Consider stoies of Animal Gratitude. Stith Thompson has a whole range of folktale types in this category, numbers 350-399. "Androcles and the Lion" is a famous example, but the internet is full of others:
Baby Elephant Thanks Little Girl After She Helps It Get Unstuck From the Mud
Mama bear hugs man who rescued cub. I actually watched this one, and in fact the mother bear did NOT hug the men who rescued her cubs from a freezing lake, since they sensibly did not get that close to the mother bear. But the title still emphasizes the imaginary gratitude.
The whale who danced beside her rescurers' boat. (That would be tale type 370, Animals Grateful after Release from Captivity.)
The crows who come back every year to visit the family that rescued them.
Besides all the tall tales there is actually what looks like one real story out there in this category, about a woman who took in bobcat kittens.
I put this post together quickly, but given the number of thes I have seen over the years, I'm sure I could have multiplied the examples if I wanted to.
File this under "the more things change, the more they stay the same."