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Bufo woodhousii

Page history last edited by PBworks 15 years, 5 months ago
Bufo woodhousii
     Woodhouse’s toad
 

Scientific Classification
 

 

 

 

 

Kingdom:
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Genus:
Species:
B. woodhousii

 

 

 

 

 

 

 

 

 

 

 

 

 

 


Image:  LA Dawson http://commons.wikimedia.org/wiki/Image:Bufowoodhousii.jpg

 

 


Identification: Adults have dry, warty skin. Adults average 2.25 to 5 inches in length. Males are often smaller than females. Parallel cranial crests are present between the eyes and the post-orbital crests connect them at a right angle, which contact the elongated, divergent paratoid glands. Adults have two black tubercles on each hind foot. A prominent yellowish or white line runs along the center of the back. Young toads may have no dorsal line and often have reddish brown warts. Two horny tubercles are located on the underside of the hind feet (Peterson C. R., 2000).

 

 


Eggs: Females lay up to 25,000 eggs per clutch, which are laid in two, long, intertwined strands (Peterson C. R., 2000). The eggs contain a single gel layer. The strings of eggs are often wrapped around submerged vegetation. The eggs are difficult to distinguish from Western Toad (Bufo boreas) eggs. Bufo Woodhousii eggs may be distinguished from the Bufo boreas eggs by the presence of a single gel layer (Western Toad eggs have 2) (Peterson C.R., 2000).

 

 


Tadpole: Tadpoles may reach approximately 1 inch in length. Tadpoles are dark brown and have black mottling on their bodies. The tail is dark on top and lighter ventrally (Animal Field Guide, 2008). The eyes do not meet the margin of the head. The snout projects outward beyond the limits of the main rounded body. 

 

 


 

                       

 Image: Kristi DuBois                                        Image: Charlotte C. Corkran                             Image: Charlotte C. Corkran                      Image: Charlotte C. Corkran

 

 

 


Distribution: Genus essentially world wide, more than 250 species; Bufo Woodhousii is a widespread species with 3 recognized subspecies (LeClere, 2005). Woodhouse’s toad occurs throughout most of central and southwestern United States. The elevation range of the full species is from below sea level to 8,500 feet (Animal Field Guide, 2008). This species is found thoughout norhern portions of Mexico, and northern shore of Lake Erie in Canada. The northwestern portion of the range is comprised of isolated, disjunct populations in lower elevated parts of the Columbia and Snake River drainages (Smith, 2007). Idaho populations occur along the western Snake river plain. There was a single historical record from Lewiston Idaho which suggest populations extended to the lower reaches of the Snake River. The lack of recent records within the vicinity of Lewiston suggests that this species no longer occurs in this part of the Idaho range (Smith, 2007).

 


 

 

 

 

Distribution map: courtesy of the U.S. Geological Survey

 

 


Habitat: Populations occur in desert-grassland and shrubland environments, habitats such as prairies, agricultural areas and brushy flats associated with water. This species is often found in floodplains or washes or riparian habitat (Smith 2007). However, this species is occasionally found at permanent ponds and lakes and in urban areas. Larvae are often located in large aggregations in pond and stream habitats in standing water (Peterson C.R., 2000).

 

 


Behavior: Tadpoles start out as herbivores; they eat organic algae, debris, suspended matter and plant tissue (Animal Field Guide, 2008). Adults are carnivores. Adults locate their prey by vision.  They use their tongues, which are attached to the front of the mouth, as a sticky slingshot to catch prey. Adults eat a large variety of small terrestrial prey such as: scorpions, bees, spiders, ants, beetles, and sow bugs. Adults will eat almost any small prey species that will fit in their mouths. Although the Woodhouse’s toad is primarily nocturnal, diurnal activity is not uncommon (Peterson C. R., 1997). Adults often burrow underground to avoid inhospitable conditions and often occur where soils are sandy or loose. In addition, adults use logs, rocks and other substrates to hind under. There are many predators of adults including: bull snakes, rat snakes, American bullfrogs, hawks, roadrunners, skunks, and many small mammals (Wikipedia, 2008). They are inactive during the cold months of the year such as fall, winter and spring (Peterson C. R., 2000). Adults often puff up their body to make themselves seem bigger than they are when approached by a predator. If that does not deter the predator, adults have long oval shaped parotoid glands which emit a white fluid that is toxic. The white fluid inflames the mouth and can cause nausea, irregular heartbeats, and in some cases even death (Animal Field Guide, 2008).

 

 


Reproduction: Breeding choruses may last a few weeks, and the timing of breeding depends in part on water availability and response to rain events. The timing of breeding also varies geographically. Fertilization is external. Breeding may occur from late March-July depending on the spring and summer rains (Smith, 2007). Breeding takes place in shallow bodies of water, which include streams, rivers, irrigation ditches, and sometimes temporary or seasonal pools. Adults may migrate up to several hundred meters between breeding pools and non breeding habitat. Adults reach sexual maturity in approximately 2 years. The call resembles a sheep’s call or a baby’s scream, lasting from 1-4 seconds (Peterson C.R., 1997).

 

 


Scientific study

Variation in Bidder's Organ Volume Is Attributable to Reproductive Status in Bufo Woodhousii

 

Rebecca M. Calisi

 

Journal of Herpetology

Volume 39, Issue 4, December 2005, Pages 656-659

 

 

This study examined changes in Bidder's organ volume in relation to reproductive status. Bidder's organ volume was larger in non reproductively active males, which suggested that cues associated with sexual maturity influence Bidder's organ volume. Black-pigmented throat served as an indication of reproductively active males. In addition, black-throated mals had significantly larger testes than nonblack-throated males. As a result, the researcher was able to use the black-pigmented throat as a reproductive status.

 

Forty specimens were used from the Arlington Collection of Amphibians. Specimens were collected over a 40-year time span during the breeding season months. Separate ANCOVA's to control for spatial and temporal factors were used. The length of he testes and Bidder's organ were measured using dial indicator calipers in both the right and left organs. The volume of testes and Bidder's organ were estimated using the formula for a prolate spheroid. 

 

There was a trend noticed in an increase in Bidder's organ volume during the months of March, June, and July. Testes volume was inversely related to Bidder's organ volume. Reproductively active males expressed a decreased Bidder's organ volume. Bidder's organ volume was significantly different in reproductively active males compared to non-reproductively active males.

 
Works Cited
Animal Field Guide. (2008, September 30). Retrieved September 30, 2008, from Montana Natural Heritage Program: http://fwp.mt.gov/fieldguide
 
Calisi, R. M. (2005). Variation in Bidder's Organ Volume is Attributed to Reproductive Status in Bufo Woodhousii. Journal of Herpetology , 656-659.
 
LeClere, J. (2005). Woodhouse's Toad-Bufo woodhousii. Retrieved September 28, 2008, from HerpNet: www.HerpNet.net
 
Peterson, C. R. (2000). Bufo woodhousii Woodhouse's Toad. Retrieved September 27, 2008, from Digital Atlas of Idaho: http://imnh.isu.edu/digitalatlas/bio/amph/anurans/buwo/buwofra.htm
 
Peterson, C. R. (1997, June). Photographic Identification Cards for Idaho Amphibians. Retrieved September 30, 2008, from Idaho State University: http://www.isu.edu/~petechar/idar/amphib.pdf
 
Smith, G. (2007). Classification Nomenclature Description Range. Pheonix: Arizona Game and Fish Department.
 
Wikipedia. (2008, September 4). Bufo Woodhousii. Retrieved September 30, 2008, from Wikipedia The Free Encyclopedia: http://en.wikipedia.org/wiki/Bufo_woodhousii
 
Woodhouse's Toad Bufo Woodhousii. (2005). Retrieved September 29, 2008, from Idaho Department of Fish and Game: http://fishandgame.idaho.gov

 

 

This page created by Cassidy Bair

 

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