A Tail that Tells it All

Researches have argued that humans are the only animals who show signs of brain assymetry, referring to the different behavioral functions assosiated with the left and right brain hemispheres. But in the more recent years, studies have shown that "simpler" species (such as animals who lack complex behaviors such as speech and comprehending language) have been displaying behaviors that lead scientists to lean more towards the idea that many animals have brain assymetry.

In humans, the left side of the brain corresponds with behaviors such as approach and energy enrichment and is associated with emotions like attatchment, love, and safety. The right hemisphere specializes with behaviors like fleeing and energy expenditure and assosiated with emotions such as fear and depression.

Since the right hemisphere controls the left side of the body and visa versa, animals will preferably

"seek food with their right eye (left brain/nourishment) and watch for predators with their left eye (right brain/danger)."

"Male chameleons show more aggression, reflected as changes in body color, when they look at another chameleon with their left eye. A toad is more likely to jump away when a predator is introduced to its left visual field (right brain/fear). The same toad prefers to flick its tongue to the right side when lashing out at a cricket (left brain/ nourishment)."

These are are more specific examples of the brain symmetry in animals. Even your pet dog will display this phenomenon as well.

Tail wagging in dogs is a trait that tells more than you think. Many assume that a wagging tails means the dog is happy, but there is more to it.

Dr. Vallortigara of the University of Triesty in Italy performed an experiment in which him and his collegues placed 30 pet dogs in a cage and throughout the time span of 25 days, he introduced them to 4 kinds of stimuli with 90 second resting periods intermittenly: their owner, an unfamiliar human, a cat, and an unfamiliar alpha dog.

"When the dogs saw their owners, their tails all wagged vigorously with a bias to the right side of their bodies,"

Dr. Vallortigara said.

"Their tails wagged moderately, again more to the right, when faced with an unfamiliar human. Looking at the cat, the dogs’ tails again wagged more to the right but in a lower amplitude."

"When the dogs looked at an aggressive, unfamiliar dog — a large Belgian shepherd Malinois — their tails all wagged with a bias to the left side of their bodies."

All the results lead to the verification of their original hypothesis:

"The muscles on either side of the tail apparently reflect emotions like fear and love registering in the brain."

http://www.nytimes.com/2007/04/24/science/24wag.html?pagewanted=1&_r=2
http://faculty.washington.edu/chudler/split.html

Posted By: Natalie Nicholson (11)