Page 99 - Zoo Animal Learning and Training

Box A1 Animal Vision 71

VetBooks.ir These abilities allow them to make use of sig- frames that the eyes send to it. The rate at
which these are generated influences an ani-
nals that we cannot see. It is important to
remember that whilst birds, insects, and
erate and process information at 60 images
some mammals such as rodents (Jacobs et al. mal’s visual perception of time. Humans gen-
1991), reindeer (Rangifer tarandus) (Hogg per second, whereas smaller species with
et al. 2011), and a phyllostomid flower bat higher metabolic rates typically process
(Glossophaga soricina) (Winter et al. 2003), images at a higher frequency (Healy et al.
can detect ultraviolet light, they do not see 2013). To them the world will appear as if in
solely in ultraviolet. The images that they see slow motion, whilst larger animals which pro-
will depend on how their brain combines the cess images at a lower rate will experience the
information from the ultraviolet portion of world in a manner akin to a time‐lapse
the spectrum with that from the receptors film – for them perceiving slow moving
tuned to what we refer to as the visible spec- objects as moving may be difficult. The
trum. The same will be true of the butterflies refresh rate of televisions and monitor screens
and fish that can perceive near infrared (Land is set to just above the human threshold for
and Nilsson 2012). seeing the individual images, and thus we
Animals also differ in the way that they per- perceive motion rather than a flickering series
ceive movement. Like colour, movement is of images. However species with higher rates
such a key aspect of our own visual world it is of visual processing, such as dogs and small
similarly hard to comprehend it is not always animals, would see a flickering screen. This is
seen in the same way by other species. Motion important to remember if using a monitor
perception is generated by the brain com- screen as a stimulus, either for enrichment or
paring the series of successive snapshots or research, with other species.

References

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what they don’t: luminance, contrast, and (1991). Retinal receptors in rodents
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