This size is reflected in the range of sound frequencies the ferret can
hear.  Comparative auditory frequency ranges for animals have been well
documented (Fay 1988, Fay and Popper 1994), including those for the
ferret.  These studies suggest the approximate range of frequencies heard
by the ferret extend from 16 to 44,000 Hz.  To give these numbers some
real-world significance, human auditory frequency range extends from 64
to 23,000 Hz (some individuals can hear lower or higher--the value
represents a human average), dogs hear from 67 to 45,000 Hz, and cats
hear from 45 to 64,000 Hz [NOTE: some studies give different numbers
because of the way the tests are done.  For example, humans can hear down
to 30 Hz if the sound is extremely loud]  Ferrets can hear down to 16 Hz,
an EXTREMELY low frequency sound; being able to hear such low-frequency
sounds would be a great advantage to an animal specializing in hunting
underground (the only other (tested) animal that reliably hears such low
sounds are elephants, recently discovered to communicate using subaudible
sounds).  44,000 Hz is well above the ability of humans to hear sound,
being in the realm of dog whistles.  It is clear the range of sounds,
both subaudible and ultrasound, heard by ferrets is well beyond those
of humans.
 
This has two important implications.  First, it means ferrets can
perceive sounds beyond the range of human hearing, suggesting they are
more sensitive to noise pollution.  Ferret owners should be aware of
this, and take steps to reduce noise levels that may have an impact on
ferrets.  Second, it means ferrets are well attuned to acoustics, which
can be used in an enrichment program.
 
1. Whistle While You Dook: Start collecting whistles of various types.
Assign a specific "task' to each whistle.  For example, blow the slide
whistle when opening the cage for playtime, the flute when giving baby
chicken, the referee whistle when giving Nutrical, etc.  It will not
take long for the ferrets to learn which whistles mean what treat, and
will respond accordingly, depending on their personal preferences.
 
2. Speaker Up: Place a small cassette or CD player in a small box, and
load up a CD or tape of bird songs or natural sounds.  Turn on the
machine to play the tape/CD at a moderate sound level and seal the box,
then placed the sealed box inside a larger box, perhaps partially filled
with paper balls.
 
3. For Whom the Bell Rolls: Fill toilet paper or paper towel tubes with
a small handful of jingle bells (use the 1 inch size in case the tube is
opened).  Seal both ends with duct tape and just toss them on the floor.
Heighten the sensory experience by soaking the tube in something smelly
beforehand.
 
4. Cellophane Boxing: Fill a small box with crinkly cellophane, close
and seal the top, and cut a single access hole.  Just try keeping the
ferrets out of the box.
 
5. Sandy Polecat: Seal one end of a paper towel tube with duct tape,
then pour a small handful of sand or gravel (or jingle bells) into the
tube.  Seal the opposite end with duct tape.  Find the exact center of
the roll, and using an ice pick, punch a hole through the tube.  Using a
short piece of wire as a "sewing needle," thread a couple of feet of cord
through the tube.  Place the sand-filled tube inside a tall box, punch a
few holes near the top on opposite sides, and tie the sand tube so that
it will freely rotate, suspended by the cord.  Smear something smelly on
the cardboard tube to increase interest, and let the ferrets investigate.
 
Bob C
[Posted in FML issue 4213]