Subject: eyesight, whales

Michael Williamson (pita@whale.simmons.edu)
Fri, 17 Jan 1997 15:28:57 -0500 (EST)

Date: Fri, 17 Jan 1997 13:24:15 -0500
From: Patrick Miller <omalley@cetacea.whoi.edu>
To: ask@whale.simmons.edu, pita@whale.simmons.edu, signman@spectra.net
Subject: ASk Questions


Dear Jordan,

>>  I know whales have poor eyesight but can they see in color?


   Actually, dolphins (including killer whales, which are the largest
member of the dolphin family) see very well underwater, and can also
see well in air.  Some of the early work studying killer whale vision
was done by Paul Spong at the Vancouver Aquarium - and he showed that
they see about as well as cats.

   Dolphins also have the ability to move their eyes independently,
which means, for example, that they can look at something in front of
them with one eye, and something else to the side with the other! It
seems, however, that dolphins are unable to see well in color. Except
in shallow water, color underwater is limited mostly to
bluish-green. (This has to do with how light is filtered through
water.) Color vision underwater, then, may not be all that important
to dolphins, compared to an ability to see changes in light and dark,
shading and contrast. The different shading patterns on many species
of dolphin may be important visual cues for individuals to pick out
each other's position and orientation.

>> Do you think Keiko will ever be ready enough to go back to the wild
>> after 20 years?

   While there have been some successful reintroductions of captive
dolphins to the wild, the reintroduction of Keiko would the first
killer whale to be reintroduced to the wild after a long captive stay.
Some killer whales were temporarily held captive and then released,
but that was for days, not years.

   Personally, I think it would be great if Keiko could be
successfully reintroduced to the wild, but it will be very difficult
for Keiko to make the transition.  The wild is a very difficult place,
food is rich in some times of the year, but can be very scarce at
other times of the year.  Even if Keiko can be taught to eat live fish
again, I think it very likely that she will be less efficient than
other killer whales and may not survive as a result.

   Some people think that if Keiko's family can be found in the wild
that they would help her to survive.  While this is a possibility, it
will be very difficult to find her family (somewhere off Iceland), and
it is unknown if her family would really accept her back.  Even if
they did receive her back to their group, it seems likely that she
would be the weak-link in the group and may decrease their ability to
survive as a group, which would not be a very positive result either.

    So, there are a lot of things to consider for reintroduction and
there are no easy answers, mostly because our scientific experience in
this area is lacking.

				yours in whale research,

					-Patrick