Kelly has an interesting post, about the recently announced study, "Gender Stereotyping and Under-Representation of Female Characters in 200 Popular Children's Picture Books: A 21st Century Update."
The comments to her post are excellent and worth your attention as they ponder the study's methodology.
I for one, am concerned about rampant specism in children's books. Honestly, cute little pigs, adorable bunnies, playful monkeys, soft feathery ducklings seem to dominate picture books. Happily, it is not all bad news for the fur and feather challenged. Ants have made some gains in recent years and seem to be gaining a small foothold with young readers.
There is much work to be done though. If it were not for Pond Scum, where would salamanders be? Pity scavengers too, have you read a tender tale about hyenas recently?
I think there should be some studies (or maybe there already have been) on this looming issue.