Toad, Houston

Bufo houstonensis

phylum: Chordata

class: Amphibia

order: Anura

family: Bufonidae

status: Endangered, IUCN Endangered, ESA

range: USA (Texas)

Description and biology

The Houston toad is a medium-sized toad. Females average 2.1 to 3.1 inches (5.3 to 7.9 centimeters) long. Males are slightly smaller, averaging 1.8 to 2.7 inches (4.6 to 6.8 centimeters) long. The toad is usually light brown in color. Sometimes it has a reddish hue. It is covered with dark brown to black spots each containing one or more warts.

Adult Houston toads feed mainly on insects such as ants and beetles. Tadpoles (toads newly hatched or in their larval stage) eat algae and pine pollen. Some snakes and turtles may prey on the toad, and certain fish may prey on its eggs.

During mating season, males make a high-pitched trill to attract females. This calling can begin as early as late January, and breeding takes place when the air temperature reaches around 57°F (14°C). Females lay their eggs between mid-February and late June. Each female will produce 500 to

6,000 eggs. In order for tadpoles to develop, breeding pools must remain intact for 60 days.

Habitat and current distribution

Biologists (people who study living organisms) believe the Houston toad survives only in Harris, Bastrop, and Burleson counties in Texas. The largest concentration of these toads is in Bastrop County, particularly in Bastrop and Buescher State Parks. Biologists have estimated the total population there to be 1,500. The population in Burleson County is believed to be very small. Although no toads have been sighted in Harris County since 1976, biologists are hopeful that some still exist there.

The Houston toad occupies a variety of aquatic habitats, including lakes, ponds, roadside ditches, flooded fields and pastures, and temporary rain pools. Because it cannot dig burrows very well, the toad inhabits areas with sandy soil, such as pine forests. When not mating, the toad finds shelter in the sand, in burrows, under logs, or in leaf debris.

History and conservation measures

The Houston toad was discovered in the 1940s. Just one decade later, because of severe droughts that struck Texas, it was thought to be extinct. In 1965, it was rediscovered in Bastrop State Park.

This toad does not adapt well to dry and warm conditions, so these droughts severely reduced its population. Since then, the number of Houston toads has been further reduced as pine forests have been cleared to create farms and communities. The runoff of pesticides and herbicides used on farms and in residential areas also threatens to destroy what remains of the toad's habitat.

Conservation efforts for the Houston toad include protecting its remaining habitat and reintroducing it into areas in its former range.