The African ridgeback frogs are alive and well and being bred commercially for the pet store trade. They can get to 8 or 10 pounds. I had a young one once and it ate full grown mice!
Frogs have really big mouths, throats and stomachs and generally swallow their prey whole. It is really amazing what they can cram down their gullet! Over the years my students have dissected bull frogs and found in their guts: small fish, complete crayfish and a small snake, along with insects and occasionally fur. And bullfrogs aren't nearly as large as the African ridgebacks!