The lining of oral cavity is called oral mucosa and is different from the skin in the external surface.

The epithelium of both are different. Oral mucosa is adapted for sustaining heat.

Thanks, I wonder if oral mucosa of chimps or gorillas are so adapted.

Perhaps it is a common feature of oral mucosa to sustain more heat than skin in many animals.

In that case, it won't be a specific adaption in humans.

Hello, I share information with you, I hope it is useful for you, greetings

https://www.cso.go.cr/temas_de_interes/higiene/agentes/fisico/06_temperaturas.pdf

https://www.drugs.com/cg_esp/c%C3%B3mo-tomar-la-temperatura-oral-discharge-care.html

Alejandra Giselle Juárez-Rebollar

Thanks but I wonder if an English translation exists?