"Sabre bears are dangerous animals."
Translation:Ha'DIbaHmey Qob bIH mIl'oDmey'e'.
If you are using it as the subject in a "to be" sentence with a pronoun acting as the verb "to be" (bIH in this sentence) then in the standard dialect of Klingon, the -'e' is required. Leaving it off will make you sound like a rube.
As for the plural marker (-mey), it is fully optional and it won't sound particularly odd either with it or without it. If it's obvious from the context (like the use of the plural pronoun bIH) then it's probably more common to leave it off and the plural might sound slightly emphasized if you have it on, but it doesn't change the meaning or register at all and you won't sound like a rube either with it or without it.