Are There Bullfrogs in Montana?
Bullfrogs are not native to Montana but have been introduced and are now established in scattered locations, particularly at lower elevations with warm water. They thrive in some farm ponds, warm-water lakes, and reservoir margins throughout the state. Finding bullfrogs in Montana requires knowing where these introduced populations persist.
By Tim, founder of Easy Street Markets. I maintain the wildlife database and verify every animal and source myself. Updated August 6, 2026.
Bullfrogs are not native to Montana but have been introduced and are now established in scattered locations, particularly at lower elevations with warm water. They thrive in some farm ponds, warm-water lakes, and reservoir margins throughout the state. Finding bullfrogs in Montana requires knowing where these introduced populations persist.
Where in Montana Bullfrogs Are Found
Bullfrogs in Montana are found primarily in the western and southwestern portions of the state, concentrated in lower-elevation areas with suitable water. Introductions have established populations in some private ponds and warm-water reservoirs in valleys. The areas around Missoula Valley and lower Flathead regions have reported bullfrog observations, as have portions of the Madison and Jefferson River systems. Warm-water lakes and man-made ponds in the Gallatin Valley near Bozeman occasionally support bullfrogs. However, their distribution is patchy and unpredictable compared to native frog species. Visit/wildlife/montanato learn about Montana's diverse native frog species that are better adapted to the state's cooler climate and higher elevations. Most of Montana's vast territory remains too cold for bullfrogs to establish thriving populations. Seethe Bullfrog guide for Montanafor more.
Season and Timing of Bullfrogs in Montana
Bullfrogs in Montana have a much shorter active season than in warmer states, typically calling from June through early August. Water temperatures must be warm enough to trigger breeding behavior, which generally doesn't occur until late spring in Montana's cooler climate. Males begin calling on warm evenings once water temperatures reach suitable levels, usually in late June. Tadpole development is slowed by cold water and shorter growing seasons, often taking more than one year in Montana conditions. By September, as water temperatures drop and nights become cool, bullfrogs retreat to deeper water or mud for dormancy. Winter conditions in Montana are extremely harsh for bullfrogs, and populations may suffer significant losses during particularly cold winters. Spring emergence is delayed compared to more southern states, sometimes not occurring until June. Check/wildlife/montana/bullfrogfor specific information about bullfrog locations in your area of Montana. Seethe Montana wildlife guidefor more.
How to Identify a Bullfrog
Bullfrogs are Montana's largest frog species, reaching four to eight inches in length, which makes them distinctive when compared to native Montana frogs. Their skin is smooth and typically green to olive-brown in color, sometimes with darker blotches. The large circular tympanum behind each eye is the most reliable identification feature, roughly equal in size to the eye itself. Males are generally larger than females and develop a prominent yellow throat during breeding season. Their powerful hind legs are noticeably muscular, built for jumping and swimming. The distinctive deep call sounds like 'jug-o-rum' or 'jug-o-roo,' an unmistakable sound that sets them apart from all other Montana frogs. Unlike some native Montana frogs, bullfrogs have smooth skin without prominent ridges or warts. Their overall useful appearance and size make positive identification relatively straightforward.
Where Bullfrog Sightings Concentrate in Montana
Bullfrogs in Montana concentrate in warm-water environments that are uncharacteristic of most of the state. Private farm ponds and livestock watering areas in lower valleys support populations when water remains warm throughout the summer. Some warm-water reservoirs and lakes maintained at higher temperatures than surrounding native waters harbor bullfrogs. The Flathead Lake region and lower valleys near it have documented populations. Warm thermal areas and geothermal springs in some regions can support bullfrogs. Most sightings occur on warm summer evenings near the water's edge in areas with emergent vegetation. Bullfrogs rarely venture far from water in Montana's arid climate, and they concentrate in the specific warm-water habitats that support them./wildlifeprovides information about visiting Montana's natural areas and respecting wildlife in their native habitats.
Typical Bullfrog Behavior in Montana
Bullfrogs in Montana exhibit the same hunting strategy as their populations elsewhere, sitting quietly at the water's edge and waiting for prey to approach. They feed on aquatic insects, smaller frogs, tadpoles, small crayfish, and occasionally small mammals or young birds. Males are territorial and establish calling sites that they defend vigorously against competing males during breeding season. Territorial interactions can be intense, with males wrestling and jumping aggressively at rivals. Bullfrogs in Montana are less active than in warmer climates due to the shorter season and cooler water temperatures. They tend to remain close to vegetation and structure that provides cover. When threatened, they make a startled croaking sound and leap away from danger. Their presence in Montana is often limited by the relatively short warm period, which affects growth rates and reproductive success compared to native Montana frog species.
Coexistence and Safety Notes
Bullfrogs in Montana are a concern to some wildlife managers because they are non-native predators that may compete with or prey upon native frog species. However, in Montana's cold climate, their populations remain limited and localized. Montana wildlife regulations protect native frogs, and bullfrogs are considered invasive in some contexts, though they rarely establish the dense populations seen in the Pacific Northwest. Handle any bullfrog with care, as their powerful legs and sharp teeth can cause injury if handled roughly. Bullfrogs are generally not aggressive toward humans but should be observed from a distance. Never deliberately transport bullfrogs between water bodies, as this introduces non-native species to new areas. Report any bullfrog sightings to the Montana Department of Fish, Wildlife and Parks to help track the species distribution. Their presence in Montana represents an ongoing ecological experiment with an uncertain long-term outcome.
Common Species People Confuse with Bullfrogs
The Columbia Spotted Frog is Montana's most colorful native frog but is much smaller than bullfrogs and lacks the large circular ear. The Northern Red-legged Frog is also smaller and has distinctive red coloration on its hind legs. The Oregon Spotted Frog, endangered in Montana, is small and spotted. The Pacific Tree Frog is Montana's most widespread native frog but is tiny compared to bullfrogs, reaching only 1.5 to 2 inches. The Tailed Frog, found in Montana's northern regions, is unusual with a small tail-like extension and lacks any resemblance to bullfrogs. The Northern Leopard Frog, found throughout Montana, is spotted rather than solid colored and has dorsal ridges that bullfrogs lack. The Great Plains Toad, while larger than most frogs, is an amphibian but calls differently and lacks the bullfrog's large ear. Familiarity with calls and physical features helps distinguish these native species from introduced bullfrogs.
Frequently Asked Questions About Bullfrogs
Q: Are bullfrogs supposed to be in Montana? A: No, bullfrogs are non-native and were introduced to the state. They were likely brought in for aquaculture or private use and established wild populations. Q: Should I remove bullfrogs if I find them? A: Do not attempt to remove bullfrogs yourself. Contact the Montana Department of Fish, Wildlife and Parks with location and details, and they will advise on appropriate actions. Q: Can bullfrogs survive Montana winters? A: Bullfrogs struggle in Montana's harsh winters and survival rates are low, limiting population spread. Most established populations rely on repeated introductions or warm-water refugia. Q: Why are bullfrogs not common in Montana? A: Montana's short summer, cool water temperatures, and harsh winters make survival and reproduction difficult for bullfrogs compared to the state's native frogs.
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