The Houston toad (Bufo [Anaxyrus] houstonensis) is an endangered amphibian native to east-central Texas.1 The Houston Zoo’s amphibian conservation quarantine facility was established to head start wild-collected egg strands, serve as an assurance colony, and provide a site for captive propagation and egg release to the wild. Thus far, body condition scoring (BCS) has been primarily used in domestic mammals such as bovines, equines, canines, and felines. This project combines basic BCS principles used in domestic mammals with toad-specific parameters to create a body condition sheet for the adult Houston toad. A total of 28 adult female toads and 12 adult male toads were observed and measured for this project. Observational parameters included degree of pelvic bone protrusion, degree of parotoid gland protrusion, body fat amount, muscle mass amount, and abdominal size. Measured parameters included body weight (BW), snout to urostyle length (SUL), and head width (HW). Measured parameters were taken from each adult Houston toad and averaged together to create an ideal BW:SUL:HW ratio. The combination of observational parameters and ideal ratios was the basis of the BCS system. A healthy BW:SUL:HW ratio for an adult Houston toad is 2:3:1. Gravid adult female Houston toads should have a ratio of 2.5:3:1. Although this BCS was made specifically for the Houston toad, it may be possible to adapt it for use in other similar species of toads.
The authors wish to acknowledge the Houston Zoo, in particular the veterinary services department and conservation department. Special thanks to former Houston Zoo amphibian program manager, Paul Crump and lead Houston toad keeper, Tyler Parker.
1. Forstner MRJ, DJ McHenry, M Gaston, et al. The Houston toad 2007: annual summary of research and monitoring. United States Fish and Wildlife Service Report. Austin, TX. 2007:4–12.