Which animal hears without ears?

Newts and Salamanders

http://www.education.com/science-fair/article/hearing-ears/

Newts, salamanders and snakes all lack ears, yet can hear. But they are not animals. Harp, Leopard, Harbor and other types of seals lack pinnae, the portion of ears that stick out, so they appear to have no ears. They and other animals without pinnae have similar inner ear structure to other animals, and also very strong hearing.

Godwit wrote: "Newts, salamanders and snakes all lack ears, yet can hear. But they are not animals."

Newts, salamanders and snakes are definitely animals!

This site gives a reasonably accessible (although somewhat simplified) explanation of the current five-kingdom classification scheme:
1. Monera - single-celled organisms with no cell nucleus
2. Protista - single-celled organism with a cell nucleus
3. Fungi - multi-cellular organisms with no chloroplasts and no mechanism for movement; acquire nutrients by absorption
4. Plantae - multi-cellular organisms with chloroplasts which make nutrients through photosynthesis
5. Animalia - multi-cellular organisms with no chloroplasts which acquire nutrients by ingestion

http://www.ruf.rice.edu/~bioslabs/studies/invertebrates/kingdoms.html

Don't forget turtles and the rest of the reptile family.

Whales and dolphins (both are mammals) lack ears but must hear since they respond to sounds (in fact some speculate they navigate by echo-location like bats).

Most birds lack ear structures. The ones that seem to have them (owls) only have feather horns which may impact hearing ability but aren't considered ears.

https://en.wikipedia.org/wiki/Ears