The American bullfrogs native home range lies in the eastern part of North America from Canada to Florida. The bullfrog was introduced in BC in the early twentieth century because people wanted to farm it. Now it has spread throughout the Lower Mainland and Southern Vancouver Island with some reports in other areas of the province as well.
Bullfrogs can get quite big reaching up to 20 cm and weight 750g. When full grown they are a lot larger than most native frogs in BC. They are usually green or brown with large golden eyes and have a distinct tympanum ("ear") just below the eye.
Bullfrogs rarely leave the water for most of their life. They prefer to live in shallow, warm ponds and lakes with lots of vegetation. They can sometimes be found in ditches or slow streams but they prefer standing water.
What's the big deal?
Bullfrogs are aggressive eaters and will eat anything that can fit in their mouths! Since they have quite large mouths this means they will eat small mammals, birds, baby ducklings, fish, snakes, painted turtle hatchlings and of course other frogs. Bullfrogs don't have many predators and have a high reproductive rate making them able to establish quite quickly and easily in an area. Following the introduction and spread of the Bullfrog a few native species the Red-Legged frog and the Pacific Treefrogs both saw population declines in lakes and ponds with bullfrog presence. Bullfrog tadpoles also compete for food and habitat with native tadpoles which could contribute to low growth rates and survival of red-legged frogs, Pacific Tree Frogs and other native frog species.
You can help!
- Don't transport frogs from one place to another.
- Discourage children from keeping tadpoles as "pets".
- Don't put frogs or tadpoles in your backyards ponds. Instead try to encourage native frogs to your pond by creating an attractive environment with water, shelter and plenty of insects and food.
- If you see a Bullfrog a new bullfrog colony or have any concerns about Bullfrogs contact BC Frog watch.