[sdwr]

I believe the main biological lever is retaining juvenile features as adults, physically as well as mentally (like with dogs). What we see as cute is an honest signal that they are more child-like: less aggressive, more trusting and pro-social.

[LeifCarrotson]

I also think that this is the central cause of a wide variety of domestic/cute adaptations. There are too many separate features to believe that raccoons and dogs and cats and a dozen other species all select for these same elements independently.

I no longer have the book on hand, but read a few months ago that this correlation between juvenile traits and domestication was one of the main theses of Barrett's "Supernormal Stimuli" in Chapter 4. She cited a few studies of fox domestication [1], [2] and other works to support these theories.

[1]: https://courses.washington.edu/anmind/Trut%20on%20the%20Russ...

[2] https://www.cell.com/current-biology/fulltext/S0960-9822(05)...

[skeezyjefferson]

animals werent kept as pets until recently - they were all (dogs, livestock etc, cats technically) working animals.