September 21 – Humming along

Today’s factismal: Giraffes make a humming sound at night.

If you ask a kindergartner what a cow says, she can tell you. If you ask what a lion or tiger or even a fox says, you will probably get an answer. But if you ask what a giraffe says, the only answer you are likely to get is silence (or “give me a cookie”). And it turns out that kindergartners aren’t the only folks who don’t know what sound a giraffe makes; until recently, scientists didn’t know, either.

A giraffe nibbling on acacia trees (My camera)

A giraffe nibbling on acacia trees
(My camera)

Even though giraffes have a larynx like a human, people never heard them make a noise. As a result, many thought that the same neck that allowed giraffes to nibble leaves from the top of acacia trees also made it too difficult to push air through the larynx and make noise. But some scientists thought that if that were the case then the larynx should have atrophied and been lost long ago, like the panda’s thumb; since it hadn’t, the giraffe must make some noise. So they placed listening devices around giraffes in zoos and listened to them for three years. All told, they amassed some 40 days worth of recordings. And when they filtered out all of the other noises, the scientists discovered an amazing thing: giraffes hum at night!

Giraffes stand tall. Really, really tall. (My camera)

Giraffes stand tall. Really, really tall.
(My camera)

Right now, the scientists aren’t sure exactly why the giraffes hum but they think that it may be a way of keeping the troop together in darkness. Though giraffes have very sharp eyes, those don’t do much good when the Sun goes down. Like a troop of soldiers singing a Jodie to keep everyone in step, giraffes can keep track of who is where by listening for the humming of other giraffes. And it gets better; it is also possible that the giraffes use infrasound (very low sounds) similar to those made by elephants and parasaurolophus to communicate.

And right now, communication is vital. There are only about 80,000 giraffes left in the wild, down from nearly 200,000 just a few years ago. In order to protect the remaining giraffes, scientists need to know where they are and what they are doing – and that’s where you come in! If you have pictures of giraffes, especially giraffes in the wild, then why not load them over at Giraffe Spotter? And even if you don’t have pictures of giraffes, why not head over to their website so you can dubberneck at the images that other folks have put online?
http://giraffespotter.org/

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