To answer this long standing question one must first understand what is nature and what is nurture. Nature is genetics, the traits animals inherit from their families or bloodlines. Nurture is the outside world, the environment one is put in. The question of which is more important nature or nurture is a debate that has been going on since the days of Aristotle (384 -322 B.C.). Aristotle wrote the first known book of psychology. (Shields, 2000) Essentially, nature is the foundation to which the animal traits are based upon. Some of the traits become less notable dependent upon the environment the animal is placed in Nurture.
The most easily identifiable examples of nature versus nurture would be dogs. In observing dogs of different breeds one can see behaviors that can be identified as being specific to the breed. Even in mixed breed dogs the dominant genetic behaviors can be readily identifiable to a specific breed. Some dogs are very laid back, kids can pull on their ears and the dog just sighs and goes back to sleep. This could be a genetic predisposition such as observed in Golden Retrievers. However, if that same Golden Retriever was beaten or traumatized in some way (Nurture) the dog may scurry away or even bite the child. Another example is the Border collie; the Border collie’s natural genetic instinct to “herd” can be uncontrollable for them. Even in dogs that are only part Border collie often display this trait. The Border collie can be taught several tricks involving moving objects such as Frisbees or balls. If none of these items are available they will herd children and most dangerously cars. Border collies through nurturing (environment) can also become very docile this is not in their genetic nature. Dogs are generally happier and healthier doing what is natural to them.
One can look back throughout the history of a breed and sometimes be able to look at a dog currently and still identify the traits described historically. There are some breeds that do not do well with children and some are naturally aggressive, or cautious. If the dog is in a good home its entire life and is healthy any aggressive traits are most likely genetic. Lhasa Apsos are genetically weary of strangers. Jack Russell Terriers can be naturally aggressive towards other dogs. St. Bernard and Rottweiler’s will let an intruder in but will not let them out; they will hold an intruder in a corner for hours. These are all historically natural genetic traits.
Staged dog fights are a result of conditioning (human influence not nature). If you beat a dog it will become aggressive or standoffish as a result of fear. As would any human being. The dog will not be mentally healthy if nurturing is not appropriate and outside factors are less than desirable. As would a human, this can be seen in feral children for more information visit http://www.feralchildren.com/en/index.php the site is hard to view but it shows without a doubt what the effects of nature versus nurture can be. With these children the result is the same as would be seen in the animal kingdom with any animal (mammals). Reptiles are a little different in regards to nature versus nurture, though one can teach a larger reptile such as bearded dragons to behave similarly to a dog. Some will even greet you at the door after a long day. Smaller reptiles tend to just lose their fear of humans with nurturing. No fluffy the Leopard Gecko doesn’t sit happily on your should because of his genetics. So nature being a stronger influence than nurturing truly depends on the breed and type of animal one is dealing with, animals of higher intelligence will show results for nurturing but one will still see nature or genetic traits show through unless the damage from environment are completely devastating. One can sometimes use healthy nurturing to bring back out the genetic traits in any animal, because after all genetics are hardwired in every living thing.
Reference:
Shields, C. (2000). Aristotle’s Psychology. Stanford Encyclopedia of Psychology, Retrieved 7/3/2009, from http://plato.stanford.edu/entries/aristotle-psychology