Why do vampires hiss? nt

[raccoon]

[sl8]

1. You're not the only one that wants to know.

[Laffy Kat]

3. Miss that show so much.

[LunaSea]

2. Because if they barked...

We'd just laugh.

[The Velveteen Ocelot]

5. LOL!

[Dave Starsky]

13. Ha ha. That's hilarious.

I never thought about that before!

[geardaddy]

14. Win!

[lunatica]

15. Hahahahaha!

Ignorance is bliss until you’re no longer ignorant!

[lapfog_1]

4. often depicted as longer sharp fang teeth... and long pointed tongue

the teeth leaving two puncture marks on the victim because "I vant to suck your blood" (Transylvanian accent included).

which maybe gives them the aspect of "snake like", hence the hissing?

Of course, there was a real Count Vlad Tepish Dracul (Dragon), who had a reputation of driving a spike through the bodies (from buttocks to mouth) and leaving them spiked like that in front of his castle. But not for drinking their blood.

https://en.wikipedia.org/wiki/Vlad_the_Impaler

[procon]

6. Giggling would spoil their image. nt

[Thomas Hurt]

7. They are part cat?

[LunaSea]

8. Might be part possum...

Nocturnal, hissing, hanging out upside down.

[csziggy]

9. Vampire possums?

Now there's an image!

[peekaloo]

10. Ill fitted fangs

not a lot of dentists work at night

[Donkees]

11. A vampire *bat* ''emits a strange hissing vocalization and a fine spray of musky-smelling liquid''

Diaemus possesses a unique feature among the three vampire bats, a pair of cup-shaped oral glands that project forward when the bat is agitated or during displays of dominance. The glands emit a fine spray of musky-smelling liquid. Diaemus simultaneously emits a strange hissing vocalization and a fine spray of musky-smelling liquid from the oral glands.

http://www.naturalhistorymag.com/features/31700/the-curious-bloody-lives-of-vampire-bats?page=3

[lastlib]

12. For the same reason that reptilian monsters....

(which have no vocal chords) growl before they attack.

It's a sound effect the moviemaker uses simply to make them scary.