North American Bullfrog
Missouri’s largest frog broadcasts a deep jug-o-rum from permanent water, where one missing pair of back folds separates it from the smaller Green Frog.
Artwork inspired by Frank Nuderscher
North American Bullfrogs are massive green, olive, or brown true frogs with a large round tympanum behind each eye and no dorsolateral folds running down the back. Adult males usually have an eardrum larger than the eye and may show a yellow throat; females generally have an eardrum near eye size.
Listen along permanent ponds, lakes, sloughs, and slow streams from spring into autumn. The resonant jug-o-rum may carry half a mile, with the strongest breeding choruses late at night. Use call, body size, tympanum, and absence of back folds together; never move frogs, tadpoles, bait, plants, or water between sites.
- Missouri role
- State amphibian and largest frog
- Decisive structure
- Large tympanum with no dorsolateral back folds
- Call
- Deep sonorous jug-o-rum from permanent water
Quick guide
- Listen before lighting
- Map callers from the low notes without walking the shoreline
- Separate Green Frog
- Green Frog is smaller and has a raised fold behind each eye
Separate Bullfrog from Green Frog without entering the pond edge
- Begin with the call
- Listen from a durable Missouri pond access for a deep jug-o-rum, especially on warm breeding-season nights.
- Check the eardrum and back
- Look for a very large frog with a conspicuous round tympanum and no dorsolateral folds extending down the back.
- Compare the Green Frog
- A North American Green Frog is smaller and carries a raised fold from behind each eye toward midbody.
- Protect permanent water
- Avoid soft emergent vegetation and clean footwear before visiting another Missouri wetland.
Good to know
Check the current Missouri Wildlife Code before capture: Bullfrogs are game animals with a regulated season and a combined limit with Green Frogs, even though observation itself is year-round.
Notice these
- Very large smooth-bodied frog
- Large round tympanum
- No dorsolateral back folds
- Deep jug-o-rum call