"Aggressive behavior" refers to actions that are forceful, hostile, or combative towards others, either physically or verbally. It involves behaving in a way that may harm or intimidate others intentionally. Full definition
A common underlying cause of aggressive behavior in children under the age of ten is related to fear and an inability to self - regulate. (positiveparentingconnection.net)
One of the most characteristic types of aggressive behavior in dogs is biting — something we dread whether we own a dog or not. (animals.howstuffworks.com)
One study found higher levels of testosterone correlated with aggressive behavior in 12 - and 13 - year - old boys, but not in 15 - and 16 - year - old boys. (discovermagazine.com)