Imag(in)ing a conservation breeding program for Guatemalan beaded lizards

Did you know that August 14 is World Lizard Day? While there are many lizard species at Zoo Atlanta worth celebrating every day, the story of one species is particularly noteworthy. If you’ve been following Zoo Atlanta on social media or in the news, you may remember a story from earlier this year about animals hatched at the Zoo traveling south of the border as part of a conservation breeding project. I’m referring to the Guatemalan beaded lizards that transferred to La Aurora Zoo in Guatemala. My colleague Robert previously shared about this in a Keeper Story from January, but as we continue our exploration of the role of veterinary care in conservation, I want to highlight those aspects of this project here. 

The Guatemalan beaded lizard is a fascinating and, in many ways, mysterious species. It was only described to the global scientific community in the 1980s, and by that time it was already considered rare in its limited range. Only a few individuals of this elusive species were collected from the wild for research purposes, and Guatemalan scientists have done a good deal of research on wild populations, but there’s still a lot of questions left to answer. While we can refer to a species’ closest relatives (in this case Gila monsters and other beaded lizards, collectively known as helodermatids) as a starting point, reptiles are a diverse group, and we can’t assume generalizations across taxa. 

Zoo Atlanta has been a partner of an in-situ project for Guatemalan beaded lizard (GBL) conservation since 2005. While veterinary sciences have supported many facets of this partnership, they have been nothing less than essential to breeding successes achieved here. If you didn’t know, Zoo Atlanta is one of only a handful of zoos outside of Guatemala to successfully breed Guatemalan beaded lizards. 

An obvious step in managing a breeding population is identifying which individuals are male and which are female. Unfortunately, this is notoriously difficult to accurately do via visual inspection of adult GBLs (a potential exception is males in reproductive condition). Instead, ultrasound imaging is the most accurate way to identify male and female GBLs, with an added bonus that it can be used any time of year (not just the breeding season). 

Ultrasound imaging can also be used to monitor how internal sex organs and other structures change throughout the reproductive cycle. Reproduction is a complex process that can be influenced by many factors. As it turns out, those internal changes are an important piece of the puzzle of GBL breeding. Using this information to identify ideal breeding timing has contributed to the team’s success. In the last 12 years, 40 GBLs have successfully hatched at Zoo Atlanta. 

Veterinary attention on the individual level has also played an important role in the program. The GBL population at Zoo Atlanta started with 11 individuals, of which seven were male and four were female. As you can imagine, it was essential that each individual have the opportunity to reproduce. Once again, ultrasound imaging provided valuable insight to make this possible. The team saw that one female’s follicles, which produce eggs, weren’t functioning properly. After surgical intervention, she went on to produce viable eggs and even the first hatchling at Zoo Atlanta! 

The next time you visit us, be sure to stop by Scaly Slimy Spectacular and look for the Guatemalan beaded lizards (and their metaphorical “cousins” the Gila monsters and black beaded lizards). In addition to their hopeful conservation story, they have some exceptionally cool physical adaptations and behavioral patterns. Maybe one day you can even visit the Motagua Valley in Guatemala and see some of their literal cousins in the wild! 

Sources:

• Beck, D. (2005). Biology of gila monsters and beaded lizards. University of California Press. 
• Carruth, W.C. (2015). The reproductive cycle of the Guatemalan beaded lizard, Heloderma charlesbogerti [Unpublished master’s thesis]. Georgia Southern University. 
• Lock, B. (2008). The Guatemalan beaded lizard breeding program at Zoo Atlanta. Iguana, 15(1), 21-23. https://journals.ku.edu/iguana/article/view/17747/16007 
• Lock, B.A., Sanchez, D.A., Alvarado, L., & Binns, J. (2010, October). “Project Heloderma”: An in-situ conservation program for the Guatemalan beaded lizard (Heloderma charlesbogerti). American Association of Zoo Veterinarians Conference, South Padre Island, TX, United States.  
• Zoo Atlanta. (n.d.). Guatemala beaded lizard. https://zooatlanta.org/animal/guatemalan-beaded-lizard/ 
• Zoo Atlanta. (2024, July 17). Lizards from Zoo Atlanta will help wild populations. https://zooatlanta.org/press-release/lizards-from-zoo-atlanta-will-help-wild-populations/ 

Sarah Hamilton
Interpretive Engagement Specialist