Doesn't it minimise your surface area?

... maximize the surface area to volume ratio

No. Minimize.

why would you ai generate a tumblr post...

You can estimate the ambient temperature in a photo of a sleeping cat from the cat’s pose: if it’s cold, they’ll form a loaf to conserve heat, and if it’s hot, they’ll sprawl out to dissipate it.

Yes, and it works both ways. Bergmann's rule basically says that within a group of related species, the ones living in cold climates tend to be bigger and heavier, those in hot places tend to be smaller. The reason is geometry: as a body gets bigger, its volume, and with it the heat it produces, grows with the cube of its size, but the skin radiating that heat only grows with the square. So being big and chunky is a great way to keep warm, and being small gives you way more skin relative to what's inside, which cools you down relatively speaking. This effect is increased by Allen's rule according to which animals of the same group in cold climates tend to have shorter ears, tails and limbs, those in hot places have longer appendages. See the Arctic fox vs. the fennec to get an impression.

At the same time: giraff

Its a snow poff

I'm not a baker but aren't loaves of bread baked in high temperatures?