Bullfrog Books

In Rocks, beginning readers will learn to identify different kinds of igneous, metamorphic, and sedimentary rocks. Photos and carefully leveled text provide defining details for each kind,… More →

How much weight can an elephant carry? What animal has the strongest bite? In Strongest Animals, beginning readers are introduced to the strongest animals across a variety of classes and… More →

In Seashells, beginning readers will learn to identify different kinds of seashells found on the beach. Photos and carefully leveled text provide defining details for each kind, such shape,… More →

In Slimy Animals, readers will learn about slimy animals, including snails and slugs, slime eels, and worms. A comprehensive Why Are Some Animals Slimy? back matter feature highlights… More →

In Gross Animal Habits, readers will learn about different bizarre animal behaviors, including blood-squirting lizards, spitting llamas, and gut-flinging sea cucumbers. A comprehensive… More →

In Stinky Animals, readers will learn about smelly animals, including stink bugs, skunks, and musk oxen. A comprehensive Why Are Some Animals Stinky? back matter feature highlights… More →

What's slower than a sloth? Could you beat a tortoise in a race? What's the slowest swimmer? In Slowest Animals, beginning readers are introduced to the slowest animals across a variety of… More →

What reptile fits on your fingertip? What animal might you need a microscope to see? In Smallest Animals, beginning readers are introduced to the tiniest animals across a variety of classes… More →

What animals use tools? How do orcas work together to hunt? Can elephants tell when a friend is sad? In Smartest Animals, beginning readers are introduced to the smartest animals across a… More →

What's the biggest bird? Is a blue whale bigger than an elephant? What's the tallest animal? In Biggest Animals, beginning readers are introduced to the largest animals across a variety of… More →

In Gross Animal Eaters, readers will learn about different bizarre animal diets, including dung eaters, blood drinkers, and body-munching parasites. A comprehensive Gross Animal Foods… More →

How fast is a cheetah? What's the fastest bug? In Fastest Animals, beginning readers are introduced to the quickest animals across a variety of classes and species. Vibrant, full-color photos More →