Some people will talk about 'what separates humans from animals'.
Some people will says it's grammar, but there are monkeys in the rainforest that make calls in different orders to apparently mean different things.
Some say it's lying, but again, the same set of monkeys will make a call at warn of a snake for example just so they can have the best bit of food.
Some say it is our ability to mourn the dead, but herds of elephants stop and mourn when a member of the group dies.
But if you ask me, it's our knowledge of out own mortality. yes animals have a sense of self preservation but they aren't aware that some day they will die. in this case i think the phrase 'ignorance is bliss applies'.
This is true, except in Terry Pratchit's 'Amazing Morris and his educated rodents', in the case of the rats that lived behind the unseen university, they are fully aware of their own mortality. Infact they even have their own grim reaper, or grim squeeker!
SO I MADE ONE!!!