^one of the eternal mysteries of language. I've always been wondering why there are hives of bees but swarms of mosquitos, flocks of birds but paddlings of ducks, packs of wolves but bands of coyotes, herds of deer but a mob of kangaroohs? Couldn't there simply be groups of insects/birds/fish/mammals?
And if fish in general come in schools, why don't large fish form a university or at least a college? And wouldn't a bed of clams be rather uncomfortable?
Because language is more fun when we can say “Murder of crows” and “Unkindness of ravens”.