Sat, 19 Mar 2016-06:15pm , PTI
Did you know this?
The vision of small perching birds in the
wild is twice as quick as humans and faster than any vertebrates, according to
a new study.
Researchers from the Swedish University
of Agricultural Sciences, Uppsala University and Stockholm University in Sweden
studied the ability to resolve visual detail in time in three small wild
passerine species - blue tit, collared flycatcher and pied flycatcher.
The ability is the temporal resolution of
eyesight, that is the number of changes per second an animal is capable of
perceiving. It may be compared to spatial resolution (visual acuity), a measure
of the number of details per degree in the field of vision, researchers said.
They trained wild-caught birds to receive
a food reward by distinguishing between a pair of lamps, one flickering and one
shining a constant light.
Temporal resolution was then determined
by increasing the flicker rate to a threshold at which the birds could no
longer tell the lamps apart.
This threshold, known as the CFF
(critical flicker fusion rate), averaged between 129 and 137 hertz (Hz). In the
pied flycatchers it reached as high as 146 Hz, some 50 Hz above the highest
rate encountered for any other vertebrate, researchers said.
For humans, the CFF is usually approximately
60 Hz. For passerines, the world might to be said to be in slow motion compared
with how it looks to us, they said.
No comments:
Post a Comment