Zoo celebrates the world's first IVF Houston toads

Zoo celebrates the world's first IVF Houston toads

Meet Uri and Viola!

The Fort Worth Zoo and partners from Mississippi State University are celebrating the world’s first Houston toads produced via in vitro fertilization (IVF). The first two toads produced using frozen-thawed semen, Uri and Viola, are being reared at the Zoo and their siblings were released in Bastrop County, Texas.  They were named after the two Texas winter storms that the team endured while working on this important research. This is a huge conservation milestone as it will allow the Fort Worth Zoo and program partners to expand the genetic diversity of the captive population and maximize number of offspring each year for reintroduction efforts.

The Houston toad is a small amphibian, endemic to central Texas, found in about eight of Texas’ 254 counties. This toad is also an endangered species, with an estimated 400 remaining in the wild. Habitat loss and alteration are the biggest threats facing this little toad. The Houston toad is known as a “habitat specialist,” which means it requires very specific environmental conditions for it to live and thrive. It needs loose, yet deep, sands as well as canopy cover, native grasses and water sources for living and breeding. These specific conditions have been converted for agricultural and commercial use and have reduced the toad’s specialized habitat. In addition to habitat alteration, the 2011 Bastrop wildfires nearly wiped out the entire population of Houston toads. The Fort Worth Zoo is one of only four facilities breeding this species in professional care, resulting in offspring for reintroduction efforts. To date, the Zoo has placed more than 87,000 tadpoles back in Bastrop County. And in 2021 alone, a grand total of 117,346 eggs and 14,572 tadpoles were released into the wild! (And yes, Zoo staff counted each and every one of those eggs and tadpoles.) 

As an indicator species, declines in the Houston toad’s populations suggest that the balance of their ecosystem is off. And when populations of one species start to decline, it signals declines in others may follow. Ultimately, the Zoo will continue breeding and reintroduction efforts to bolster populations of the Houston toad in 2022 and beyond.