the low-frequency listener

[Doug Millison]

.... Starting last year, the watcher and the listener teamed up in 
hopes of both exploiting and deciphering elephants' low-frequency 
lexicon - rumbles that are mostly below the range of human hearing 
but that travel for miles in hot equatorial air. Ms. Payne, who is 
63, did the first detailed studies of these "infrasonic" calls in 
1984, after feeling the air throb near a zoo elephant just as it had 
when she stood near a pipe organ while singing in a church choir as a 
teenager. Certain low-frequency calls appear to be used by estrous 
females to attract males and by family groups so they can forage in 
the same direction even though individuals might be separated by 
miles of impassable greenery. .... The Elephant Listening Project, as 
Ms. Payne calls the effort, is partly intended to decode elephant 
language, but also to see if it is possible to estimate the number of 
elephants hiding in the dense jungle and to gauge their behavior by 
eavesdropping on their communications with networks of microphones. 
....  Mr. Gulick once designed missile- tracking radar, but after a 
few trips to Africa a decade ago has since devoted his time to 
devices for tracking elephants. ....

http://www.nytimes.com/2001/01/09/science/09ELEP.html?pagewanted=all