ROYAL OAK, Mich. – The Detroit Zoological Society’s breeding program for the Wyoming toad has produced a record 3,945 tadpoles for release into the wild in its efforts to preserve the federally endangered amphibian.
“This is the largest number of tadpoles we have ever sent back to Wyoming,” said Marcy Sieggreen, Curator of Amphibians at the Detroit Zoo. The majority of the tadpoles were released into the Laramie Basin, a protected Wyoming wetland, while 16 were reserved for future breeding at other facilities.
“The tadpoles are returned to Wyoming before the middle of July so they have plenty of time to grow and metamorphose in the wetlands where they’ll live. It takes them approximately four to five weeks to change into toadlets,” said Sieggreen.
The Wyoming toad (Bufo baxteri) is a dark brown, gray or greenish amphibian with small, dark blotches. The average length is 2.2 inches, with the females slightly larger than the males.
Once abundant in the wetlands and irrigated meadows of Wyoming’s southeastern plains, the Wyoming toad was listed as extinct in the wild in 1994, meaning populations are no longer producing offspring that survive to adulthood in the wild.
The cause of the declines are not well understood, but it is likely that more than one factor contributed to the situation in the past, with habitat loss and infectious diseases suspected as major drivers.
In 2007, the Detroit Zoological Society’s collaborative breeding program for the Wyoming toad was No. 1 on the Association of Zoos and Aquariums list of the Top 10 wildlife conservation success stories. The breeding partnership has successfully released more than 6,000 tadpoles, toadlets and toads in Wyoming since the program’s inception in 1995.