Sunday, May 30, 2010


 Bullfrogs (Rana catebeiana) are the largest frogs native to Missouri as well as in the rest of their range. They originally ranged from the Great Plains states, south to Texas, east to Central Florida. They were intentionally released in many Western States including California. This purposeful release was as a food source. The Red Leg frog in California was suffering a deep decline in numbers due to over harvesting. The bullfrog was released to compensate the reduction of numbers. Like what happens when most well meaning people release non-native species into new territories it poses a huge problem for native species, which is exactly what happened in California. Spadefoot toads, red-legged and yellow-legged frogs, young western pond turtles as well as native fish and even waterfowl chicks fall prey to this carnivorous frog.

The color of these frog can range from green, olive to brown. The hind legs are marked with distinct dark brown lines. The belly is white and the throat will have mottled gray appearance. Breeding males will have a yellow throat. The eardrums are visible on the side of their heads. The males have eardrums that are much larger than their eyes, the females have eardrums that are smaller or the same size as their eyes. These frogs range in size from 3 inches to 6 inches. The largest recorded bullfrog was over 8 inches in length (that's a lot of frog legs!). This frog is almost exclusively aquatic. They will be found in or near ponds, lakes, rivers, streams, wetlands, and sloughs. In years of drought their numbers may be greatly reduced. During years of heavy rains they will be seen crossing roads in large numbers.

 Bullfrogs are easily disturbed and will hop away if approached. Young bullfrogs will let out a "yelp" when jumping away. Breeding takes place in Missouri between Mid-May and Early July. Males will aggressively defend their territories during the mating season and will fend off other males by biting, mounting, kicking, bumping, or pushing other males. Large males can be heard on warm, balmy evenings singing loudly with a distinct  jug o' rum call. Several of these bullfrogs all singing at once can be a deafening chorus.....especially when planning a camping trip and they decide to sing loud and proud for the ladies. I've been awoken in the wee hours of the morning by their loud voices, crawled sleepily out of my tent and and flung whatever was handy at them. It effectively scares them away, only to have them return persistently to the same area over and over again! I can't help but feel that this is carrying "territorial" a bit far...can't they find ANOTHER side of the pond to sing from? One side is as good as the other right?

After mating, females are capable of laying up to 20,000 eggs. These eggs hatch and the young tadpoles will live in the water for 1 1/2 years before completing their life cycle. It will take another 2 to 3 years for them to reach adult size.

There was a study conducted in North Carolina that proved bullfrogs are resistant to the venom of the copperhead. To a lesser extent they were also immune to the venom of the cottonmouth.

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