Wyoming’s wild beauty isn’t just about sweeping prairies and majestic mountains—it’s also a haven for some of North America’s most dangerous animals. Whether you’re hiking, camping, or just passing through, understanding which creatures pose the greatest risks can help you explore safely and responsibly. From stealthy predators to surprisingly dangerous farm animals, here are the top 10 most dangerous animals in Wyoming that you need to know about.
Top 10 Most Dangerous Animals in Wyoming
This list highlights creatures that pose the greatest risks based on their interactions with humans, potential for harm, and recent wildlife data.
1. Grizzly Bear
- Grizzly bears are found mainly in Yellowstone and Grand Teton National Parks, with around 700 estimated in Yellowstone alone.
- Weighing 200–700 lbs, these bears are strong, fast, and highly protective, especially of their young.
- Bear attacks on humans are rare, with about one per year in Yellowstone, but are often severe or fatal when they occur. Keep at least 100 yards away from any bear.
2. Mountain Lion
- Also called cougars or pumas, mountain lions are elusive but powerful predators weighing up to 200 lbs.
- They are stealthy ambush hunters, capable of leaping 15 feet high and 40 feet across.
- Attacks on humans are extremely rare but can be deadly. Stay in groups and remain alert, especially if you hear unusual noises in the wild.
3. Bison
- North America’s biggest land mammal, bison can weigh over 2,000 lbs.
- Despite their size, they can run up to 35 mph and become aggressive when approached.
- More people are injured by bison than bears in Yellowstone National Park each year. Stay at least 25 yards away.
4. Moose
- Moose are the largest member of the deer family, standing over 6 feet tall and weighing over 1,000 lbs.
- They are unpredictable—especially mothers with calves or males in the rut—and can charge suddenly.
- Trampling injuries are common when people get too close or surprise them.
5. Prairie Rattlesnake
- This venomous snake is Wyoming’s only native rattlesnake species and can grow up to 5 feet long.
- Its potent hemotoxic and neurotoxic venom can be fatal if not treated.
- Found in prairies, grasslands, shrublands, and forests, including elevations up to 9,500 feet.
6. Black Widow Spider
- One of the most venomous spiders in North America, black widows are found in garages, sheds, and woodpiles.
- Their neurotoxic venom can cause severe illness, especially in children and the elderly.
7. Wolves
- Gray wolves have been reintroduced to Wyoming and are crucial for ecosystem health.
- They rarely attack humans but are powerful pack hunters capable of inflicting serious injury if cornered or provoked.
8. Dog
- Surprisingly, domestic dogs cause more human injuries than most wild animals, due to bites and attacks.
- Each year, millions of dog bite incidents occur; the odds of dying from a dog bite are about 1 in 53,843—higher than fatal bear attacks!
9. Cow
- Cattle are responsible for over 20 deaths a year in the US from stomping, kicking, or crushing incidents.
- Many injuries occur when people work around livestock or underestimate their size and strength.
10. Ticks and Mosquitoes
- These tiny creatures can transmit dangerous diseases such as Lyme disease, Rocky Mountain spotted fever, and West Nile virus.
- While rarely deadly, they pose a greater risk to outdoor enthusiasts than most realize.
Dangerous Animals in Wyoming at a Glance
| Animal | Danger Level | Common Risk | Notable Fact |
|---|---|---|---|
| Grizzly Bear | High | Attacks if surprised/provoked | Around 700 in Yellowstone |
| Mountain Lion | High | Ambush predator | Can leap 40 ft |
| Bison | Medium | Charges when threatened | More injuries than bears in parks |
| Moose | Medium | Trampling, especially with calves | Tallest land mammal in Wyoming |
| Prairie Rattlesnake | High | Venomous bite | Only native rattlesnake |
| Black Widow | High | Neurotoxic bite | Live in dark, sheltered areas |
| Wolf | Moderate | Pack hunting, rare attacks | Protected species |
| Dog | Medium | Bites and attacks | More injuries than wild animals |
| Cow | Low | Crushing, trampling | Responsible for >20 deaths/year US-wide |
| Ticks & Mosquitoes | Medium | Disease transmission | Small but dangerous |
How to Stay Safe Around Dangerous Animals in Wyoming
- Keep a safe distance: At least 100 yards from bears and wolves; 25 yards from bison, moose, and other large animals.
- Avoid surprising wildlife: Make noise, especially in brushy or forested areas, to avoid startling animals like bears and mountain lions.
- Do not approach or feed wildlife: Wild animals are unpredictable and may see you as a threat.
- Store food securely: Bear-proof containers and following park guidelines reduce unwanted encounters.
- Wear long sleeves and pants: To protect against ticks and mosquitoes, especially in brushy areas.
- Supervise children and pets: Keep them close and under control in all wildlife areas.
Frequently Asked Questions
Which animal causes the most injuries in Wyoming?
Bison, domestic dogs, and even cows account for more human injuries each year than large predators like bears or mountain lions, mainly because they are more common and people often underestimate their strength and unpredictability.
Are bear attacks common in Wyoming?
No. Bear attacks are very rare. In Yellowstone, there is an average of only one bear attack per year among nearly 3 million visitors.
What should I do if I encounter a dangerous animal?
- Remain calm and do not run. Running may trigger a chase in predators like bears and mountain lions.
- Back away slowly and give animals a clear escape route.
- Carry bear spray when hiking in bear country.
Are any dangerous animals active year-round?
Bison, moose, dogs, and cows are active year-round. Bears hibernate in winter, and rattlesnakes are usually inactive during colder months, but ticks and mosquitoes become active in spring and summer.
Wyoming’s wilderness is stunning, but respect and caution are the best ways to ensure your adventures stay safe. Always observe wild animals from a distance, be prepared, and keep informed about changing wildlife conditions.