[larmstrong]

Reptiles (and other ectothermal vertebrates) will “artificially” give themselves fevers by staying in heat sources longer when they’re fighting an infection. It’s called a behavioral fever.

https://pubmed.ncbi.nlm.nih.gov/27381718/

[Nick87633]

I've definitely felt this before, The hot soup, hot tea, sweatpants, sweatshirt, wool hat, get-in-bed I feel like I'm about to have a fever reflex.

[bitwize]

I tend to get chills with my fevers. Maybe "chills" in ill mammals are similar instinct, to provoke the urge to bundle up and get warm when it isn't necessary, thus instigating a fever?

[tomcam]

So what I did that in middle school all the time. Kidding!