract
This protocol provides standardized procedures for the collection, handling, and storage of small mustelid carcasses, including stoats (Mustela erminea), weasels (M. nivalis), and polecats (M. putorius). It includes instructions for safe collection, packaging, short- and long-term storage, tissue sampling, labelling, and metadata recording, while ensuring compliance with legal and ethical requirements.
Applying this protocol allows researchers, conservationists, and field collaborators to generate high-quality, well-documented carcass and tissue samples suitable for genetic analysis, morphological studies, pathogen screening, and other research applications. By following these guidelines, data and samples can be shared and compared across studies, supporting collaborative and reproducible research on small mustelid populations.
Image Attribution
Figure 1 & 2: author
Protocol thumbnail: ChatGPT
Guidelines
Introduction and scope
------------------------
The purpose of this protocol is to collect small mustelid carcasses primarily for genetic analysis. However, limiting the use of these carcasses to genetic analysis alone would represent a missed opportunity. Therefore, this protocol aims to be flexible and not exclude additional research applications. Some of these include:
- Genetic analysis (main goal)
- Contaminant screening (e.g., environmental pollutants)
- Morphological studies (e.g., body measurements, age, and sex determination)
- Stomach content and dietary analysis
- Disease surveillance and pathogen detection
This protocol complements the more general guidelines for genetic sample collection of small mustelids (see DOI: dx.doi.org/10.17504/protocols.io.eq2ly4wmplx9/v1) and provides detailed procedures specifically for carcass-based sample collection. The protocol focuses on small mustelids, specifically stoats (Mustela erminea), weasels (Mustela nivalis), and polecats (Mustela putorius). However, it can be applied to any other small mammal with similar biology and field conditions.
The intended users of this protocol are mainly field researchers and biologists, but it is also designed for use by government biologists, students, volunteers, game wardens, conservationists, and others who may find and collect carcasses. Involving a wide range of people increases the chance of collecting more samples. Especially people who spend a lot of time outdoors or near roads professionally or recreationally are likely to find carcasses and are therefore an important source of samples.
This protocol is written for a project in Switzerland, but it is kept flexible to apply to other countries. Users must consider and comply with local and national laws, including species protection status and permits required for collection and handling. For example, in Switzerland, stoats and weasels are protected under hunting law, requiring permission to collect carcasses. The development of this protocol was also motivated by increasing collaboration
among researchers working on small mustelids across Europe. This collaboration has been fostered through the European Weasel Gang (https://europeanweaselgang.eu/), an informal network that facilitates communication and coordination among researchers in this field.
Safety and ethical considerations
------------------------------------
Personal safety and hygiene:
● When collecting carcasses, always be aware of traffic risks, especially when handling roadkill. Use high-visibility clothing or vests if possible and exercise caution near roads.
● Always wear disposable gloves when handling carcasses to avoid direct contact with potentially infectious material. If gloves are unavailable, a plastic bag turned inside out can be used as an improvised glove.
● Use hand sanitizer after washing your hands to further reduce contamination risk.
● Avoid touching your face, eyes, or mouth during and
immediately after handling carcasses until your hands are properly cleaned.
● Never eat, drink, or smoke while handling carcasses.
● Do not store carcasses in any fridge or freezer that is also used for food or non-research purposes. Only use designated units.
Legal and permit requirements:
● Ensure you are aware of local and national laws regarding the collection of wildlife carcasses.
● Many small mustelid species, such as stoats and weasels, are protected by law, so permission is required to collect samples, even if the animal is already dead.
● The finder or collector might have to contact the responsible game warden or hunting department to obtain the
necessary permits before collection.
● If there is an intention to use the animal for taxidermy, an additional permit may be required from wildlife authorities.
● Always comply with regulations related to the transport, storage, and use of wildlife specimens.
Ethical considerations:
● Be respectful of local communities and landowners; obtain permission if accessing private land.
● Ensure data and samples are used responsibly and shared according to agreed-upon terms.
Roles and responsibilities
---------------------------
Finder / Collector:
- Locate carcasses in the field or elsewhere.
- Collect carcasses following safety and handling protocols.
- Record initial data including GPS coordinates, date, and condition.
- Transport or send carcasses to the local coordinator.
- Obtain any necessary collection permits (or in agreement with the coordinator).
Coordinator:
- Assign unique sample IDs.
- Receive carcasses and perform measurements (and tissue sampling).
- Manage storage of carcasses and tissue samples.
- Maintain the database and ensure metadata quality.
- Coordinate pathogen sampling if applicable.
Appendix A
-----------
| Entry | Implemented in DwC (or GGBN) | Definition (DwC if applicable) | Term URL (DwC or GGBN) | |
| materialSampleID | x | A unique identifier for a MaterialSample entity. | https://dwc.tdwg.org/terms/#materialSampleID | |
| sampleNumber | A unique numeric identifier assigned to each individual genetic sample within the study. Used to differentiate samples collected from the same individual or multiple individuals. Must be consistent across all records. | |||
| subsampleID | An optional identifier appended to the primary sampleNumber to denote subsamples or multiple sample types collected from the same individual. Represented by a lowercase letter suffix (e.g., a, b, c) in alphabetic order. | |||
| eventDate | x | The date-time or interval during which an Event occurred. | https://dwc.tdwg.org/terms/#eventDate | |
| country | x | The name of the country or major administrative unit in which the Location occurs. | https://dwc.tdwg.org/terms/#country | |
| decimalLatitude | x | Geographic latitude in decimal degrees, using the spatial reference system given in geodeticDatum. [WGS84 format preferred] | https://dwc.tdwg.org/terms/#decimalLatitude | |
| decimalLongitude | x | Geographic longitude in decimal degrees, using the spatial reference system given in geodeticDatum. [WGS84 format preferred] | https://dwc.tdwg.org/terms/#decimalLongitude | |
| coordinateUncertaintyInMeters | x | The horizontal distance (in meters) from the given decimalLatitude and decimalLongitude describing the smallest circle containing the whole of the Location. | https://dwc.tdwg.org/terms/#coordinateUncertaintyInMeters | |
| geodeticDatum | x | The ellipsoid, geodetic datum, or spatial reference system (SRS) upon which the geographic coordinates are based. | https://dwc.tdwg.org/terms/#geodeticDatum | |
| locationID | x | An identifier for the set of location information (data associated with dcterms:Location). | https://dwc.tdwg.org/terms/#locationID | |
| scientificName | x | The full scientific name, with authorship and date information if known. | https://dwc.tdwg.org/terms/#scientificName | |
| taxonCode | A standardized, unique alphanumeric code representing a species or taxonomic unit. The code is derived from the Latin scientific name by combining the first two letters of the genus name and the first two letters of the species name, with the first letter of each part capitalized (e.g., Mustela erminea → MuEr). | |||
| identificationCertainty | A qualitative or quantitative assessment of confidence in the taxonomic identification of the specimen or sample. Indicates whether the identification is confirmed, probable, tentative, or uncertain. (see list) | |||
| causeOfDeath | A description or coded term indicating the suspected or confirmed cause of death of the sampled individual (e.g., natural predation, roadkill, disease). | |||
| causeOfDeathCertainty | A statement or rating indicating the degree of certainty associated with the recorded cause of death, distinguishing between confirmed and assumed causes. (see list) | |||
| institutionCode | x | The name (or acronym) in use by the institution having custody of the object(s) or information referred to in the record. | https://dwc.tdwg.org/terms/#institutionCode | |
| recordedBy | x | A list of names of people, groups, or organizations responsible for recording the original Occurrence. | https://dwc.tdwg.org/terms/#recordedBy | |
| recordedByContact | Contact information (e.g., email, phone) for the person or team responsible for recording or collecting the sample, enabling follow-up communication if needed. | |||
| coordinator | The name or identifier of the project coordinator responsible for overseeing sample collection, metadata consistency, and data management across participating institutions. | |||
| coordinatorContact | Contact details (e.g., email address) of the project coordinator for coordination, troubleshooting, and communication purposes. | |||
| habitat | x | A category or description of the habitat in which the Event occurred. | https://dwc.tdwg.org/terms/#habitat | |
| locationRemarks | x | Comments or notes about the Location. | https://dwc.tdwg.org/terms/#locationRemarks | |
| materialSampleType | x | The nature of the material sample; preferably from a controlled vocabulary. | https://dwc.tdwg.org/terms/#materialSampleType | |
| preservationMethod | x | GGBN: Method used to preserve the material sample (e.g., ethanol 95%, frozen -80°C), from GGBN preservation vocabulary. | https://wiki.ggbn.org/ggbn/Ggbn:preservationType | |
| sampleCondition | A qualitative description of the physical condition of the sample at the time of collection or processing, including notes on degradation, contamination, or any abnormalities affecting sample quality. | |||
| measurementType_bodyLength | x | The linear distance from the tip of the snout to the base of the tail (excluding the tail). | https://dwc.tdwg.org/terms/#measurementType | |
| measurementValue_bodyLength | x | Value of bodyLength (im mm) | https://dwc.tdwg.org/terms/#measurementValue | |
| measurementUnit_bodyLength | x | Millimeters (mm) | https://dwc.tdwg.org/terms/#measurementUnit | |
| measurementType_tailLength | x | The linear distance from the base of the tail to its tip (not including the hair at the tip). | https://dwc.tdwg.org/terms/#measurementType | |
| measurementValue_tailLength | x | Value of tailLength (im mm) | https://dwc.tdwg.org/terms/#measurementValue | |
| measurementUnit_tailLength | x | Millimeters (mm) | https://dwc.tdwg.org/terms/#measurementUnit | |
| measurementType_bodyMass | x | The total mass (weight) of the animal measured using a precision scale. | https://dwc.tdwg.org/terms/#measurementType | |
| measurementValue_bodyMass | x | Value of bodyMass (in g) | https://dwc.tdwg.org/terms/#measurementValue | |
| measurementUnit_bodyMass | x | Grams (g) | https://dwc.tdwg.org/terms/#measurementUnit | |
| sex | x | The sex of the biological individual(s) represented in the Occurrence. | https://dwc.tdwg.org/terms/#sex | |
| furColour | Descriptive information about the coloration or pattern of the fur observed on the sampled individual, useful for phenotypic variation and identification. (see list) | |||
| comments | Additional comments and remarks. | https://dwc.tdwg.org/terms/#dynamicProperties | ||
| associatedMedia | x | A list of identifiers (publication, global unique identifier, URI) of media associated with the Occurrence. | https://dwc.tdwg.org/terms/#associatedMedia |
Table A.1: Metadata Fields, Definitions, and Standards.
If possible, entries should be recorded according to Darwin Core (DwC) or Global Genome Biodiversity Network
(GGBN) standard.
Materials
- Disposable gloves (recommended)
- Plastic bags (for packaging carcasses and can be used turned inside out as an improvised glove if needed)
- Second plastic bag (for double-bagging)
- Labels or waterproof notes to record sample metadata (e.g., sample ID, date, GPS coordinates)
- Hand sanitizer
- GPS device or smartphone capable of recording GPS coordinates (preferably in WGS84 format)
- Camera or smartphone for photographs of the carcass and surroundings
- Cool box or refrigerator (for short-term storage before transfer)
- Cool packs (ice packs) and/or insulated packaging (e.g., bubble wrap, multiple paper layers) for shipping
- Shipping boxes or mailers suitable for next-day courier delivery
- Unique label ID system or labels for assigning a unique label ID to each carcass (see section 3 for the ID system)
- Caliper (or vernier caliper) or measuring ruler for morphological measurements (body length and tail length)
- Straight ruler (metric) as shown in Fig. 1
- Tweezers/forceps
- Small scissors
- Scale for measuring body weight
- Scalpel (for tissue sampling)
- Sterilization supplies for tools (e.g., alcohol wipes, flame or autoclave where available)
- Screw-cap microcentrifuge tubes / screw-cap microtubes for tissue storage
- Ethanol (95-100%, note: >95% ethanol recommended for tissue samples; preferably 99%)
- Durable, waterproof and ethanol-proof labels (ethanol-proof labels)
- Pencil or ethanol-proof ink for writing labels (preferred over regular ink)
- Digital database or data management system for metadata storage (recommended)
- Excel template for metadata entry (an Excel template for metadata entry will be provided for uniform data collection and sharing)
- High-visibility clothing or vest (recommended for roadside collection)
Safety warnings
- Always wear disposable gloves when handling carcasses to avoid contamination and potential pathogen exposure. If gloves are unavailable, a plastic bag turned inside out can be used as an improvised glove.
- Use hand sanitizer after handling the carcass and before touching anything else. Wash your hands if possible.
- Be mindful of traffic safety when collecting roadkill; take appropriate precautions to avoid accidents. Use high-visibility clothing or vests if possible when working near roads.
- Carcasses may present infectious or hazardous material; handle with caution and follow institutional biosafety guidance.
- Freezing the carcass immediately after collection is discouraged if pathogen or disease analyses are planned, because freezing can destroy or reduce the viability of pathogens. Freezing should be considered only as a last resort if transfer is delayed and after consultation with the coordinator.
- If pathogen analysis is planned, collect pathogen/disease samples before freezing to preserve viability.
- Avoid thawing and refreezing cycles to maintain sample integrity.
- If the carcass is intended for taxidermy, take tissue samples in a way that will not be visible on the prepared specimen later on (e.g. tongue).
- Ensure labels are ethanol-proof.
- Keep tissue samples at -20 °C or lower for long-term preservation.
- Use of double-bagging and placement of a note with sample ID, collection date, and GPS coordinates alongside the sample reduces the risk of misidentification if labels become detached or mixed up.
- Avoid touching your face, eyes, or mouth during and immediately after handling carcasses until your hands are properly cleaned.
- Never eat, drink, or smoke while handling carcasses.
- Do not store carcasses in any fridge or freezer that is also used for food or non-research purposes. Only use designated units.
- Ensure you are aware of local and national laws regarding the collection of wildlife carcasses and obtain any necessary permits; contact the responsible game warden or hunting department if required.
Ethics statement
Users must consider and comply with local and national laws, including species protection status and permits required for collection and handling. For example, in Switzerland, stoats and weasels are protected under hunting law, requiring permission to collect carcasses.
Additional points from the protocol:
- Many small mustelid species are protected by law, so permission is required to collect samples, even if the animal is already dead.
- The finder or collector may need to contact the responsible game warden or hunting department to obtain necessary permits before collection.
- If animals are to be used for taxidermy, additional permits may be required from wildlife authorities.
- Always comply with regulations related to the transport, storage, and use of wildlife specimens.
- Be respectful of local communities and landowners; obtain permission if accessing private land.
- Ensure data and samples are used responsibly and shared according to agreed-upon terms.
Before start
- Bring and wear disposable gloves when handling carcasses to avoid contamination and potential pathogen exposure. If gloves are unavailable, bring a plastic bag that can be turned inside out and used as an improvised glove.
- Carry hand sanitizer and use it after handling carcasses and before touching anything else. Wash hands if possible.
- Carry a GPS device or smartphone to record GPS coordinates (WGS84 preferred) and a camera or smartphone to photograph the carcass and surroundings.
- Carry plastic bags for packaging carcasses and securing them with a knot.
- Be prepared to follow local and national legal requirements and any permits needed for collection.
- If possible, bring a cool box or means to keep the carcass cool (cool packs or access to a refrigerator) in order to store the carcass until transfer to the coordinator; samples should ideally be transferred the same day or overnight.
- Consider wearing high-visibility clothing or vests when working near roads or collecting roadkill.
- Do not store carcasses in any fridge or freezer that is also used for food or non-research purposes. Only use designated units.
Collection of carcasses
Sources of carcasses
Carcasses will most commonly be found opportunistic as:
- Roadkill
- Kills by domestic cats
- (By)catch in trapping activities
- Incidental finds during fieldwork or recreational activities
- Animals that died in wildlife care or rehabilitation centres
- Eradication programs
While roadkill and cat kills are expected to be the main sources, collectors should remain open to other sources or may plan active sampling (e.g. along roads).
Data collection and recording
When collecting carcasses, it is crucial to
record essential data. At a minimum, record:
- GPS coordinates of the find (preferably in WGS84 format)
- Date of collection
Additional useful data includes:
- Species identification and certainty of identification
- Cause of death (clearly state if assumed or confirmed)
- Condition of the carcass (fresh, decomposed, scavenged, etc.)
- Name and contact information of the finder/collector
- Notes about habitat and any other remarks
- Photographs of the carcass and surroundings (optional but recommended)
Safety and hygiene
- Always wear disposable gloves when handling carcasses to avoid contamination and potential pathogen exposure. If gloves are unavailable, a plastic bag turned inside out can be used as an improvised glove.
- Use hand sanitizer after handling the carcass and before touching anything else. Wash your hands if possible.
- Be mindful of traffic safety when collecting roadkill; take appropriate precautions to avoid accidents.
Packaging
- Place the carcass into a plastic bag and tie it closed with a secure knot.
- Place that bag into a second plastic bag and tie it closed as well. This double-bagging reduces the risk of contamination and leakage.
- Insert a label or note with the collected metadata (minimum: label ID, date, GPS coordinates) between the two bags to prevent sample misidentification if outer labels become damaged.
- Avoid reusing bags or containers from previous collections to prevent cross-contamination.
Short-term storage before transfer
If possible, keep the carcass cool in a cool box or refrigerator until it can be delivered to the local collection coordinator. This should be done on the same day or overnight.
Freezing the carcass immediately after collection is discouraged if there is any intention of conducting pathogen or disease analyses later because freezing can destroy or reduce the viability of pathogens.
If transfer to the collection point is delayed or not possible, freezing is the only alternative to prevent carcass degradation, but it should be considered a last resort after consultation with the coordinator.
Handling and initial processing at collection points
Receiving and transfer to the coordinator:
- The ideal situation is to have local collection points where carcasses can be brought for initial handling. Usually, this is managed by a person responsible for mustelid research in that area, hereafter called the coordinator.
- The coordinator may be responsible for a local or national collection effort.
Options to transport the specimen to the coordinator/collection:
- The finder or collector can bring the sample to the coordinator in person.
- The sample can be sent by mail or courier — if so, ensure the following:
Send packages in the afternoon just before the parcel drop-off deadline for next-day delivery.
Select the next-day delivery option to minimize transit time.
Do not send before the weekends to avoid waiting time in transit.
Use cool packs and/or insulated packaging (e.g., bubble wrap, multiple paper layers) to keep samples cool during shipping.
Confirm that the delivery address is correct and someone is available to receive the package (or a 24h accessible mailbox).
- If feasible, someone from the coordinator’s team can pick up the sample from the finder.
- Multiple local collection points (e.g., museums or vets) may be a possible solution to facilitate logistics in remote places.
Note
Note: If bringing or picking up samples, transporting them in a cool box is preferable, but if not possible, transport without cooling is acceptable if the time between collection and processing is short (e.g. a few hours).
Investigation and measurements of carcasses
Upon receipt, the coordinator or trained personnel will:
- Assign a unique label ID to the carcass (see section 3 for the ID system).
2. Take morphological measurements (see Fig. 1):
Figure 1: Example setup of the lab bench during morphological measurements and tissue sampling of small carnivore carcasses.
- Body length (excluding tail) [in mm]
- Tail length [in mm]
- Body weight [in grams]
3. Determine sex (male/female) and age class (juvenile, subadult, adult).
4. Conduct species confirmation if necessary.
Tissue sampling for genetic analysis
This is an ideal time to collect tissue samples (e.g. for genetic analysis), as it helps avoid repeated freezing and thawing later. Once sampling is complete, carcasses can be transferred to the freezer for long-term storage, while the tissue sample remains available for immediate or future use.
- Take a tissue sample for genetic analysis.
- For convenience and ease of access, cutting a piece of the tongue is recommended as it contains muscle tissue and is relatively easy to sample.
- If the tongue is not in good condition, alternative tissue sources include:
- Heart muscle (preferred tissue for genetic analysis, but less accessible).
- Back muscle (can be accessed through the ventral cavity, often less decomposed).
- Muscle from the hind leg.
- Toe clipping.
- Ear clipping.
- Use clean, sterilized tools (scissors, scalpel, forceps).
- Cut small pieces (e.g. minimum of 0.5–1 cm3) and immediately preserve.
- Preserve in ethanol (95–100%) using small containers (e.g. screw-cap microcentrifuge tubes).
- Check guideline for genetic sampling (Dürst 2025, DOI: dx.doi.org/10.17504/protocols.io.eq2ly4wmplx9/v1) of small mustelids for details on sampling and storing tissue.
Note
Important: If the carcass is intended for taxidermy, take tissue samples in a way that will not be visible on the prepared specimen later on (e.g. tongue).
Pathogen analysis (optional)
- If disease or pathogen analysis is planned, this is the appropriate time to take the necessary samples or hand the carcass to veterinary specialists.
- This must be done before freezing to ensure pathogen viability.
- Details of pathogen sampling are outside the scope of this protocol, but should be coordinated with veterinary or disease specialists.
Long-term storage
If no pathogen analysis is planned (or has been done), the carcass should be frozen for long-term storage.
Carcasses:
- Store frozen at a minimum of -20 °C. Colder temperatures (e.g., -80 °C) are preferable if facilities allow.
- Ensure carcasses are double-bagged with clear labelling on the outer bag, including sample ID, date, and location information.
- Avoid thawing and refreezing cycles to maintain sample integrity.
Tissue samples in ethanol:
- Store tissue samples in screw-cap microtubes filled with >95% ethanol (preferably 99%).
- Keep these samples at -20 °C or lower for long-term preservation.
- Ensure labels are ethanol-proof.
Database management:
- Maintain a secure, backed-up digital database with detailed metadata for all samples.
- Update the database whenever samples are moved, processed, or used in analyses.
Figure 2: Example of a carcass that is double-bagged, labelled, and prepared for storage in a freezer.
Note
Important: Use of double-bagging for carcasses and placement of a note with the sample ID, collection date, and GPS coordinates alongside the sample reduces the risk of misidentification if labels become detached or mixed up.
Labelling and sample identification system
To maintain consistency across all collections and enable easy tracking and data sharing,
use a standardized unique ID format:
[CountryCode]-[Year]-[InstitutionCode]-[TaxonCode]-[SampleType]-[SampleNumber][LetterSuffix]
| A | B | C | |
| Component | Description | Format / Rules | |
| CountryCode | Country of sample collection | 2-letter ISO 3166-1 alpha-2 code | |
| Year | Year of collection | 4 digits | |
| InstitutionCode | Code for the collecting or managing institution | Exactly 5 uppercase letters (complete with Xs if necessary) | |
| TaxonCode | Code for species or taxon, based on Latin name | 4 letters: 2 from genus + 2 from species (first letters uppercase) | |
| SampleType | Type of material collected | 3 uppercase letters | |
| SampleNumber | Unique identifier for the sample (=individual) | Exactly 4 digits (with leading zeros if necessary) | |
| LetterSuffix | Optional letter to indicate sub-samples from the same individual | 1 lowercase letter starting from a |
Example: CH-2025-NMBEX-MuNi-CAR-0071a
This represents:
- CH = Switzerland (ISO 3166-1alpha-2 country code)
- 2025 = Year of collection
- NMBEX = Institution code (e.g. Natural history museum of Bern, completed with an X)
- MuNi = Taxon code (e.g. Mustela nivalis)
- CAR = Sample type (e.g. carcass)
- 0071a = Sample number 71, subsample “a” (e.g. a carcass will most likely be the first sample taken)
Taxon code
Standardized codes for taxon codes include:
| A | B | C | |
| Common name | Scientific name | Taxon code | |
| Stoat | Mustela erminea | MuEr | |
| Least weasel | Mustela nivalis | MuNi | |
| European polecat | Mustela putorius | MuPu | |
| Long-tailed weasel | Mustela frenata | MuFr | |
| European mink | Mustela lutreola | MuLu | |
| American mink | Neogale vison | NeVi | |
| Pine marten | Martes martes | MaMa | |
| Stone marten | Martes foina | MaFo | |
| Red fox | Vulpes vulpes | VuVu | |
| Eurasian badger | Meles meles | MeMe | |
| Unspecified Mustela | Mustela sp. | MuSp | |
| ... | ... | ... |
Non-exhaustive list for taxon code.
Sample type abbreviations
Standardized codes for common sample types include:
| A | B | |
| Code | Sample type | |
| CAR | Carcass (whole) | |
| TIS | Tissue sample | |
| SCT | Scat (faeces) | |
| HAI | Hair | |
| SWB | Swab (oral/rectal) | |
| BLO | Blood |
Note
Note: Even though other sample types are not covered in this protocol, the ID structure is designed to accommodate additional types for completeness.
Suffixes for sub-samples:
When multiple samples of the same or different types are taken from a single individual, append a letter suffix (a, b, c, etc.) to indicate that they are subsamples from the same source (individual).
Labelling materials and practices:
- Use durable, waterproof and ethanol-proof labels.
- Preferably write labels with a pencil or ethanol-proof ink to ensure longevity in ethanol and freezing conditions.
- Make sure the metadata recorded in the database matches exactly the physical labels on the sample tubes and carcass bags.
- Include the sample ID, date and GPS coordinates on the label to ensure that, even in the case of an error or mix-up, the essential information remains linked to the specimen.
Metadata record
See Appendix A of the guidelines for genetic sampling of small mustelids for details and a complete list of metadata fields.
Alongside physical labelling (ID), maintain a digital database of all samples with detailed metadata fields including:
- Unique sample ID
- Date (and time) of collection
- GPS coordinates (WGS84)
- Species identification and certainty
- Cause of death (confirmed or assumed)
- Condition of the sample (carcass)
- Collector/finder name and contact
- Storage location (Institution)
- Morphometrics (Bodysize, Weight, Sex, etc.; if available)
- Comments and photos (if necessary)
An Excel template for metadata entry will be provided upon request for uniform data collection and easy sharing.
Protocol references
Check guideline for genetic sampling (DOI: 10.17504/protocols.io.eq2ly4wmplx9/v1) of small mustelids for details on sampling and storing tissue. See Appendix A of the guidelines for genetic sampling of small mustelids for details and a complete list of metadata fields.
This protocol has been mentioned in the following publication:
Otte, P.J., Carter, S.P., Dürst, A.C. et al. 2026. Too small to matter? a call to action for european small mustelid research. Mamm Res 71, 39 (2026). https://doi.org/10.1007/s13364-026-00860-2
Acknowledgements
The idea for developing these guidelines originated during the European Small Mustelid Meeting held in Groningen, the Netherlands. I am grateful to the participants of the meeting for the stimulating discussions and valuable feedback that shaped the development of the standardized sampling protocol. In particular, I would like to thank Stephen P. Carter, Marco Granata, Tim R. Hofmeester, Jeroen Mos, Pieter J. Otte, Salvador Salvador, Vasco Valdez, and Karol Zub for their constructive input and exchange of ideas.