Most people know what frogs are, and many have very different opinions about them. Some find them fascinatingly beautiful creatures while others would just as soon have no contact with them. Frogs turn up in forests, ponds, meadows, fairy tales, and dissecting pans in biology labs, and their legs can sometimes be found on dinner plates in fancy restaurants. There are more than 7000 species of frogs and toads that exhibit a remarkable diversity of appearance and behavior.
Frogs and toads (terms used interchangeably in different parts of the world) belong to the order Anura, which comprises nearly 90% of species in the phylum Amphibia. We tend to think of frogs as leapers, but some move by digging into the ground, swimming, climbing, and even gliding. Frogs have a complex life cycle, involving completely aquatic larval stages with oxygen-absorbing gills. Through a fascinating metamorphosis, replacing the tail and gills with limbs and lungs, the amphibians are transformed into terrestrial animals that take in oxygen through lungs and skin.
In reading this book, it becomes apparent that frog lives matter. Many frog populations are declining, and scientists believe that this is an indication of a “major global extinction event&the Sixth Mass Extinction.” Contributing to these declines are habitat destruction; climate change; the use of frogs as terrarium pets (particularly brightly colored ones), in biological and medical research, and as a source of protein food for humans; and the threat of amphibian diseases, particularly chytridiomycosis, a serious fungal disease that spreads quickly and affects many species.
The heart of the book is the section devoted to 600 species of frogs and toads, each one being showcased on a full page. The pages lead off with a gray map on which green patches show the species’ world distribution. It is interesting to note that most of the species are found only in very small areas around the globe. Next to the map, a chart lists the family, alternative names of the species, locations where it is found, habitat for both adult and larval forms, and its conservation status.
Below the map and chart are the scientific and common names as well as a drawing of the specimen and size ranges of adult males and females. A species description highlights important aspects of its appearance and behavior, and a discussion of similar species provides more information on how species are distinguished from each other.
A life-size color photograph of the organism adds to the page's appeal. When the image is too small to see details, an enlarged photograph is also included. If life-size is too large for the page, only the front portion of the specimen is shown and a smaller complete image is included. The legend that accompanies the picture describes specific external features that would be useful in identifying a specimen.
This volume is just plain fun to read. There seems to be no end of opportunities to learn about the diversity of frog appearance and behavior in the 600-page feature section. For example, most people are not aware of the incredible array of variable-pitch frog sounds that include peeps, chirps, quacks, quonks, quars, clicks, eeks, buzzes, boops, wroops, and many others.
There are too many attention-grabbing facts to include in a review. But this sampling might pique a curiosity to read the book. The eggs of the Surinam toad, a frog that looks like a dead leaf, develop into tiny frogs inside pockets on their mother's skin; male Italian tree frogs gather in a “lek,” where the females select mates based on those that put the greatest energy in calling; the turtle frog lives most of its life deep underground; the fringe-limbed tree frog, a bright green frog with yellow polka dots, lays its jelly-like egg masses on the undersides of tree leaves; Rosenberg's gladiator frog has a sharp spine on each forelimb, which is used to puncture the ears and eyes of its opponents in a fight; and the cryptic sand frog gets its name from the fact that its tympanum is hidden under the skin.
New species are still being discovered around the world and, for some, the known information is incomplete. The rough horned frog has never been observed breeding and its developmental pattern is a mystery; the eggs and tadpoles of the critically endangered Somuncura frog have never been described; and scientists still don't know whether it is food-getting or breathing that cause the tadpoles of Perret's egg frog to hang in the water, their open mouths at the surface.
The book includes a glossary, a list of print and electronic resources related to amphibians, and three indexes – common names, scientific names, and family names. Unfortunately, it does not have a subject index. It would make an especially handy reference book for biology or environmental science classes at the college and high school levels. Some middle school students who are interested in frogs would enjoy the pictures and the interesting descriptions of individual species.
Although this engaging volume is fascinating to read, it is “heavy” reading. Weighing in at 4.9 lb (2.2 kg), it could weigh down a tote bag or backpack and might not be a first choice for taking on an airplane or going to the beach. However, a Kindle edition is available.