Bestiality

So I was lazing in bed with my lover the other day when it occurred to me how inconsistent our cultural predispositions are with regard to personifications of animals, and how we relate that to each other. In other words, why is an attractive girl called a fox and an unattractive girl called a dog when foxes and dogs look basically the same? It certainly doesn't end there, nor just for women. I was thinking about the major types of animals and how cool or not cool it is to be called each one: Mammals, Birds, Reptiles, Fish, and Insects.
Mammals:
Mammals are strange from this perspective and require a lot of thought. Most mammals are covered in stinky fur and have a layer of fat for protection. So calling your lover by the name of a mammal is usually a bad idea, save for a few animals that are either smooth and pretty or effective predators. Or if you happen to be influenced by Asian Shintoist culture, you might see some animals as having certain attributes. I’m going to focus on the western perspective here.

Carnivores:
As a whole, meat-eaters are large and powerful. So most men don’t mind being referred to as a feline, canine, or ursine. But women prefer to think of themselves as light and discrete, so while kitten or tigress is a compliment, I wouldn’t try puppy.
Smaller carnivores have a harder time getting props, mainly because they tend to scavenge. Mongoose kill snakes and are proud creatures, so they are positive, but weasels are not. Foxes and minks are pretty enough to pull off being positive, but raccoons are nasty.

Herbivores:
No men like to be referred to by any of the herbivores. A compliment to a women might be to compare her to one of the shinier and more graceful hoofed grazers, such as a doe. Being likened to any farm animal is always insulting because we know that farm animals stink and are dirty. Hence the terms sheep, cow, chicken, pig and ass are all mean things to call someone.

Omnivores:
This is obviously a large group, so I’m going to split it out.

Primates:
Primates are intelligent and successful in the wild. However, they're unappealing solely for the reason that their faces are just close enough to human to look like retarded humans.

Rodents and any small, furry cousins:
Any non-domestic small mammal is guaranteed to be covered in grime because they are so close to the ground. However, rodents are small and are sometimes considered cute if clean. Rabbits usually pull off clean the best, so girls don’t mind being compared to bunnies and men don’t mind being compared to jackrabbits.
Rat, shrew, lemming and other all have very negative connotations.

Medium-sized mammals:
Badgers, beavers, wombats, raccoons, opossums and the like don’t really have much personification unless they have wandered into cities, where they are considers gross pests.

Aquatic Mammals:
Except for the dolphin and the otter, mammals that spend long amounts of time in the water have a lot of blubber to protect themselves from the cold. So calling someone an aquatic mammal is saying that they are fat.

Birds:
As a general rule almost all birds are fast with skinny legs, traits that few humans find undesirable. Some birds are gangly, so that can be an insult, but for the most part they are positive comparisons. Eagles, hawks, swans, songbirds, are all nice comparisons. There are of course birds that we know too well, like chickens or turkeys, and scavengers, like pigeons, seagulls and crows, but for the most part birds are positive.

Reptiles:
Very specific connotations.
Snakes are sneaky and untrustworthy.
Lizards are sedentary and small.
Turtles are slow.
Crocodiles are scary.
Calling someone by a reptile name is universally insulting.

Fish:
Graceful in the water, but surprisingly pungent on land, and always slimy.
I've never called anyone a carp or salmon, but I bet they'd think I was talking shit.

So personification of and comparison to animals is largely reliant on the comeliless of the animal. Visually, this dictates non-shaggy fur, feathers or skin. Olfactorily, this dictates both a relatively clean animal and a non-scavenger.