Trout Senses

Trout, as with most animals, are very in tune to their surroundings. They locate, inspect, and eat natural foods using their senses of sight, hearing, smell, and taste/touch. They use a highly developed set of senses to locate foods and to avoid or escape their predators.


Sight
Trout possess a very keen sense of sight although they have no need to see more than 20 or 30 feet away because of water clarity. Trout see through what scientists have called the “trout’s window”. This is a cone shaped view extending up from the trout’s eye at an increasing diameter. Without going into details, this is why trout see better at greater depths. They also have good color vision which is why fishing the same fly in two different colors can produce drastically different results. Trout possess excellent night vision as well. I’ve never personally done any night fishing as I don’t enjoy the extra challenges it involves but have talked to those who have, many with great success. Sight is arguably the most important sense a trout uses when deciding whether or not to take you’re offering. Because of these things it is important for the angler to make sure he presents the fly upstream from the trout so the fly doesn’t suddenly appear in its window and give it a chance to be spooked.


Hearing
Trout have highly developed dual hearing systems. First, the ears in their heads are used to detect the movement of nearby objects. These ears allow the trout to hear sound frequencies well outside the human hearing range. This hearing receptor of the trout is what allows the fish to find food even in very murky water.
Fish also have a lateral-line system on each side of their bodies that picks up frequency vibrations. This lateral line, which runs from behind the head to the base of the tail, is a series of tiny drum-like membranes with nerve endings that run back to the spinal cord.
Some things to note about a trout’s hearing are: 1) Trout cannot hear human voices as we speak at a range outside of their hearing frequency so it’s ok to have the stream-side conversation. 2) Trout are very aware of their surroundings so it is important to wade slowly and quietly so as not to spook them and stay as far back from the target area as possible.


Smell
Amazingly, trout have a highly developed sense of smell that is much better than that of humans and supposedly even surpasses that of other animals. For this reason it is important that you don’t introduce any foreign smells into the water. When heading out to the stream leave the smelly colognes and deodorants in the medicine cabinet until after you’re finished fishing. Also, take care to purchase the newer fly floatants and line cleaners that “mask” the chemical smell. Be careful with the insect repellents as well as these smells are not masked and are quite foreign to trout.


Taste/Touch
On the surfaces of their bodies, fins, and mouths, fish have sensors that can taste and feel their foods. These are considered secondary senses which are used after the potential food is located or captured. A trout might locate your fly and rub its body across it or bite it to determine if it is real food or fake. This is demonstrated when it appears that the trout has missed the fly when, in reality, it has touched and tasted it and in an instant rejected it because it did not feel or taste right. This is why you must react to a strike quickly before the fish can recognize your fly as a fake and reject it.