The Couch's Spadefoot is ecologically one of the most interesting but least documented species of toads in the United States. The lives of these amphibians remain largely hidden, as adult spadefoots may spend as long as 10 months of the year underground, coming onto the surface only at night after warm rainfall. The name "spadefoot" comes from the dark, spade-shaped tubercle on each hind foot that the spadefoots use to loosen soil as they dig themselves feet first into burrows.
The Couch's Spadefoot occurs in short-grass plains and mesquite savannahs in the southwestern United States and Mexico. Although already known, this species was first discovered in Colorado thirty years ago. The Colorado populations of Couch's Spadefoot in Otero and Bent counties appear to be isolated from populations in nearby states by more than 100 miles.
 |
 |
| Distribution of Couch's Spadefoot in Colorado. Red Circles: previous distribution records; Blue Triangles: distribution records from 2005 to 2006. |
|
In the past few years, Couch's Spadefoot has been discovered in additional locations that considerably expand the known range within Colorado (see map). In June 2005, Dr. Lauren Livo, a herpetologist in the University of Colorado Department of Integrative Physiology, found a female Couch's Spadefoot (shown above) from Las Animas County. This spadefoot represents the first record from the county and the southernmost record in Colorado to date. A year later, the species presence in Prowers and Pueblo Counties was also confirmed, extending the range further east and northwest.
Due to its localized distribution and limited numbers, Colorado Division of Wildlife lists the Couch's Spadefoot as a Species of Special Concern, and possession is prohibited without a special permit. In such scenarios, photography is particularly helpful to document these animals.
Color pictures of toads in conjunction with precise documentation of their locations (i.e., geographic coordinates), dates, habitat, and other field observations are all scientifically valuable and worth archiving as vouchers in a museum. In fact, the picture of the Couch's Spadefoot shown here is deposited and catalogued at the University of Colorado Museum of Natural History in the Zoology Section's Ancillary Collection. The range extensions and new county records of the species, as well as citations of their photographic vouchers were published in the journal Herpetological Review in 2006.
Although the Couch's Spadefoot has a limited distribution within Colorado, the recent range extensions demonstrate that we have more to learn about the natural history of this amphibian.
For previous Objects of the Month, check out our Archive.
