Cats

Some people ask, "Are cats social?"

Only a cat-hating person could ask such a question.  Cats have such a wide array of social skills, they domesticated us (or at best, it was mutual).

Cats did not have to be bred to be compatible with (some) people.  They just figured that out.

They clearly display signs of many if not most human emotions.   Very much like us, they can also hide their true emotions (though most often, they don't, they love to show their emotions much more than we do).

Cat society is a complex hybrid.  All cats are territorial, but females tend to stick together, males are engaged in endless territorial conquest or defense with other (especially male) cats.

Very much like humans, male cats spend much if not most of their waking time determining "who owns what."  With cats, these issues are ultimately solved by one on one fights.  Ultimately, one cat relents, at some level of being defeated.  Afterwards, first they will hide, then they will pretend no injury or pain (to the point of very serious injury which will cause extreme lethargy) to the best of their ability, since they never want to show weakness.  Their fur tends to hide the damage, and cats 'heal' fast, but sometimes too fast for the best result.

After some number of fights, boundaries may be well enough established that are no more big fights, just a few aggressive moves are all that's necessary.

Every cat will fight hardest for something, and a stronger cat will ultimately let some far flung and less desirable properties go without much fuss, so there ends up being something for everyone, up to a point.

There is never any 3rd party involvement.  Cats settle all disputes one on one.

It's less "civilized" in that it doesn't rely on anything like "civilization."  It's hard and could be construed as cruel by human standards, but cats rarely kill or harm other cats much, and there's usually something somewhere for every cat up to cat explosion population levels and then some.

It's a society that relies ultimately on a ubiquitous and strict form of one on one fighting to answer the ultimate question of who owns what, but few are killed or even hurt much.  Left to their own devices, without any animal control or predators, the number of cats will reach the total number cats "sustainable" and be around that depending on time of year (the hardest freeze may kill off a few, then there will be spring births, so new cats will always appear to replace old who generally disappear without a trace just before their jig is completely up).

Much human power ultimately relies on aggression as well, but in many different regimes--few of which are one on one fights, and it can and often does kill in the process and harm in numerous ways (for example, wars).  According to some (ie Steven Pinker) fewer fights and total deaths, but more singularly deadly fights, during the increase in complexity of human civilization (ie history).  Complex civilization has also produced mind boggling un-sustainability which is transforming the planet and already causing mass extinctions.