But the beastkin are mammals... Turtles and Tortoises are reptiles. All reptiles are cold-blooded, including tortoises and turtles. Wyrms would be cold-blooded too, but they also produce flames, so while they may be ectothermic, the ones living in cold regions would still have a source of heat through their fiery breath.

As a matter of fact... the top image for ectothermic/cold blooded on wikipedia is turtles sunning.

https://en.wikipedia.org/wiki/Ectotherm

I'd really like to petition for Adamantoises to be moved to scalekin. Turtles don't have mammary glands like an Aldgoat would.

Another thing to keep in mind, Skies, is that many of the largest creatures to have existed were cold-blooded reptiles. Tyrannosaurs Rex... The Sauropods like Brontosaurus... Size has nothing to do with something being cold or warm blooded.