The largest rodent on earth lives in a swamp surrounded by jaguars, caimans, and anacondas, and has decided that none of that is going to affect its mood.
This is the part people miss. The capybara is not calm because nothing is happening. The capybara is calm because it has looked directly at everything that is happening and declined to participate. Peace like that isn't luck. It's a position.
It is also, somehow, the one animal every other animal likes. Birds, monkeys, turtles, ducks, some cat with nowhere better to be — they climb on top of a capybara and go to sleep, and the capybara does not acknowledge it. It's a public bench that happens to be breathing.
It looks like a loaf of bread with legs and swims like it was born there, which it basically was. Webbed feet, semi-aquatic, capable of sitting submerged with just its nostrils above the waterline for as long as the situation requires.
And it's loud. Whistles, barks, purrs, squeals, clicks — an unreasonable amount of noise from something that looks so profoundly done. They say that on a full moon it tilts its head back and howls at the sky.
Nobody fact-checks a guy that relaxed.