It is not surprising that animals communicate through sound, but Elizabeth von Muggenthaler has found something very special about how giraffes communicate with each other. For many years, animal behaviorists believed giraffes to be the ‘silent parties’ of the animal world. However, advances in technology have allowed scientists to detect sound frequencies outside of human senses. As it turns out, giraffes use low frequency sounds to communicate, much like whales and elephants.
These low-frequency sounds are called ‘infrasound’ and they have an amazing property: to traverse across many miles. In contrast, high-frequency sounds travel a much shorter distance across open air and ground. Studying this type of sound in the field is extremely difficult because background noises can very easily interfere with the recording equipment. Therefore, the bulk of study on giraffe communication has been completed in a zoo or semi-domestic setting. Even in a domestic setting, all data must come from analyzing software – a scientist must depend on a computer, and not on their own observations, to collect data. Muggenthaler is the pioneer in these zoo studies.
As the giraffes are making the low-frequency sounds they tend to stretch out their necks or throw their heads. Muggenthaler seems to think that these behaviors change the way the air moves through the giraffe’s neck. The way a giraffe’s ear is shaped (like a parabola) is perfect for picking up and tuning in on these specialized noises.
To Muggenthaler, the fact that giraffes are not silent has always been obvious. She states, “…here is an animal that is very social, they hide in forests [making visual communication difficult], and they hide their young during the day while foraging. They are hunted by other animals. But they were considered mute. Right there is your clue — there are no animals [that have such behaviors] that are mute. They wouldn’t survive if they couldn’t communicate. “
Communication, even for these giants, is essential for survival.
Read the full article here: http://www.pbs.org/wnet/nature/episodes/tall-blondes/silent-sentinels/2256/
EDIT:
Giraffes use low frequency sounds like elephants and whales. However, elephants and whales both also use sounds that humans can perceive in addition to the infrasound. All three animals need to communicate over long, open distances, and low frequency sounds are best for transmission. Interestingly enough, some behaviorists have suggested the reason many animals fled the asian shoreline before the 2004 tsunami is because of infrasound produced by the incoming tidal waves, so obviously many animals are able to detect low frequency sound, but just not as many use it as their main communication device.
I have always wondered what noises giraffes make. It's so interesting that it is in the form of low-frequency noises. The reasons behind this form of communication make so much sense. It is weird that it was not figured out before now. I wonder if there are any other animals previously considered mute that communicate in a way that humans cannot hear.
ReplyDelete-Tricia Carlson
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ReplyDeleteIt is interesting that we have finally figured out how giraffes communicate. It didn't seem possible that there was no communication going on within the species because survival of the species would be unlikely. What recording/software was used to detect and analyze these low frequency sounds? Why do you think calls that could travel long distances were used in particular for this species? Do you think this low frequency sounds can be heard by most species- just not us?
ReplyDeletePosted by Tiffany Mallet