Dear Aunt Debbie,
Your last post gave me a great little epiphany moment -- all this time, all these many readings of Bow-Wow, I had just assumed the dog was male. But you're right -- there are no gender cues at all. What does it take for an animal to read as female? Long eyelashes, I guess. Eleanor has already consciously picked up on the eyelash cue when assigning gender to animal characters. If it looks neutral, it's probably male.
Which is why your post reminded me of the moment that I figured out that Piggie, of Mo Willems's most excellent Elephant and Piggie series, is female.
The Elephant and Piggie books are cartoony stories about the adventures of Gerald (the elephant, a worrywart) and Piggie (the pig, mostly a happy-go-lucky sort, but prone to fits of anger). They're longer than Willems's Pigeon books, and all the text is dialogue, in speech bubbles. (They lend themselves to staged readings.)
Are You Ready to Play Outside?, in which Piggie's great enthusiasm for playing outside is dampened (ahem) by a torrential downpour. She is crushed. She is furious. She hates the rain. But with Gerald's help and after seeing two really happy worms playing in the rain, Piggie decides that rain is actually wonderful! Just in time for it to stop raining.
I'm using the female pronoun here, but on first reading (and second, and fifteenth), I read both characters as male. They have a kind of odd-couple feel that makes me think of buddy movies, Laurel and Hardy, Frog and Toad. Piggie has no secondary sex characteristics -- no curly eyelashes here -- and neither character wears clothes. Gerald is gendered by his name; Piggie isn't. Because the whole book is a dialogue between two characters, it's pretty easy to avoid pronouns.
We read other Elephant and Piggie books: There is a Bird on Your Head! is my other great favorite, although there are many. I love the declarative titles. It wasn't until we found I Am Invited to a Party! at the library that I saw it: when Piggie is invited to a party, and she and Gerald dress up in a wide variety of outfits to prepare, she wears women's clothing. I think there may also be a female pronoun in this one; I don't have it at home to check. The jacket copy confirms Piggie's gender as well, where others don't.
So, interesting choices by Mo Willems. Why create a pair of male-female best friends and leave the gender of one, but not the other, ambiguous for several books? Or did Piggie read as female to Willems from the beginning, and would Eleanor's and my gender assumptions about her surprise him?
In any case, they're a nice boy-girl non-romantic pair.