<http://www.smallanimalchannel.com/ferrets/ferret-interaction/20-fascinating-facts-about-ferrets.aspx>

On ferrets having both types (short wavelength and long wavelength) of
cones in their eyes, indicating that physiologically there is potential
for seeing a wider spectral range than some had thought:
http://www.ncbi.nlm.nih.gov/pubmed/12699079
http://www.ncbi.nlm.nih.gov/pubmed/11328346
Types and locations matter.

Years ago we had a ferret who would preferentially steal and stash blue
items, at times having stash places with only blue things, indicating
a reason to question previous thought on this matter for at least some
individuals. She taught when she stole...

Yes, I know there were people in the U.S. with pet ferrets before the
1970s; that is when they began to be found in more than rare families.
When we first had ferrets in our family over thirty years ago pet
stores were already selling them but some stores were actually selling
unhealthy biting fur fitch to customers rather than healthier pet stock
ferrets. Some private breeders back then also had unhealthy and very
inbred stock. Back then if a person was not careful it was possible to
get ferrets through either approach who had enough genetically wrong
with them that some lines would USUALLY die below three years of age.
After that early time there wound up being healthier stock usually with
standard markings available -- yes, MF, Colorado Ferret (the original
farm is long defunct), PV, and certainly Wendy Winstead -- actually
increased pet store ferret lifespans which doubled and tripled compared
to way too many of the earlier sources. More recently with so many
fancies introduced, the lifespans of some lines have decreased once
again for other genetic reasons, though it is still quite normal to
have ferrets reach middle seven to middle eight years, sometimes older.

Although I wrote the linked article at the top, below that article you
will find other links including another in the 20 points series that
Wolfy wrote:

<http://www.smallanimalchannel.com/ferrets/ferret-behavior/20-strange-but-common-ferret-behaviors.aspx>

[Posted in FML 8048]