Animals with no ear lobes can still hear sounds. Ear lobes are not necessary for hearing. The main structures responsible for hearing are the eardrum, the middle ear bones, and the inner ear. Ear lobes are simply the fleshy parts that hang down from the sides of the head. They do not play a role in the hearing process.
There are many animals that do not have ear lobes, such as cats, dogs, horses, cows, and pigs. All of these animals are able to hear sounds just fine. In fact, some animals with no ear lobes have even better hearing than humans. For example, dogs can hear sounds at much higher frequencies than humans can.