What animal has the big tail?

This is a bit of a trick question! There are many animals with big tails, so it depends on what you mean by "big."

Here are a few examples:

* The biggest tail by length: The blue whale has the longest tail, reaching up to 20 feet long!

* The biggest tail by width: The sperm whale has the largest tail fin, which can be up to 15 feet wide!

* The biggest tail for its size: The peacock has a huge, elaborate tail made of feathers that it uses to attract mates.

To give you a better answer, can you tell me what kind of animal you're thinking of?