Hippopotamus, 16 million years
Studies have confirmed that hippos are related to whales when it comes to mammals. The first definitive whales date back to around 53 million years ago, but hippos only 16 million years. The gap between the whales’ ancestors and hippos is about 40 million years.
You are right Amos, everything was created in 7 days by a magic man in the sky.
Carbon dating is not relevant here since it only can date thing that are 50000 years or younger. There are other methods for older things. The theory of evolution makes sense and can explain a lot of the observations that have been done by scientists.