I’ve never seen a tan pig, and other mammals have so much hair you couldn’t tell.
Pigs burn easily in the sun, which is one reason they wallow in mud.
Yeah, I once knew a white whippet (named Elmo) who had fairly thin fur and he turned pink and red with too much sun.
Kinda pitiful, really.
I know that horses, and other animals with a thin layer of hair in the summer will get sunburnt. Dogs and other animals will get burnt on their noses, bellies, or ears, especially if lighter colored.
My dog’s nose is pink in the winter and pitch black in the summer. I assume it has to do with the amount of sun she gets…
Dogs can get a condition called “snow nose”: Technically called “hypopigmentation” (or snow nose, winter nose) it results from loss of sunlight, and causes the nose to fade to brown in winter; normal color returns as summer approaches. Snow nose occurs mainly in light-coated breeds; the color change can become permanent in older dogs. It is not associated with disease.
My one corgi gets it, the other doesn’t.
Interesting posts. I am not surprised to hear that animals can get sunburn, which is simply a radiation burn and would probably affect any mammal with exposed skin. But still haven’t heard about any that get a tan.
Implied in the information that certain animals can burn is the information that this means they don’t tan. If they could tan, they wouldn’t burn. Pigs, especially.
Other mammals like horses and dogs have heavy growth of body hairs that protect the skin from excess UV radiation, except for pigs, which evolved in a heavily shaded jungle/forest. Homo sapiens evolved away from heavy body hair, and thus melanocytes stepped up to fill the void.
So if you want to find animal species that tan, look for species that evolved in full sun, like on a grassland, but have skimpy body hairs.
Just off the top of my head, homo sapiens is the only one.
My greyhound’s nearly hairless belly gets very dark in the summer from laying out in the yard. I’ve considered sunscreen, but I only let her lay out for 15-20 minutes a day when it’s very sunny.
That’s cause we were the only ones dumb enough to leave the shade to go into the sun! 
Hell, sea mammals have it the best! I’m pretty sure dolphins are the smartest beings on the planet. They just swim all day long, eat some fish if they’re hungry, and then go have hot dolphin sex. Living the dream, man, living the dream.
And sometimes not-dolphin sex, if certain internet rumors are true.
According to a show I saw on sharks, they can tan. At least the baby ones which stick to shallow waters can.