Behavior, instincs, conditional behavior and so on.

I got a somewhat intense phobia of spiders. I find them both scary and disgusting yet somewhat interesting from mechanical point of view. (My fav Japanese artist Masamune Shirow uses spiders in his designs) I scream like a little girl if a spider is on me. To combat that fear I have been catching the spiders who walk on the walls of my room and watching them. I have been doing this for 2 years now every summer. I would put them inside a plastic cap for DVD folder and let them live there for as long as the can last. Some do last a while, one lasted for 3 months untill it feed it to a prying mantis I had also caught. But this is not really important. What is interesting is all this observations have taught me interesting facts about sociology psychological behavior or animals. By their nature, spiders and solitary predators. They are also cannibals, meaning they will eat one another if the possibility arises. Therefore, spiders tend to run away from one another and don't stand close to each other if possible.
Yet this behavior is drastically altered when I catch and put two spiders together inside one plastic spindle. Surprise surprise, spiders do not attack one another if they are equal size, and they can even stand close to each other. Strange indeed. So spiders (rather lowly animals on the evolutionary scale) modify their behavior when they are in different conditions. Same as pretty much every other animal in existence, including primates, mammals and man. This shows animals will behave in a different manner depending on the conditions they are placed in; even their instincts are altered.