Subject: colour perception in whales
> Do Whales see in black and white or in color?
Dear Merryl ( and 2nd graders):
The order of whales (Cetacea) contains more than 80
species. This diversity includes animals that live and
forage near the surface, and others that dive
regularly into the dark depths. The requirements for
sight differ in these extremely different environs.
It appears that whales and dolphins that keep near the
surface have the most accute eyesight. while the deep
divers rely less on eyesight.
Eye sight relies on receptors which are modified nerve
cells called rods and cones. Seeing in dim light
relies mainly on the rods. Cetaceans have a greater
number of rods as well as larger rods than those of
terrestrial mammals. Deeper diving mysticetes (baleen
whales) have the longest rods of all.
Cones are the receptors associated most with colour
perception. The retina of most whales do have cones.
Therefore we can say that most whales can perceive
colour. However, colour becomes meaningless as one
dives more than a few meters below the surface where
most of the light at the red end of the spectrum has
been absorbed by the water above.
The reason I say "most" can perceive colour is that
some species of cetaceans have very small, much less
functional eyes. For these few species, seeing dark
and light is about all they can hope for.
Alaska Whale Foundation
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