Nevada Fish & Wildlife Office
Pacific Southwest Region

Amargosa Toad

(Bufo nelsoni)

Class: Amphibia
Order: Anura
Family: Bufonidae
Genus: Bufo
Species: nelsoni
Length: Males tend to be smaller, reaching 3 to 4 inches while females may reach 3.5 to 5 inches
Lifespan: Adults may live 9 to 12 years
Feed: invertebrates including spiders, insects, and scorpions
Habitat: Oasis Valley, Nevada, specifically along a 10-mile stretch of the Amargosa River and upland springs.
 

Life History:

The Amargosa toad is a member of the family Bufonidae which includes North American true toads. Eggs usually become tadpoles within two weeks of hatching, and tadpoles transform into immature toads in about four to eight weeks, or faster in warm waters. Sexual maturity is reached at two to three years and adults may live 9 to 12 years.

The dorsal (top) body of the toad is warty with black speckling or asymmetrical spots. Background coloration ranges from buff to olive and may vary considerably among individual toads in the same population. A light, mid-dorsal stripe occurs along the backbone. Underneath the toad is whitish with scattered blotches that merge above the legs to form the appearance of “pants”. Males tend to be smaller, reaching 3 to 4 inches (75 to 90 mm) while females may reach 3.5 to 5 inches (90 to 120 mm). Unlike most frogs and toads, the Amargosa toad is voiceless except for “release calls” or chirps made by males when grasped below their forelimbs by another toad or human.

 

Distribution and Habitat:

 

The Amargosa toad occurs only in Oasis Valley, Nevada, specifically along a 10-mile stretch of the Amargosa River and upland springs. The Town of Beatty occurs at the southern end of the toad’s range.

The breeding season for the Amargosa toad begins in mid-February when egg clutches are laid. A female may lay up to 6,000 eggs in a single clutch, which appears as a long strand of black dots intertwined among vegetation along the edges of a slow-moving stream or shallow body of water. Toads require relatively open water that persists long enough for the tadpoles to metamorphose into toadlets and leave the water. Breeding activity tapers off in the summer and ends in July. The eggs typically develop into tadpoles within a week, and tadpoles into toadlets in about 4 weeks.

Adult toads forage at night along the water’s edge and adjacent upland areas. Toads eat invertebrates including spiders, insects, and scorpions. During the day, Amargosa toads typically take shelter in burrows, debris piles, or dense vegetation.

In 2000, a Conservation Agreement and Strategy (.95 MB PDF) was completed for the toad and other species that co-occur with the toad in the Oasis Valley such as the Oasis Valley speckled dace, a small native fish. This document was prepared to ensure the persistence of the toad and other species in the area, and provide management guidance to prevent the need to protect the Amargosa toad under the Endangered Species Act.

 

Threats:

 

Major threats to the toad include water diversion and use, habitat degradation or loss, and non-native predators such as the bullfrog and crayfish.

 
Please Note: If you are experiencing difficulty in opening Adobe PDF documents, please right-click on the link and select the 'Save Target As' option.
 

Actions / Current Information:

 

07/20/10
  • Questions and Answers Amargosa Toad 12-Month Finding July 20, 2010
     
  • News Release for Endangered Species Act Protection Not Warranted for Amargosa Toad
     
  • 12-Month Finding on a Petition to List the Amargosa Toad as Threatened or Endangered
         
    09/10/09
  • Questions and Answers Amargosa Toad 90-Day Finding
     
  • News Release for Possible Protection Under the Endangered Species Act
     
  • 90-Day Finding on a Petition to List the Amargosa Toad as Threatened or Endangered
         
    05/14/07
  • Amargosa Toad Habitat and Movement Corridors (1.75 MB PDF)
         
    09/2000
  • Conservation Agreement for the Amargosa toad (Bufo nelsoni) (.95 MB PDF)
    Last updated: April 16, 2014