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| Colobus Monkeys photo credit: Daryona |
Many of us have the luxury of waking to the dulcet
tones of an alarm clock. Others may be woken by young kids who seem to have
boundless energy, an insatiable appetite, or both. Even our cat or dog will
take it upon itself to remind you of your duties. But why it’s necessary for
some species to get up before the sun just to annoy their neighbors seems to me
to be a very strange habit.
Birds do this regularly with their dawn chorus,
which would be better named pre-dawn chorus. Outside my window in the summer,
the swallows push and shove, flutter and squawk, and make a terrific noise
until the sun comes up. Then they shut up and go back to sleep leaving the rest
of us with dark thoughts for the day.
It’s not only birds that make a joint effort at a
pre-dawn racket, some primates do it too. I recall hearing gibbons calling to
each other at the crack of dawn, but these sound more romantic than a racket.
Howler monkeys get together at the edge of their territory and hurl abuse at
their neighbors for a while in the New World while Colobus monkeys keep up
tradition in the Old World and get it off their chests for a couple of hours
before the sun rises.
This friendly gesture by a band of Colobus guereza
was investigated by Schel and Zuberbühler and reported in the
online edition of J. Behavioral Ecology and Sociobiology (1,2). Not just
satisfied with just listening to the loud staccato throat clearing sound by
their chosen band, they decided to join in.
Maybe
it was to get their own back on being woken early, but what they did was to
play recordings of the Colobus chorus around the forest before their band had
woken up and got their act together.
The
results were interesting. Playing snatches before the Colobus guys were up
didn’t get much response. They had to give it more than half a minute when the
band were getting ready to tune up before they could elicit a response.
Although their study showed that they could distinguish individual voices in
the cacophony, they concluded that the chorus was democratic and no one seemed
to be responding to any particular individual.
Seems
that there isn’t too much competition for a top solo spot, but the effort is in
shouting down the neighbors. I guess that, as is invariably the case, an
acoustic assault is preferred to a physical one. One is left to wonder why, if
this is a regular occurrence at 2 hours before dawn, there are any neighbors
left.
