Song of the Siamang

I've always wondered - who was it who decided that monkeys say "Ooo, ooo, aah, aah?"

I've never heard a monkey say anything like that.  I have heard about five hundred thousand visitors say it to the monkeys, hoping that it'll elicit some sort of response.

It actually shocks me how quiet primates tend to be.  When you consider how loud humans are, monkeys, apes, and lemurs are - on the whole - fairly silent animals.  When they do make sounds, they are often relatively soft and melodious.  The twitter of tamarins and marmosets is often likened to the calls of birds; visitors who walk by our tamarin exhibit in a hurry might hear them but not see them and assume that there are just birds in there.  Spider monkeys make a call like the soft whinnying of a horse.  The call of a lemur reminds me of the distant voice of a seagull. 

Which isn't to say that primates can't be loud as all heck when the need arises.  Let a stray dog sneak into our zoo and run past the monkeys.  You'll hear some screaming that will be haunting your nightmares years from now.  Our ruffed lemurs will sometimes holler for no apparent reason - I've rushed over, convinced that they must be killing each other, only to see them casually draped over branches, looking at me curiously as I race up to the fence, wondering what all the fuss is about.  And of course chimps can make a din when the mood strikes them.

It makes sense that primates have such great sets of pipes for when the need arises.  They are (mostly) social, and therefore need to stay in touch.  Most species live in the forests, where it might be hard to see one another because of leaves and branches, so vocalization works well for transmitting messages... such as territoriality.

The loudest of the primates are the howler monkeys of the Neotropics and the gibbons of Southeast Asia.  The call of the black howler monkey can be heard two miles away, three if there is nothing blocking it.  The call of the siamang, inflated by its throat pouch, can be heard two miles away as well - not quite as loud, but, to my ear, a bit more melodious.  Not that you'd want to hear it outside your bedroom every dawn... as was my experience when I lived on grounds at one zoo.

No matter how chatty primates at the zoo may be, it's best to respect them and their homes by not starting a din, nor contributing to one that is in progress.  Howler monkeys and gibbons don't whoop for fun - they do it to defend their territories.  You calling at them is, in reality, a challenge to their sovereignty, and it can be exhausting, intimidating for them to feel like they have to re-claim their territory every time an elementary school class comes up to the rails. 

If you are lucky enough to hear them vocalizing, sit back and enjoy it... and then be glad that it doesn't serve as your alarm clock every morning.