While animal biodiversity is declining globally, cultural representations of animals are highly prevalent in society and play an increasing part in shaping children’s perceptions of animal diversity. We studied animal portrayals in children’s picture books in the Netherlands, and coded over 2,200 animals from 217 award-winning books. We found a strong bias toward vertebrates, mammals in particular. Mammals were featured more often than other animals, played more prominent roles in the story, and were visually and textually specified more strongly. Furthermore, exotic and domestic species outnumbered native species. Picture books currently are likely to reinforce children’s perceptions toward only a small part of animal biodiversity. While we realize that picture books have other primary aims, picture book makers could be inspired and encouraged to diversify and specify their portrayals of the natural world. This would broaden children’s perceptions of the animal kingdom and could help foster lasting connections to biodiversity.