It is important to understand how we see, because we don’t see like you humans.
Sight however is not our primary sense. We use smell as our Primary sense (which we will talk about tomorrow). We experience our environment in a different way than you humans. Knowing how we use our senses will better help you understand how some training techniques will work better with us than other ways. Therefore getting better results and being a better team together! Which is something we want to achieve as well, BUT we need to understand one another first!
Understanding the way we see will explain to you why a dog seems to be ignoring the handlers direction when they may not actually be!
The Canine eye resembles the human eye but have their differences.
The Sclera surrounds and protects the eyeball, unites the cornea in the front which is tough and transparent. When viewed straight on it is nearly invisible. Behind the cornea are the iris and pupil.
The iris, ciliary body an choroid comprise of the urea layer.
The iris is a muscle under control of the autonomic nervous system. The iris responds to the level of light by opening and closing to regulate the amount of light entering the eye. The iris is what you see as the colored portion of the eye.
*Dogs usually have brown, hazel/ amber, or blue eyes.
The ciliary body performs several functions as well as suspending the iris. It contains blood vessels and muscles that alter the focus of the lens. It also attaches to the sclera to hold everything in place.
The Retina is complex and prone to susceptible to injury. The eyeball lies protected in the socket bone only open in the front. Obviously those dog with bulging eyes are more susceptible to injury. The Retina has two layers- the outer pigmented layer and the inner nerve layer. The inner layer receives the light impulses arriving at the eye and consists of rods and cones. Cones are responsible for detecting color. Dogs do have 10% cone receptors to detect color, as opposed to that of the 100% people have. Since they have a high percentage of rods they are more light sensitive which provides them the ability to see in low light situations.
The Abilities of Canine Vision
Dogs cannot make out the difference between orange from green from red. But they can make out the difference between the grey scale and to a higher degree than humans. The amount of light a dog needs for vision is four times lower than that of a human. (An animal in the wild hunts in the low light conditions, so this comes in handy.)
Field of view
The general field of view of a dog is generally between 240 and 250 degrees compared to the 180 degrees for a human.
Dogs are able to see more of what’s going on around them, see diagram below.
Dogs also lack the accommodation ability meaning they can’t accommodate at upclose distances, we stop focusing from 50-33 centimeters away. We shift to using scent, taste, or touch for close objects. For example: a person with 20/20 vision sees at 75 ft away, whereas a dog wouldn’t be able to see until it was only about 20 feet away.
However dogs trade off visual acuity for better low- light vision and a greater sensitivity to motion. (i.e. they are our motion detectors at night!) This is due to the fact they have a greater number of rods than cones as well.
What do dogs Rely on…..
Dogs rely on body language for communication. As well as use motion to recognize those they do not know at a distance.
KEEP IN MIND: TV for a us is like watching an old time jerky flickering silent movie whereas it is just fine for people.
Ok, so we learned alot today about our canines vision and ability, which is important to know for a great training session(s), tomorrow we will learn more and go into our canines hearing and ability.
Until tomorrow have a happy and healthy tail waggin’ day.