Wildlife of Yellowstone
Yellowstone holds nearly all its original large mammals — grizzly and black bears, gray wolves, mountain lions, bison, elk, moose, and bighorn sheep — plus geothermal features that support species found almost nowhere else. Lamar Valley is the world's best place to watch wolves in the wild.
Best timeMay – June for bear cubs and calving bison, September – October for the elk rut.
- 1Yellowstone reintroduced grey wolves in 1995 — now ~100 in 10 packs.
- 2The park sits on a supervolcano — hot springs feed unique microbes.
- 3Grizzlies emerge from dens as early as March.
Signature species
Curated for Yellowstone, each tagged with its IUCN Red List status.
- LC
Grey wolf
Canis lupus
- LC
Grizzly bear
Ursus arctos horribilis
- NT
American bison
Bison bison
- LC
Trumpeter swan
Cygnus buccinator
- LC
Wolverine
Gulo gulo
IUCN codes — EX extinct · EW extinct in wild · CR critically endangered · EN endangered · VU vulnerable · NT near threatened · LC least concern · DD data deficient
Dos & don'ts
Local etiquette that keeps wildlife wild.
Do
- Carry bear spray, not a firearm — spray is 3× more effective.
- Watch wolves in Lamar Valley at 6am.
- Keep distance — use zoom or binoculars, never bait animals closer.
- Stay on marked trails to avoid trampling nests, burrows and plants.
Don't
- Don't leave your car for a bison photo — they charge.
- Don't walk on thermal-basin crusts — deaths happen yearly.
- Never feed wildlife — human food changes behaviour and shortens lives.
- Don't share exact locations of nests, dens or rare species online.
Spotted here lately
Live from iNaturalist — research-grade observations within 80km, last 30 days.
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