Comparative Sensory Systems

[Ready for Fall 2026]

Modified: 2026-07-29 1:46 AM CDST

• Sensory systems are no1t alike throughout the animal kingdom.
• It is a mistake to assume that our perceptions are similar to the perceptions of other animals.
  • For example, we use blaze orange clothing during deer season to prevent the accidental shooting of hunters.
  • Deer, it turns out, can see blaze orange too, but do not react to it to any degree.
• Another example involves odor.
  • All of us have a different body odor.
  • Dogs can identify people easily by their body odor, whereas humans have a great deal of difficulty in doing so.

  • Plus, humans use deodorants, colognes, and other substances to alter their natural odor
• So, sensory systems in different species evolved to meet the ecological requirements of each species.
  • A good example is the eye.
    • Rats' eyes contain only rod cells, or cells that do not detect color, and work best in low light situations.
    • Pigeons' eyes, on the other hand, contain only cone cells, or cells that detect color, but do not work well in low light situations.
  • Now, think of where rats and pigeons live and when they are active.
    • Rats live in burrows and are active at night.
    • Pigeons fly during the day and roost at night.
    • Rats would not make good subjects for color vision studies, but pigeons would.
    • In fact, you can catch a pigeon in a room, if you wait for it to land and then turn off the lights (you need near total darkness).
    • Then you can sneak up on it and grab it.
• Finally, all sensory systems can be labelled transducers.
  • Transduction is the process of converting a physical force into neural information.
  • All of the sensory systems transduce physical forces, but each in a different way.
  • The rest of this chapter will consist of detailed descriptions of how that each type of transduction occurs.