Jumping Spiders' Unique Vision Revealed [LiveScience 2012-01-26]
[Photo] Adanson's House Jumper (Hasarius adansoni). The jumping
spider has two sets of eyes. Its two lateral eyes help the
spider see motion, whereas its principal eyes gauge depth.
CREDIT: Science/AAAS Jumping spiders, which hunt by pouncing on
their prey, gauge distances to their unsuspecting meals in a way
that appears to be unique in the animal kingdom, a new study
finds. The superability boils down to seeing green, the
researchers found. There are several different visual systems
that organisms use to accurately and reliably judge distance and
depth. Humans, for example, have binocular stereovision. Because
our eyes are spaced apart, they receive visual information from
different angles, which our brains use to automatically
triangulate distances. Other animals, such as insects, adjust
the focal length of the lenses in their eyes, or move their
heads side to side to create an effect called motion parallax —
nearer objects will move across t