Here's a pretty terrifying fact: the rate of lethal violence among humans is 7 times higher than among other mammals. Of more than 1000 species studied, humans were the ones most predisposed to violence—not only to other species (prey/food), but to each other. Humans are the only species to not only kill each other, but to constantly innovate and create new ways to do so. One psychologist published this in 2016: "Our violence operates far outside the bounds of any other species. Human beings kill anything. Slaughter is a defining behavior of our species. We kill all other creatures, and we kill our own. Read today’s paper. Read yesterday’s, or read tomorrow’s. The enormous industry of print and broadcast journalism serves predominantly to document our killing. Violence exists in the animal world, of course, but on a far different scale. " "Carnivores kill for food; we kill our family members, our children, our parents, our spouses, our brothers and sisters, our cousins and in-laws. We kill strangers. We kill people who are different from us, in appearance, beliefs, race, and social status. We kill ourselves in suicide. We kill for advantage and for revenge, we kill for entertainment: the Roman Coliseum, drive-by shootings, bullfights, hunting and fishing, animal roadkill in an instantaneous reflex for sport. We kill friends, rivals, coworkers, and classmates. Children kill children, in school and on the playground. Grandparents, parents, fathers, mothers--all kill and all of them are the targets of killing…" (Source: R. Douglas Fields, Why We Snap, p. 286, 2016.) Pretty scary, isn't it? So what's causing it? Why are humans so much more violent than other creatures, even predators? Territoriality – Primates are among the most territorial mammals on the planet, and humans are no exceptions. We have an innate need to protect "our land". Why else do you think countries, nationalities, and territories exist in the first place? We humans have a need to "drawn a line in the sand" to mark our territory. When someone else crosses that line, violence is our instinctive reaction. Conscious Awareness – Our intelligence and consciousness is actually one of the primary contributors to our violent tendencies. We can think beyond our basic survival needs, but that consciousness leads to violence for a broad number of reasons (personal offense, territorial disputes, entertainment, etc.). Tight Living Environment – Too many people living close together is a breeding ground for violence. The territorial nature of humans increases the chance of violence should someone "cross that line" of our property. The fact that we're packed so tightly together means there's less space for us to inhabit and a greater risk someone will cross that line. Easy Access to Weapons – Bears only have their teeth and claws, elephants only have their tusks and trunks. Humans have access to THOUSANDS of weapons (all of which we created thanks to our conscious awareness) which make it easier than ever to kill. Freedom – Hard to believe this is true, but it absolutely is. State-run societies intended to suppress violence tend to lead to lower crime rates, but the "freedom" common in modern governments places emphasis on personal choice/decision-making. Given humans' tendency toward violence, it's very likely the freedoms are a contributing factor in the higher violence rates. These are the primary factors that have led to higher incidences of violence among human, but there are HUNDREDS of tiny things that contribute as well.