Are There Bullfrogs in North Dakota?
Bullfrogs are present in North Dakota but have a limited range restricted to the southern and eastern portions of the state. They are rare or absent in the northern Great Plains and western regions of North Dakota. Where bullfrogs do occur, they are found in permanent water bodies, typically in areas with slightly warmer microclimates and accessible freshwater.
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 present in North Dakota but have a limited range restricted to the southern and eastern portions of the state. They are rare or absent in the northern Great Plains and western regions of North Dakota. Where bullfrogs do occur, they are found in permanent water bodies, typically in areas with slightly warmer microclimates and accessible freshwater.
Where Bullfrogs Are Found in North Dakota
Bullfrogs in North Dakota occur primarily in the southern and eastern portions of the state where conditions are most favorable. The James River in south-central North Dakota provides habitat for bullfrogs in marshy sections and backwater areas. The Missouri River in south-central North Dakota has established bullfrogs in appropriate sections, particularly in slower-flowing areas with vegetation. The Des Lacs National Wildlife Refuge in northwestern North Dakota may have bullfrogs in suitable habitat. The Garrison Diversion wetlands in central North Dakota occasionally support bullfrogs. The Devils Lake region in north-central North Dakota has historically had bullfrogs in appropriate habitats. Otter Tail County marshes along the border with Minnesota may contain bullfrogs. The Red River valley wetlands in eastern North Dakota near the Minnesota border support bullfrogs in suitable locations. However, bullfrogs are sparse or absent over most of North Dakota, particularly in the western half of the state and areas above about 3,000 feet elevation. The short summers and long, intensely cold winters make it difficult for bullfrogs to establish outside the state's southern tier and eastern regions. TheNorth Dakota wildlife guideprovides information about habitats across the state. Seethe Bullfrog guide for North Dakotafor more.
Season and Timing in North Dakota
Bullfrogs in North Dakota have a compressed active season due to the state's cold climate. They emerge from hibernation very late in spring, typically not until May or even early June as water temperatures must reach 50 degrees Fahrenheit or higher. Calling activity begins in June and peaks in July and early August. The peak calling season is noticeably shorter than in warmer states, lasting perhaps six to eight weeks instead of three months. By late August or early September, calling activity decreases as water temperatures cool. Tadpole metamorphosis occurs from July through September, with most young frogs completing transformation by early fall. In October and even September in northern areas, bullfrogs retreat from active feeding and breeding. By November, all bullfrogs have entered hibernation in deeper water or thick mud. Winter dormancy lasts approximately six months, from November through April. This abbreviated active season leaves bullfrogs with limited time for reproduction, growth, and feeding. The short breeding window means bullfrogs in North Dakota must reproduce efficiently during the brief warm season. Year-round presence is impossible in most of North Dakota due to the frozen conditions lasting half the year.
How to Identify a Bullfrog
Bullfrogs are the largest frogs in North Dakota, typically reaching four to eight inches in body length. Adults may exceed eight inches in rare cases. Their skin is smooth and glossy, usually green or olive green with variable darker mottling on the back and sides. The underside is pale yellow or whitish, often with dusky markings or bars visible on the belly and legs. The tympanum, the large circular eardrum visible just behind the eye, is the most distinctive feature. In males, the tympanum is noticeably larger than the eye diameter, while in females it is roughly equal to the eye size. A prominent fold of skin runs along the head from behind the tympanum. The hind legs are large and muscular with fully webbed feet. During breeding season, males develop darker coloration and thickened forearms. Tadpoles are large and greenish, growing several inches before metamorphosis. The bullfrog's large size makes it unmistakable among North Dakota's few frog species. Learn more aboutNorth Dakota amphibiansto understand how these frogs survive in such a challenging climate.
Where Sightings Concentrate in North Dakota
Bullfrogs concentrate in specific water features in North Dakota where permanent freshwater and warmer conditions exist. The James River drainage, particularly around Jamestown and southward, supports bullfrogs in marshes and backwater sections. The Missouri River floodplain wetlands in south-central North Dakota provide habitat, especially in areas with emergent vegetation. The Garrison Diversion wetlands system, created through irrigation development, has become bullfrog habitat in areas with permanent water. Devils Lake, when water levels permit, supports bullfrogs around marshy shorelines. The Otter Tail River and associated wetlands near the Minnesota border contain bullfrogs. The Red River floodplain in eastern North Dakota supports bullfrogs in suitable locations. Protected marshes and wetlands in the Prairie Pothole region, when they retain permanent water, may harbor bullfrogs. Small lakes and permanent ponds in southern North Dakota occasionally contain bullfrogs. Large farm reservoirs and irrigation ponds in the south may support bullfrogs. However, bullfrogs are scattered and localized throughout North Dakota, never abundant except in the most favorable microhabitats. Most sightings occur in summer months when bullfrogs are active and calling. Explore thewildlife guideto find other amphibians adapted to North Dakota's extreme climate.
Typical Bullfrog Behavior
Bullfrogs in North Dakota follow behavior patterns similar to southern populations but must compress them into a shorter season. They are solitary and territorial, particularly males during the brief breeding season. Males are primarily nocturnal, hiding during daylight in or near water. At dusk during the short breeding season, males move to calling sites in shallow water or at the shoreline. They inflate their vocal sacs to produce the loud jug-o-rum call to attract females and warn rival males. Calling is most intense in July and early August. Males defend small territories from rival males. Bullfrogs are ambush predators that wait motionless for prey to approach closely enough to strike. They eat insects, spiders, crayfish, other frogs, small snakes, and occasionally young birds or small mammals. Tadpoles are aquatic and omnivorous, consuming algae, detritus, and small organisms. In North Dakota's short season, tadpoles may not complete metamorphosis in a single year, requiring two seasons to develop fully. This is called a two-year tadpole cycle. Bullfrogs are strong swimmers using powerful hind legs for propulsion and escape.
Coexistence and Legal Status in North Dakota
Bullfrogs are not native to North Dakota and were likely introduced from the south or west. They are not considered a controlled species and are generally legal to possess under North Dakota regulations. Check current North Dakota Game and Fish Department regulations before collecting any wildlife. Bullfrogs pose no danger to humans. They are not venomous and pose no direct threat. Bullfrogs are sometimes considered problematic in conservation contexts because they are voracious predators that consume native amphibian tadpoles and eggs. In North Dakota's limited amphibian diversity, bullfrogs may impact populations of native species where they are established. However, their limited range means impact is confined to specific water bodies. No widespread management programs target bullfrogs in North Dakota. Most populations remain unmolested as established species. If you encounter a bullfrog in North Dakota, approach quietly and slowly. The animal will likely retreat into water if threatened. Bullfrogs generally ignore humans unless directly captured or confined.
Species Often Confused with Bullfrogs
North Dakota has only a few frog species, which limits confusion with bullfrogs. The Northern Leopard Frog is the most common frog in North Dakota and might be confused with bullfrogs, but it is substantially smaller, typically two to three inches long, and has rounded spots rather than mottling. The Boreal Chorus Frog is tiny, usually less than one inch long. The Wood Frog occurs in northern areas and is much smaller than bullfrogs. The Great Plains Toad is common in North Dakota but is clearly different, with warty, bumpy skin and a squat build. The Northern Plains Spadefoot Toad, found in southwestern North Dakota, is smaller and has spades on hind feet. American Toads, where they occur, are clearly different with bumpy skin. Most confusion is unlikely given the bullfrog's substantially larger size compared to all other North Dakota frogs. If you see a large frog in North Dakota, it is almost certainly a bullfrog.
Frequently Asked Questions About Bullfrogs in North Dakota
Q: Are bullfrogs found throughout North Dakota? A: No, bullfrogs are limited to southern and eastern areas where permanent water and slightly warmer conditions exist. Much of western and northern North Dakota is too cold for established bullfrog populations. Q: What is that deep calling sound I hear at water bodies in summer? A: That is the call of a male bullfrog during breeding season. Bullfrogs are among the few frogs producing such loud, deep sounds. Q: Are bullfrogs native to North Dakota? A: No, bullfrogs are not native. They were likely introduced from southern states and have established in limited areas with suitable habitat. Q: Why are bullfrogs so rare in North Dakota compared to other frogs? A: Bullfrogs require long growing seasons and warm water. North Dakota's short summers and long, cold winters make it difficult for bullfrogs to complete their life cycle successfully across most of the state. Learn more about North Dakota's remarkable cold-adapted amphibians by visiting thewildlife hubto find how native frogs thrive in this extreme climate.
More places to see bullfrog
More wildlife in North Dakota