Field forensics
Field Necropsy Guide
When reptiles are found dead in the field, timely necropsy preserves evidence. This guide covers safety, documentation, sampling, and chain of custody so labs can detect causes of death and inform conservation or husbandry changes.
Use cases:
Stranding events, roadkill surveys, unexplained mortalities.
Kit:
Gloves, scalpel, forceps, sample vials, fixatives, camera, labels, PPE.
Safety & setup
Work with gloves and eye protection; assume pathogens are present. Set up a clean tarp or table. Position the animal for photos before incisions. Note carcass condition (fresh, moderately decomposed, advanced), which dictates which samples are viable. Keep shade/cool if ambient heat is high to slow decomposition.
Documentation
Record GPS, date/time, finder, and circumstances (found on road, near water, signs of trauma). Take dorsal, ventral, and close-up photos of lesions or trauma. Assign a unique ID and label all bags and vials. Note odors, parasites visible, and any unusual fluids.
External exam
Check eyes, mouth, nares, vent, shell/scales for lesions, fractures, or discharge. Measure length, weight (if possible), and sex when discernible. Swab mouth/cloaca for PCR if disease is suspected (ranavirus, herpesvirus, mycoplasma).
Internal exam & sampling
Make a midline incision; reflect skin and muscle. Inspect organs for discoloration, hemorrhage, masses. Collect tissues: liver, kidney, spleen, lung, GI, and any lesions. Split samples—fresh/frozen for culture/PCR, fixed (10% buffered formalin) for histology. For turtles, collect bone/shell if metabolic disease suspected. Avoid cross-contamination between organs; use clean tools or flame/ rinse between samples.
Special samples
- Stomach contents for diet/toxin clues.
- Blood (if fresh) via heart/major vessels; store in EDTA/heparin.
- Parasites: preserve whole worms/arthropods in alcohol; note location.
- Environmental: water/soil near carcass if contamination suspected.
Chain of custody & shipping
Log every transfer; keep samples labeled and chilled/frozen as required. Ship with ice packs or dry ice per regulations; include paperwork (permit numbers, case info, sample list). Communicate with the lab so they expect the shipment and know the suspected issues.
Biosecurity & disposal
Disinfect tools and surfaces after use; bag disposable items. Dispose of carcasses per local rules (deep burial, incineration) to prevent scavenger exposure or pathogen spread. If legal requirements exist for protected species, follow agency guidance for retention or return.
Reporting
Summarize findings with photos, maps, and sample list. Note limitations (decomposition, limited tools) and next steps. Share reports with stakeholders (agencies, landowners, researchers) and feed results into monitoring databases. Timely communication turns single necropsies into actionable patterns.
Storage & transport
If immediate lab submission isn’t possible, refrigerate fresh carcasses (not frozen unless instructed) and keep samples chilled/frozen per lab guidance. Use secondary containment to prevent leaks. Label coolers clearly and include a sample inventory. Ship early in the week to avoid weekend delays.
Quick checklist
- Photo, GPS, ID assigned; carcass condition noted.
- External exam done; measurements recorded.
- Key tissues collected: liver, kidney, spleen, lung, GI, lesions; split fresh/fixed.
- Swabs/parasites/environmental samples taken if indicated.
- Chain of custody logged; tools disinfected; carcass disposed per rules.
A disciplined field necropsy preserves evidence and speeds answers when time in the field is tight.