Megabat long, thus smaller than some microbats, for example, the Mauritian tomb bat. The largest attain a wingspan of , and weigh as much as . Most fruit bats have large eyes, allowing them to orient themselves visually in twilight and inside caves and forests. Their sense of smell is excellent. In contrast to the microbats, the fruit bats do not use echolocation (with one exception, the Egyptian fruit bat "Rousettus egyptiacus", which uses high-pitched tongue clicks to navigate in caves). Megabats make up the only family (Pteropodidae) in order Chiroptera that is not capable of laryngeal echolocation. Echolocation and flight
Type family versa. Type families are regarded as being generally easier to type-check than functional dependencies. Another advantage of associated types over functional dependencies is that the latter requires clients using the type class to state all of the dependent types in their contexts, including ones they do not use; since associated types do not require this, adding another associated type to the class requires updating only the class's instances, while clients can remain unchanged. The main advantages of functional dependencies over type families are in their added flexibility in handling a few unusual cases. Type family In computer science, a type