There might be a psychological explanation as to why we find these creatures so adorable.

One study from 2007 found that the amygdala, a part of the brain that is involved in processing fear, reaches significantly higher activation levels when a person is shown pictures of sharp everyday objects (e.g., angular corners of a sofa) compared with their curved contour counterparts.

So we might perceive round animals as less dangerous.

Google data designer Manuel Lima believes the reason for this comes from our days as cave people.

"[Circles are] softer, they provide some safety, as opposed to angular shapes–the teeth of an animal, the hard shape of a rock. Those are signifiers of danger," he once told Fast Company.

Other research also supports the notion that we connect the shape with happiness.

In 1978, psychologist John N. Bassili conducted an experiment in which he added luminescent dots to the participants' faces.

When the people were asked to perform expressions of happiness, the dots would form into curvilinear, upward, open shapes, while expressions of anger created downward, angular forms.

Lima's last theory also talks about the curved shape of the human eye, which slightly distorts the world at the edges of the "frame"–similar to the distortions in a crystal ball or a fish-eye lens, though not quite so exaggerated.

Circular shapes tend to complement this physical construction of the eye. “[Circles] fit so well into that visual apparatus,” he said.

The subreddit 'Round Animals' was created in 2018, the same year when AV Club ran an article on them too.

In it, writer Clayton Purdom said these critters' cuteness is "defined not by their species, nor by some abstract spiritual quality," but it transcends the regular characteristics and, "like the true nature of pi," remains universal.

We couldn't agree more!