What makes certain animals "so cute" and others - not so much?

Genetics??

All in the eyes & fluffiness.

Subjectivity.

I’ve always heard people explain “cuteness” as our biological wiring responding to baby-like features. (Big eyes, big heads, etc.) And/or, I’ve heard that baby-like features are cute because they’re nonthreatening. I’m not sure if that’s true or not.

I like comparing squirrels and rats, because squirrels are basically rats with fluffy tails. There are some differences in the skulls, too—a squirrel’s head is rounder, with larger eyes, so I guess we could argue a squirrel is better at tapping into our “biological wiring,” assuming it’s there… But it also may be perception, or at least informed by perception. Squirrels are usually seen as cute fuzzy tree-dwelling creatures, while rats are usually seen as ugly disease vectors that invade attics and gardens. Even so, pet rats are regarded as pretty cute and cuddly—rats without the disease or the nuisance, so rats without the threatening aspects.

As for me, my cute radar may operate a little too broadly, since I find ants, boa constrictors and bees pretty adorable. (Well, at least the bees are fuzzy with large eyes). Maybe that’s more a commentary on modern technologies/advances allowing me to not feel threatened by more creatures?

Your question made me think about the definition of “cute,” which I think has to do with smallness as well as attractiveness or emotional appeal. Some things are pretty or beautiful or even adorable (in the colloquial sense) without being cute. And vice versa. (When I think of art, “cute” would be a pejorative.)

I think the human analog is important. When we can see images of ourselves—and, sometimes better, our babies—in them, we’re drawn to them and want to hold and protect them. The big wide eyes, the fuzz, the helplessness—we respond to those things viscerally. I think we’re wired that way; it’s good for the survival of the species.

In fact, I think we’re wired to see any baby mammal, even baby warthogs, as cute. This comes out as an “aww” reflex that has been endlessly exploited by Disney and his fellows. How many children have been bitten by squirrels and chipmunks or geese and and piglets that were not going to gather around in a sympathetic circle and sing?

No doubt somebody has done a dissertation on this phenomenon.

Dictionary.com defines “cute”:

adjective, cuter, cutest.
1. attractive, especially in a dainty way; pleasingly pretty:
a cute child; a cute little apartment.
2. appealing and delightful; charming:
What a cute toy!
3. affectedly or mincingly pretty or clever; precious:
The child has acquired some intolerably cute mannerisms.
4. mentally keen; clever; shrewd.

Only the first two apply here; but there’s a seductiveness to “cute” that isn’t captured in those definitions and that feels manipulative to me. It’s why I generally dislike and avoid cuteness and don’t usually watch viral videos of animals acting like funny, charming miniature people.

I don’t think the little hamster is trying to manipulate you.

It is all about facial proportions

Fur (softness, cuddliness)
Big eyes
pleasing proportions

The eye of the beholder.

Truly inexplicable in that a Grumpy Cat gets more hits than Barack Obama.

I have no idea, but I totally want to snuggle my friend’s red-tailed hawk (she’s a licensed falconer) and I know full well he’d tear me to ribbons.

Neoteny, in a word.

Anthropomorphism. We are indeed wired to find babies adorable, and women are particularly vulnerable to this reflex for understandable reeasons. But it goes well beyond that. Consider for example the high premium we humans accord the face in measuring “attractiveness”. So powerful is our slavish obsession with this one aspect of we as people that trillions of dollars are diverted to plastic surgeons and the truly irrational cosmetics industry.