Gastrophryne olivacea02
 Photo: Stanley Trauth 2007 (wikipedia)

A few years ago, I built several ponds near my house at the Double Helix Ranch, hoping that frogs would colonize them and I could enjoy the sound of frog calls outside my window. Several different species have come and bred there including Strecker's Chorus frogs (Pseudacris streckeri), Grey Treefrogs (Hyla chrysoscelis), Rio Grande Leopard frogs (Rana berlandieri), and now Great Plains Narrowmouth toads (Gastrophryne olivacea).

The Gastrophryne is something I’ve been especially happy about, as they are cool little frogs. “Gastro,” of course, means stomach, and “phyrne” is derived from the ancient Greek word for “toad.” So they really should be called “tummy toads” which would be a fitting name, since they are basically big tummies with tiny heads attached.

In Texas, Gastrophryne breeding takes place from mid-March to September in water bodies stimulated by rainfall, as damper environments allow migration. They breed in ponds, springs, flooded fields, and drainage and roadside ditches. During mating, males attach to females by a special “glue,” a secretion produced by specialized cells in the skin of the toad’s venter (the underside).

GastrothecaEggs 
 Gastrophryne eggs. Photo: David M. Hillis

These toads lay their eggs as a surface film, which is a common strategy among frogs that breed during warmer times of the year. This is because of warm water has low concentrations of oxygen, so the eggs laid on the surface get plenty of oxygen from the air.

The females can lay between 650 to 2100 eggs that form clusters of 100 to 200. These eggs will hatch in two days to become tadpoles, a stage they will be in for 28 to 50 days. Adult toads reach sexual maturity at 1 to 2 years of age. A sexually mature male has a dark distensible throat pouch, meaning the pouch can stretch and expand. These toads can live 7 to 8 years in the wild but most don’t live this long.

Adult toads of these species are ant eaters and have an interesting mutualism with tarantulas. They live in tarantula burrows, unharmed by these big spiders, and the toads keep the burrows ant free. If danger lurks, the little tummy toad scampers beneath the tarantula for protection!

Gastrophryne and tarantula
 "Tummy toad" and tarantula. The toad is in the upper left corner. Photo: David M. Hillis