Sea lions are in the family Otariidae ("eared seals"), therefore they have external ears and hear stuff very much the same way we do. The family Phocidae ("earless seals") has no visible ears, but can still hear.

Seals are aquatic mammals. There are about 32 species of seals. There are two types of seals: the earless, or true, seals (family Phocidae); and the eared seals (family Otariidae), which are sea lions and fur seals. In addition to the presence of external ears, eared seals have longer flippers than earless seals.

Otariidae (sea lions and fur seals), Phocidae (true seals), and Odonobenidae (walruses).

Sea lions belong to the species Zalophus californianus. They are members of the Otariidae family, which also includes fur seals.

a fur seal is a type of seal. Fur seals are any of nine species of pinnipeds in the Otariidae family The true seals or earless seals are one of the three main groups of mammals within the seal suborder, Pinnipedia. All true seals are members of the family Phocidae. They are sometimes called crawling seals to distinguish them from the fur seals and sea lions of the family Otariidae. Seals live in the oceans of both hemispheres and are mostly confined to polar, sub-polar, and temperate climates, with the exception of the more tropical monk seals. - Wikipedia