If you look at ferret eyes in bright sunshine you can see the pupils close
down to narrow horizontal oval shapes (I wouldn't compare it to footballs,
as I think of footballs as round).  Most irises I've seen have been clearly
brown.  Very dark, but still brown.  What I wonder about is if the ferrets
who have eyes which reflect green from some angles, and red from some, has a
structural difference which also influences how they see?
 
Apart from looking at things close up (but not extremely close up, for that
they seem to prefer the mouth as primary investigative organ, and they
cannot see what they're about to put in their mouths) they also seem adapted
to keep on the lookout for threatening birds.  Not that mine have ever shown
any tendency to distinguish a dove from a harrier from a flapping flag...
 
What's interesting is that they definitely do use their eyesight for
navigation, but sort of imperfectly: They seem incapable of telling the
difference between our house and any other similar ones close by which are
oriented the same way, with houses around places in the same pattern.  This
is weird because we don't have the same shape and size of hedges and trees
just outside our houses -- and more importantly; Neither them nor I have
ever visited the other houses (except for one I looked over a year before I
moved here) so lack of "correct" smells from ourselves don't override the
visual input.
 
--
 Urban Fredriksson   [log in to unmask]   http://www.canit.se/%7Egriffon/
 http://www.alfaskop.net/%7Egriffon/ferrets/
[Posted in FML issue 2167]