The researchers note that chimps and other almost-human apes have a tendency to speak over the top of one another rather than engage in polite discourse. And that marmosets tend to chat more frequently with monkeys other than those whom they are mated with, which, when you think about it, is also an oddly human phenomenon.

And then you have chimpanzees. Scientists know that, chimps being highly playful creatures, most of them spend their time in groups jumping out from behind things, tackling each other, throwing their poop around, etc. Chimp stuff. But in a study of chimp behavior done by researchers at the University of Portsmouth, they found that chimps had two distinct kinds of "laughter" during play time. The ones that were actively engaged in play responded with ordinary laughter, but the other, nearby chimps made a much more forced, less intense, and more deliberate sound. In other words, it was more like the chimp equivalent of you going "heh" after your dad tells a particularly horrid joke.

Fuse/Fuse/Getty Images
Or when the alpha chimp tells his racist joke about the two bonobos who walk into a bar.

The researchers suggest that this is the way a chimpanzee who isn't actively engaged in the joke signals to the others "I, too, am having fun." In other words, they're being polite and assuring the others that they aren't moody assholes, a level of social etiquette that even some humans have failed to master.

We know what you're probably wondering (or, at least, one of several hundred things you're probably wondering): How do we know that the rats actually enjoy it and are not just squeaking in anguish and confusion? Well, first they conditioned the rats to be afraid of a certain audio tone -- the rats would freeze up and become nervous whenever the sound was played. But then, if they tickled the rats beforehand, the rats showed less physical and hormonal signs of fear when they heard the sound.

On top of that, the sounds that the rats made while being tickled were the same sounds they made when they were playing with other rats, suggesting that they are the rat equivalent of giggling. If the researchers stopped tickling, the rats would often chase their teasing hands around the tank to try to coax more tickles. There are social intricacies to be found as well, since the fun-lovers are more likely to spend time with like-minded fellows.

Furthermore, in a weirdly specific human parallel, the rats that didn't enjoy the interactions (and didn't laugh) tended to be neurotic and antisocial. And because scientists love playing God, they've selectively bred the most playful of the rats over the course of several generations to create a genetically super-ticklish, loud-laughing breed. That definitely won't make it weird when we poison or trap the little bastards years from now.

Vladimirs Prusakovs/iStock/Getty
On the other hand, we can start baiting traps with feathers instead of precious cheese or peanut butter.

Based on everything we know, cows are fat, lazy, and devoid of personality. They're smarter than most rocks, eject less methane than some military aircraft, but are otherwise only useful because a cow is the first step to a cheeseburger.

Ralf Nau/Digital Vision/Getty Images
And horses are much harder to tip.

In reality, these vacant-looking animals are more emotionally complex than given credit for, and have the capacity to form intimate social bonds. For the sake of animal welfare, Krista McLennan led a study that tracked how heifers respond to isolation. The doctoral student from Northampton University monitored several physiological parameters such as cortisol levels (which correspond with stress) and heart rate.

McLennan found that not only do cows prefer the company of other specific cows but that they even pick out best friends -- the cows' vital signs were most favorable when paired with their best friend, as opposed to a random stranger cow. Without their BFFs, they got sad. And with the noble heifers' demeanor negatively affected, milk production dropped. Just like every human on the Internet, cows can be socially awkward and become stressed when removed from their buddies. In the modern era of big-money farming, this scenario is commonplace, and cows are constantly separated then forced into new groups, like some kind of bovine speed dating.

Digital Vision./Digital Vision/Getty Images
"Wait, you like eating grass and staring blankly all day? No way, me too!"

We have no idea what society is supposed to do with this information (slaughter them in pairs, with their friends? That only seems weirder). We guess just keep in mind the next time you drive past a pasture that the cow you see grazing out there might have more close friends than you do.

You probably assume that human beings are the only creatures that hold ceremonies to grieve for the dead, and for the most part you're right. Funerals are a rather counterintuitive concept, especially given that, if there's something nearby that's killing members of your species, the last thing you want to do is gather all your friends and relatives in that place at the same time.

But there's at least one other animal that comes together in these times of anguish -- birds. Specifically, in a study conducted in 2012, researchers at the University of California, Davis discovered that the western jay has a tendency to hold a kind of funeral ceremony upon discovery of a dead colleague.

David Reimche/iStock/Getty Images
"And though Jay could not fly through that window, he will forever fly in our hearts ..."

Don't worry: They didn't study this by approaching a flock of jays and shooting one of them with a sniper rifle. Fortunately, the scientists already had a dead jay on hand. So they just dropped it where others were foraging and watched the live birds' reactions to it. When one of them discovered the dead bird, it let out a loud cry that attracted other birds of the species, which came from all directions to gather around their fallen comrade in what the researchers described as "cacophonous aggregations." The attending birds were so distressed that they halted their usual foraging behavior for more than a day. The scientists presumably watched their devastated little bird tears and wails of sadness and nodded, taking notes.

The birds were also able to distinguish between actual dead birds and ingenious wooden decoys made to look like dead birds. In much the same way as we don't fall to our knees in anguish when we see a mannequin lying in the street, the jays were at least savvy enough to realize when they were being taken for a ride. In another test presumably intended to drive the birds past the brink of insanity, the researchers mounted a dead but stuffed bird in the jays' foraging grounds, and the birds engaged in a kind of "mobbing" behavior that indicated that they thought it was alive, but sick in some way.

Wing-Chi Poon
Something like this, we imagine.

So, OK, they're not super-geniuses, but still, it's nice that they care.