US Venomous Snake Clinical Reference — Foragers Edition

⚠ Medical Disclaimer: This guide is for educational purposes and field reference only. It does not replace professional medical advice, diagnosis, or treatment. In any suspected snakebite emergency, call 911 and contact Poison Control at 1-800-222-1222 immediately. Always follow the judgment of on-scene medical professionals.

Section 1 — Venom Classification Overview

🩸 HEMOTOXIC

Pit Vipers — all rattlesnakes, copperhead, cottonmouth

Mechanism: Phospholipases, proteases, hyaluronidase destroy tissue and coagulation cascade
Onset: Symptoms within 15–30 minutes; coagulopathy within 1–2 hours
DIC risk: Fibrinogen depletion, thrombocytopenia, elevated PT/PTT
Local signs: Rapid swelling, ecchymosis, hemorrhagic bullae, necrosis

⚡ KEY RULE: Do NOT wait for systemic symptoms before transport — local swelling alone is an indication for antivenom evaluation.

🧠 NEUROTOXIC

Coral Snakes — Micrurus species

Mechanism: Postsynaptic acetylcholine receptor blockade → descending flaccid paralysis
Onset: Delayed 1–12 hours; bite may appear minor with minimal local reaction
Latency trap: Patient feels fine for hours then deteriorates rapidly
Primary cause of death: Respiratory muscle paralysis

⚡ KEY RULE: Transport immediately even if patient feels completely fine. Airway management is priority — respiratory failure can occur hours after bite.

Section 2 — Species Clinical Cards

Hemotoxic — Pit Vipers

Rattlesnakes, Copperhead & Cottonmouth

All produce hemotoxic venom with local tissue destruction, coagulopathy, and systemic effects. CroFab or Anavip antivenom. Transport immediately — do not wait for systemic symptoms.

Western Diamondback Rattlesnake

Crotalus atrox

Hemotoxic — Pit Viper Southwest · Texas · Oklahoma · New Mexico · Arizona · California (desert)

Field Identification

Diamond pattern on back, black and white banded tail ('coontail rattler'), triangular head, heat-sensing pits between eye and nostril, rattle present. 3.5–5 ft average length.

Clinical Presentation

Immediate burning pain, rapid edema from bite site, ecchymosis within 30–60 min, hemorrhagic bullae, coagulopathy (fibrinogen depletion), thrombocytopenia, DIC in severe cases, hypotension, nausea, vomiting. Swelling can progress up entire limb within 2–4 hours.

Symptom Timeline

0–30 min: Local pain, swelling begins
1–2 hr: Edema spreading, early coagulopathy
2–6 hr: Bullae formation, systemic symptoms
6–24 hr: Peak coagulopathy, DIC risk

✓ Field DO

Call 911 immediately
Immobilize bitten limb at or below heart level
Remove rings, watches, tight clothing before swelling begins
Mark swelling edge with pen every 15 min, note time
Keep patient calm and still — movement accelerates venom spread
Note exact time of bite
Photograph snake from safe distance if possible (do NOT handle)
Transport to nearest emergency facility immediately

✗ Field DO NOT

No tourniquet — worsens necrosis and outcome
No incision at bite site — increases infection risk
No suction (Sawyer or mouth) — negligible venom removal
No ice or cold water — accelerates tissue damage
No alcohol — vasodilates, accelerates absorption
No aspirin/NSAIDs — worsens coagulopathy
No electric shock — no evidence, causes injury
No wait-and-see — transport even if patient feels fine

Hospital Management

CroFab (Crotalidae Polyvalent Immune Fab): Initial 4–6 vials IV in 250 mL NS over 60 min. Titrate to clinical response. Repeat 2-vial maintenance doses at 6, 12, 18 hr if coagulopathy recurs. Monitor CBC, PT/PTT, fibrinogen q2–4h.

Anavip (Crotalidae Immune F(ab')2): Approved 2015. 10 vials initial dose. Superior fibrinogen recovery, longer half-life. Less recurrent coagulopathy.

Timber Rattlesnake

Crotalus horridus

Hemotoxic — Pit Viper Northeast · Mid-Atlantic · Southeast · Appalachian forests · Midwest (southern)

Field Identification

Heavy-bodied, gray or yellow-brown with dark chevron crossbands, rust-colored dorsal stripe, black tail, rattle. 3–5 ft. Found in rocky ridges, hardwood forest, wetland edges — prime mushroom foraging terrain.

Clinical Presentation

Severe local pain and swelling, ecchymosis, coagulopathy. Southern 'canebrake' populations may cause myokymia, fasciculations, and neurologic symptoms in addition to hemotoxic picture (Mojave toxin variant). Myonecrosis in severe cases.

Symptom Timeline

0–30 min: Pain, early swelling
1–4 hr: Rapid edema, early coagulopathy
4–12 hr: Peak swelling, hemorrhagic bullae, systemic coagulopathy
2–6 hr (SE pop.): Neurologic symptoms (myokymia, fasciculations) possible in southern populations

✓ Field DO

Call 911 immediately
Immobilize bitten limb at or below heart level
Remove rings, watches, tight clothing before swelling begins
Mark swelling edge with pen every 15 min, note time
Keep patient calm and still — movement accelerates venom spread
Note exact time of bite
Photograph snake from safe distance if possible (do NOT handle)
Transport to nearest emergency facility immediately

✗ Field DO NOT

No tourniquet — worsens necrosis and outcome
No incision at bite site — increases infection risk
No suction (Sawyer or mouth) — negligible venom removal
No ice or cold water — accelerates tissue damage
No alcohol — vasodilates, accelerates absorption
No aspirin/NSAIDs — worsens coagulopathy
No electric shock — no evidence, causes injury
No wait-and-see — transport even if patient feels fine

Hospital Management

CroFab: 4–6 vials initial. For patients bitten in Southeast/Gulf states, monitor for neurotoxic signs (myokymia, fasciculations, neurologic symptoms). If neurotoxic signs present, consider higher initial dosing 6–8 vials. Note: neurotoxic component of canebrake venom is not well reversed by CroFab — supportive airway management may be needed.

⚠ Southern canebrake populations carry Mojave toxin variant — consider neurotoxic workup for any Southeast Timber Rattlesnake bite.

Prairie Rattlesnake

Crotalus viridis

Hemotoxic — Pit Viper Great Plains · Rocky Mountain foothills · MT · WY · CO · KS · NE · ND · SD

Field Identification

Greenish-brown to gray with rounded brown blotches, pale border on blotches, rattle. 2.5–4 ft. Common in open grasslands and prairie — frequently encountered by berry pickers and plant foragers.

Clinical Presentation

Moderate to severe local reaction, edema, ecchymosis, coagulopathy. Generally considered less severe than Western Diamondback but significant envenomations occur. Nausea, vomiting, hypotension in systemic cases.

Symptom Timeline

0–30 min: Local pain, swelling begins
1–3 hr: Progressive edema
3–12 hr: Coagulopathy develops, systemic symptoms

✓ Field DO

Call 911 immediately
Immobilize bitten limb at or below heart level
Remove rings, watches, tight clothing before swelling begins
Mark swelling edge with pen every 15 min, note time
Keep patient calm and still — movement accelerates venom spread
Note exact time of bite
Photograph snake from safe distance if possible (do NOT handle)
Transport to nearest emergency facility immediately

✗ Field DO NOT

No tourniquet — worsens necrosis and outcome
No incision at bite site — increases infection risk
No suction (Sawyer or mouth) — negligible venom removal
No ice or cold water — accelerates tissue damage
No alcohol — vasodilates, accelerates absorption
No aspirin/NSAIDs — worsens coagulopathy
No electric shock — no evidence, causes injury
No wait-and-see — transport even if patient feels fine

Hospital Management

CroFab: 4–6 vials initial IV over 60 min. Titrate to clinical response. Repeat maintenance dosing per protocol. Monitor CBC, PT/PTT, fibrinogen q2–4h.

Copperhead

Agkistrodon contortrix

Hemotoxic — Pit Viper Southeast · Mid-Atlantic · Northeast (southern) · Midwest · Texas · Oklahoma — most common venomous snakebite in eastern US

Field Identification

Hourglass-shaped copper-brown crossbands on tan/brown body, unmarked copper-colored head, no rattle. 2–3 ft. Found in rocky hillsides, leaf litter, stone walls, rotting logs — extremely common in mushroom foraging habitat.

Clinical Presentation

Immediate pain, local edema, ecchymosis. Rarely causes systemic coagulopathy or DIC. Myotoxicity reported. Most envenomations cause significant local tissue damage but are rarely fatal in healthy adults. Children and elderly at higher risk for systemic effects.

Symptom Timeline

0–30 min: Pain, swelling begins
1–4 hr: Edema spreads
4–24 hr: Peak local effects, ecchymosis, possible bullae. Systemic symptoms uncommon but monitor.

✓ Field DO

Call 911 immediately
Immobilize bitten limb at or below heart level
Remove rings, watches, tight clothing before swelling begins
Mark swelling edge with pen every 15 min, note time
Keep patient calm and still — movement accelerates venom spread
Note exact time of bite
Photograph snake from safe distance if possible (do NOT handle)
Transport to nearest emergency facility immediately

✗ Field DO NOT

No tourniquet — worsens necrosis and outcome
No incision at bite site — increases infection risk
No suction (Sawyer or mouth) — negligible venom removal
No ice or cold water — accelerates tissue damage
No alcohol — vasodilates, accelerates absorption
No aspirin/NSAIDs — worsens coagulopathy
No electric shock — no evidence, causes injury
No wait-and-see — transport even if patient feels fine

Hospital Management

CroFab: Indicated for progressive swelling, systemic symptoms, or significant coagulopathy. Many mild copperhead bites managed supportively without antivenom. If antivenom indicated: initial dose 4–6 vials. Observe minimum 8–12 hours. Copperhead bites frequently treated conservatively — but always transport for evaluation.

Note: copperhead is the most common venomous snakebite in eastern US and extremely common in mushroom foraging habitat (leaf litter, rotting logs, stone walls). Always transport — even 'mild' bites require evaluation.

Cottonmouth (Water Moccasin)

Agkistrodon piscivorus

Hemotoxic — Pit Viper Southeast · Gulf Coast · Mississippi Valley · Florida · Eastern Texas · Oklahoma · Virginia · Missouri — always near water

Field Identification

Heavy-bodied, dark brown to black, white cotton interior of mouth displayed as threat response (distinctive). Triangular head, heat-sensing pits. 2–4 ft. Found at water's edge — common near watercress, cattail, elderberry.

Clinical Presentation

Severe local tissue destruction, edema, hemorrhagic bullae, significant myonecrosis. Considered more cytotoxic than copperhead. Coagulopathy common. Systemic symptoms including hypotension, nausea, vomiting. High infection risk.

Symptom Timeline

0–30 min: Immediate severe pain, rapid swelling
1–3 hr: Hemorrhagic bullae, edema spreading rapidly
3–12 hr: Myonecrosis, coagulopathy, systemic symptoms

✓ Field DO

Call 911 immediately
Immobilize bitten limb at or below heart level
Remove rings, watches, tight clothing before swelling begins
Mark swelling edge with pen every 15 min, note time
Keep patient calm and still — movement accelerates venom spread
Note exact time of bite
Photograph snake from safe distance if possible (do NOT handle)
Transport to nearest emergency facility immediately
Get out of water immediately — secondary drowning risk during envenomation

✗ Field DO NOT

No tourniquet — worsens necrosis and outcome
No incision at bite site — increases infection risk
No suction (Sawyer or mouth) — negligible venom removal
No ice or cold water — accelerates tissue damage
No alcohol — vasodilates, accelerates absorption
No aspirin/NSAIDs — worsens coagulopathy
No electric shock — no evidence, causes injury
No wait-and-see — transport even if patient feels fine

Hospital Management

CroFab: 4–6 vials initial; higher doses may be needed for severe envenomations. Fasciotomy rarely indicated — avoid unless confirmed compartment syndrome with measured pressures >30 mmHg. Wound care critical due to high infection risk.

Neurotoxic — Coral Snakes

Micrurus Species — Eastern & Texas Coral Snakes

Bite may appear trivial. Critical latency trap: patient feels fine for hours then deteriorates rapidly. Transport immediately even without symptoms. Antivenom supply is limited — contact Poison Control at once.

Eastern Coral Snake

Micrurus fulvius

Neurotoxic — Coral Snake Southeast — Florida · Georgia · South Carolina · North Carolina · Mississippi · Alabama · Louisiana

Field Identification

Bright red, yellow, and black bands — RED TOUCHES YELLOW (kills a fellow). Distinguished from harmless scarlet kingsnake by band order. Small head, round pupils, 20–30 inches. Secretive — found under leaf litter and logs, prime mushroom habitat.

Clinical Presentation

Bite may appear trivial — small punctures, minimal local reaction, no significant swelling. Patient may feel completely fine for 1–12 hours. Then: descending flaccid paralysis, ptosis, diplopia, dysarthria, dysphagia, respiratory muscle paralysis. Respiratory failure is the cause of death. Once paralysis begins it is extremely difficult to reverse even with antivenom.

Symptom Timeline

0–2 hr: Minimal symptoms — false reassurance period
2–6 hr: Cranial nerve palsies begin: ptosis, diplopia
6–12 hr: Bulbar symptoms: dysarthria, dysphagia
12–24 hr: Respiratory failure risk — mechanical ventilation may be required

✓ Field DO

Call 911 immediately
Immobilize bitten limb at or below heart level
Remove rings, watches, tight clothing before swelling begins
Mark swelling edge with pen every 15 min, note time
Keep patient calm and still — movement accelerates venom spread
Note exact time of bite
Photograph snake from safe distance if possible (do NOT handle)
Transport to nearest emergency facility immediately
CRITICAL: transport immediately even if patient feels completely fine — do not wait for symptoms
Airway equipment should be ready en route

✗ Field DO NOT

No tourniquet — worsens necrosis and outcome
No incision at bite site — increases infection risk
No suction (Sawyer or mouth) — negligible venom removal
No ice or cold water — accelerates tissue damage
No alcohol — vasodilates, accelerates absorption
No aspirin/NSAIDs — worsens coagulopathy
No electric shock — no evidence, causes injury
No wait-and-see — transport even if patient feels fine

Hospital Management

North American Coral Snake Antivenin (Wyeth): Manufacturer discontinued — LIMITED SUPPLY. Contact Poison Control (1-800-222-1222) for current availability and nearest stockpile location.

Dose: 3–5 vials IV if envenomation confirmed or strongly suspected. Administer prophylactically — do not wait for neurologic symptoms. Once paralysis begins antivenom is less effective.

Mechanical ventilation may be required for days to weeks. No FDA-approved alternative currently available in US — clinical trials ongoing.

⚠ CRITICAL LATENCY TRAP: patient appears fine for 1–12 hours then deteriorates rapidly. Prophylactic antivenom is recommended — do not wait for symptoms. Airway is the priority.

Texas Coral Snake

Micrurus tener

Neurotoxic — Coral Snake Texas · Western Louisiana · Arkansas (southern) · Oklahoma (southeastern)

Field Identification

Same red-yellow-black banding as Eastern Coral Snake — RED TOUCHES YELLOW. Slightly smaller, 20–24 inches. Found in dry rocky areas, wooded hillsides, and brush — different habitat than Eastern Coral Snake.

Clinical Presentation

Same neurotoxic presentation as Eastern Coral Snake — descending flaccid paralysis, respiratory failure. Same latency trap — bite appears minor, patient deteriorates hours later.

Symptom Timeline

0–2 hr: Minimal symptoms — false reassurance period
2–6 hr: Cranial nerve palsies begin: ptosis, diplopia
6–12 hr: Bulbar symptoms: dysarthria, dysphagia
12–24 hr: Respiratory failure risk — mechanical ventilation may be required

✓ Field DO

Call 911 immediately
Immobilize bitten limb at or below heart level
Remove rings, watches, tight clothing before swelling begins
Mark swelling edge with pen every 15 min, note time
Keep patient calm and still — movement accelerates venom spread
Note exact time of bite
Photograph snake from safe distance if possible (do NOT handle)
Transport to nearest emergency facility immediately
CRITICAL: transport immediately even if patient feels completely fine
Airway equipment should be ready en route

✗ Field DO NOT

No tourniquet — worsens necrosis and outcome
No incision at bite site — increases infection risk
No suction (Sawyer or mouth) — negligible venom removal
No ice or cold water — accelerates tissue damage
No alcohol — vasodilates, accelerates absorption
No aspirin/NSAIDs — worsens coagulopathy
No electric shock — no evidence, causes injury
No wait-and-see — transport even if patient feels fine

Hospital Management

Same antivenom supply crisis as Eastern Coral Snake. Contact Poison Control (1-800-222-1222) immediately for current availability. Anascorp (centruroides scorpion antivenom) does NOT cross-react — do not substitute. Supportive mechanical ventilation may be needed for days to weeks.

⚠ Same critical transport urgency as Eastern Coral Snake. Prophylactic antivenom even before symptoms develop. Airway management is priority.

Section 3 — Regional Distribution

Region	Species Present
Northeast	Timber Rattlesnake, Copperhead
Mid-Atlantic	Timber Rattlesnake, Copperhead, Cottonmouth (southern)
Southeast	Timber Rattlesnake, Copperhead, Cottonmouth, Eastern Coral Snake
Florida	Cottonmouth, Eastern Coral Snake, Dusky Pygmy Rattlesnake
Gulf Coast	Cottonmouth, Eastern Coral Snake, Western Diamondback (western)
Midwest	Timber Rattlesnake (southern), Copperhead (southern), Prairie Rattlesnake (western)
Great Plains	Prairie Rattlesnake
Southwest	Western Diamondback, Prairie Rattlesnake
Texas	Western Diamondback, Copperhead, Cottonmouth, Texas Coral Snake
Pacific Northwest	Western Rattlesnake (Crotalus oreganus — not covered in this guide)
Rocky Mountains	Prairie Rattlesnake

Section 4 — Universal Field Response Protocol

🐍 Field Response — ALL Venomous Snakebite

✓ DO

Call 911 or Poison Control (1-800-222-1222) immediately
Stay calm and keep patient as still as possible — movement accelerates venom spread
Immobilize bitten limb at or slightly below heart level
Remove rings, watches, tight clothing, and footwear from bitten limb before swelling begins
Mark leading edge of swelling with pen every 15 minutes with time noted
Note exact time of bite
Photograph snake from safe distance if possible — do NOT handle it (dead snakes can envenomated via reflex bite for up to 1 hour)
Transport to nearest emergency facility immediately — do not drive yourself

✗ DO NOT

No tourniquet — concentrates venom, causes necrosis, worsens outcome
No incision at bite site — increases infection, does not remove venom
No suction (Sawyer extractor or mouth) — negligible venom removal, increases infection
No ice or cold water — causes additional vasoconstriction and tissue damage
No alcohol — vasodilates, accelerates venom absorption
No aspirin or NSAIDs — worsens coagulopathy
No electric shock — no scientific basis, causes additional injury
No wait-and-see — transport immediately even if patient feels fine (especially coral snakes)

Poison Control: 1-800-222-1222 — 24/7, free, expert guidance

Section 5 — Hospital Management & Antivenom Protocols

CroFab® — Crotalidae Polyvalent Immune Fab

Pit Viper Antivenom (rattlesnakes, copperhead, cottonmouth)

Indications

Progressive local swelling, coagulopathy, systemic symptoms

Initial Dose

4–6 vials IV in 250 mL NS over 60 minutes

Response Endpoint

Arrest of local progression, correction of coagulopathy, improvement of systemic symptoms

Maintenance

2 vials IV at 6, 12, and 18 hours after initial control achieved

Lab Monitoring

CBC, PT/PTT, INR, fibrinogen, BMP every 2–4 hours for first 24 hours

Recurrent Coagulopathy

May occur 2–14 days post-envenomation — outpatient follow-up essential

Anavip® — Crotalidae Immune F(ab')2

Alternative Pit Viper Antivenom — FDA approved 2015

Initial Dose

10 vials IV

Advantages

Longer half-life, superior fibrinogen recovery in clinical trials, less recurrent coagulopathy vs CroFab

Recurrent Coagulopathy

Less common than with CroFab due to longer half-life

North American Coral Snake Antivenin (Wyeth)

Neurotoxic Coral Snake Antivenom — LIMITED SUPPLY

⚠ SUPPLY CRISIS: Wyeth discontinued production. Contact Poison Control (1-800-222-1222) immediately for current availability and nearest stockpile location.

Dose

3–5 vials IV if envenomation confirmed or strongly suspected

Timing

Administer prophylactically — do NOT wait for neurologic symptoms. Once paralysis established, antivenom is less effective.

Supportive Care

Airway management is priority. Mechanical ventilation may be required for days to weeks. No reversal agent once paralysis established.

Alternative

No FDA-approved alternative currently available in US. Clinical trials ongoing. Anascorp does NOT cross-react.

Section 6 — Myth Busting

Myth	Reality
Cut and suck out the venom	No evidence of efficacy; creates infection risk, delays transport
Tourniquet stops venom spread	Concentrates venom locally, causes tissue necrosis, worsens outcome
Alcohol neutralizes venom	Vasodilation accelerates venom absorption into bloodstream
Ice slows venom	Cold causes additional vasoconstriction and tissue damage
Electric shock deactivates venom	No scientific basis; causes burns and additional injury
Dead snake is safe	Decapitated snake heads can envenomated by reflex bite for up to an hour
Small snake = less dangerous	Juvenile rattlesnakes can deliver full venom loads
Coral snakes are not dangerous	Most lethal US snake by venom toxicity; bite appears minor then causes respiratory failure
Sawyer pump removes venom	Clinical studies show negligible venom removal, increases infection risk
Running helps dilute the venom	Activity increases heart rate and accelerates systemic venom spread

Section 7 — Veterinary — Dogs in the Field

🐕 Dogs Are Frequent Snakebite Victims While Foraging with Owners

Key Differences from Human Envenomation

Dogs are bitten on face and nose most often — rapid facial swelling, airway compromise risk
Much smaller body mass — venom dose per kg is higher; smaller dogs have worse outcomes
Copperhead bites most common in eastern US dogs

Symptoms to Watch For

Rapid facial swelling, yelping, drooling, lethargy, collapse

Field Response

Immediate transport to veterinary emergency
Carry your dog if possible — do not let them walk
Keep dog as calm and still as possible
Do NOT apply tourniquet or ice

Veterinary Treatment

Antivenom is available for dogs — Crotalidae Polyvalent Immune Fab (same as CroFab, FDA approved for veterinary use). Dog survival rates are high with prompt treatment. Delay is the primary risk factor for mortality.

Section 8 — Forager-Specific Encounter Scenarios by Terrain

🌲 Woodland / Forest Foraging (mushrooms, ramps, fiddleheads)

Primary Species

Timber Rattlesnake, Copperhead

Risk Behavior

Reaching into leaf litter, lifting logs and rocks, stepping over logs without looking, kneeling near rock outcroppings

Prevention

Wear leather boots above ankle; use a walking stick to probe ahead; never reach into a space you cannot see

🌾 Grassland / Prairie Foraging (berries, roots, greens)

Primary Species

Prairie Rattlesnake, Western Diamondback (southern)

Risk Behavior

Walking through tall grass without watching foot placement, sitting on the ground

Prevention

High boots, gaiters, snake chaps in high-risk areas; shuffle feet through grass rather than stepping high

💧 Waterside Foraging (watercress, cattail, elderberry)

Primary Species

Cottonmouth, Eastern Coral Snake (Southeast)

Risk Behavior

Reaching into water vegetation, stepping on muddy banks, reaching under overhanging vegetation at dusk

Prevention

Never reach into vegetation at water's edge without looking; probe with a stick first; be extra cautious at dusk when cottonmouths are most active

⛰️ Rocky Terrain / Hillside Foraging (morels, ramps, medicinal plants)

Primary Species

Western Diamondback, Timber Rattlesnake, Prairie Rattlesnake

Risk Behavior

Stepping on rocks without looking, reaching into rock crevices, sitting on warm rocks

Prevention

Look before you step on any rock; never put hands in rock crevices; snakes thermoregulate on warm rocks in the morning

🍂 Leaf Litter / Rotting Log Areas (mushrooms, truffles)

Primary Species

Copperhead, Eastern Coral Snake, Cottonmouth (Southeast)

Risk Behavior

Lifting logs and debris with bare hands

Prevention

Always flip logs away from you with a stick; wear gloves; look before kneeling; coral snakes are especially common under logs and leaf litter

🐍 Emergency? Poison Control: 1-800-222-1222 — 24/7, free, expert snakebite guidance

Photo credits: All species photographs sourced from iNaturalist under Creative Commons license (CC BY-NC). Taxonomy per iNaturalist research-grade observations.