Here are 2 interesting tweets I recently stumbled across. Both are from the moderator of the Sofia The First wiki. For a lot of Disney Junior shows, if it's a girl in the leading role, she'll be human. If it's a boy in the leading role, then he'll be some sort of animal/creature. To give a few examples:
Doc McStuffins, Princess Sofia (Sofia The First), Kate (Kate And Mim Mim) Princess Elena (Elena Of Avalor) , Nancy Clancy (Fancy Nancy), Kit Secord (The Rocketeer), and Mira (Mira Royal Detective) are all humans .
Oso (Special Agent Oso), Henry Hugglemonster, Kion (The Lion Guard), Mickey (Roadster Racers series), Bingo & Rolly (Puppy Dog Pals), Kermit (Muppet Babies 2018), and Pip & Freddy (TOTS) are all animals/creatures (bear, monster, lion, mouse, dogs, frog, penguin and flamingo) .
There are some exceptions, such as with Jake And The Neverland Pirates and Miles From Tomorrowland being humans, and Sheriff Callie and Vampirina respectively being a cat and a vampire, but that's it.
Why do you think that is?