Elephant Listening Project
Although downward pressure on the survival prospects of forest elephants continues – indeed is likely increasing – there are a few positive signs to keep us striving for a better future.
Toward Being Positive
As a start, we can be thankful that there has been no more poaching in Dzanga Bai. Andrea’s team of Bayaka are keeping a presence at the clearing and anti-poaching patrols are apparently continuing. Next, the plight of elephants is getting media attention on a scale not seen since just before the 1989 CITES ‘ban’ on trade in ivory, and this can’t but help. The international community has launched a 3-year “Commitment to Action” that will bring together conservation organizations, governments, and money to “Stop the killing, Stop the trafficking, and Stop the demand”. If a useful amount of this effort, and especially funds, manage to trickle down to actually doing something effective in the forests of Central Africa – good. Unfortunately, in the past the lion’s share of such funds have been eaten by working groups, attendees to talk-a-thons at expensive venues, and corrupt organizations. Less talk by the ‘experts’ and more help for the guys on the ground who know what is happening would be refreshing. But let's turn to some exciting new discoveries about elephant biology.
New research has demonstrated that elephants can actually speak with two voices! They can either talk through their mouths or from the end of their trunks –the resulting rumbles are different and might be used for different types of communication. How cool is that?
Although elephants produce sounds in much the same way as we do, using their vocal folds to generate the source (fundamental) frequency and then modifying the sound’s structure by ‘filtering’ it with the shape of their mouth cavity and the nasal passages, that nasal passage is something else when it comes to an elephant! The trunk gives elephants an extra six feet of ‘filter’ to use if they want to. The ‘filter’ lets an animal concentrate sound energy in different parts of the call structure and the longer the filter, the lower in frequency (tone) those areas of concentration can be (published article). Because of this relationship, we already knew that elephants used their trunks to shape their calls. What we didn’t know was that sometimes they actually send those sounds out through the end of the nose instead of the mouth.
This video shows the 'nasal' rumble.
By using a special dense array of microphones that let them localize where the sound energy was coming from, scientists actually filmed these two types of rumbles. Energy in the 'nasal' rumble was concentrated at lower frequencies and the scientists speculate that perhaps this type of rumble is particularly important for the longest distance communication.
This video shows the 'mouth' rumble.
All of us at ELP hope your year is ending as a positive one and that elephants get a better shake from our species in the coming year than they had this year.
Peter H. Wrege,
Director, Elephant Listening Project.