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20 IGUANA  •  VOLUME 15, NUMBER 1  •  MARCH 2008 LOCK

Detail of the external appearance of one hide area constructed for Guatemalan Beaded Lizards (Heloderma horridum charlesbogerti) at
Zoo Atlanta. The plastic tube connects to the deep shelter surrounded by flat stones.



In the ongoing effort to reproduce potential founder animals
at Zoo Atlanta, we have recently modified an outdoor enclo-

sure to hold our Guatemalan Beaded Lizards (Heloderma hor-
ridum charlesbogerti). The captive reproduction of these speci-
mens is an important part of the overall “Project Heloderma”
program for Zoo Atlanta and its partners, the International
Reptile Conservation Foundation and Zootropic. Our lone
female and our three males were wild-caught adults when
brought into captivity and are of unknown ages. Thus, with
every year that goes by, they get that much closer to being non-

reproductive. In addition, the female has had two surgeries to
remove cystic (fluid filled, non-viable) follicles from her ovaries.
The good news is that prior to the surgeries that removed the
diseased follicles she had not produced any eggs — but has since
ovulated successfully. In 2005, she produced six yellow, non-cal-
cified, and non-viable eggs, and, in 2006, she produced four
similar eggs.

To no one’s surprise, when the lizards were placed outside
in the sun, their behavior changed to more closely reflect that of
their wild counterparts. With that information, all five animals

The Guatemalan Beaded Lizard 
Breeding Program at Zoo Atlanta

Brad Lock

Zoo Atlanta

Photographs by Jason Brock, Zoo Atlanta

IGUANA  •  VOLUME 15, NUMBER 1  •  MARCH 2008 21GUATEMALAN BEADED LIZARD

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Outdoor habitat for Guatemalan Beaded Lizards (Heloderma horridum charlesbogerti) at Zoo Atlanta.



were placed outside this past June. The enclosure and the hide
areas were designed to “resemble” some of the structures we had
seen in their native habitat in Guatemala. The hide areas were

dug into the ground so that a cool, dark, humid environment
was created. Logs and grasses were placed in the enclosure for
security and to provide climbing structures. After a very short

22 IGUANA  •  VOLUME 15, NUMBER 1  •  MARCH 2008 LOCK

Male Guatemalan Beaded Lizard taking advantage of a sunny patch
for basking on a cool morning.

The outdoor Guatemalan Beaded Lizard enclosure showing the hide areas and logs used for climbing.



IGUANA  •  VOLUME 15, NUMBER 1  •  MARCH 2008 23GUATEMALAN BEADED LIZARD

(2–3 day) exploration period, during which the lizards were con-
stantly on the move, tongue-flicking every inch of the enclosure
and the structures within it, they settled into a routine. This rou-
tine, however, was much different than the behaviors observed
in their indoor enclosures. Inside, lizards moved very infre-
quently and were very docile in interactions with the staff.
Outside, they would lie at the entrances to their hide areas until
the sun struck the enclosure, and then they would bask for a few
hours, especially on cool mornings. If a person entered the
enclosure when a lizard was out exploring, that animal would
“run” very quickly to a shelter and “dive in.” In addition, if the
entrance to a hide was blocked, the animal would rear up and
give an open-mouthed hiss.

All of these new behaviors were great! In September the
males began to fight, and were observed copulating with the
female. Soon, she was evidently gravid and ultrasound revealed
large follicles, but without the extra fluid usually seen in her
coelomic cavity. In the previous two years, when she had large
follicles or eggs present, she retained a large amount of fluid
along with them. This time, however, she did not. An ultra-
sound a few weeks later revealed six shelled eggs. Over a four-
week period in late September and November, she laid six eggs,
and four appeared viable. Those four were very white in color
and had nicely calcified shells. Unfortunately, none of the eggs
had the blood spot that is present within a day or two and sig-

nifies viability. Over the next three to four weeks, no develop-
ment was observed and the eggs contracted.

During the upcoming breeding season, we will place all of
the animals in outdoor enclosures in the early spring and leave
them there until fall. We are very excited that this year will be
the year during which the first fertile eggs are produced in cap-
tivity. Stay tuned.Detail of the hide area. They are dug into the ground to provide a cool,

humid, and dark shelter.

Guatemalan Beaded Lizards have relatively small eggs. This is an egg
from 2007 that is the normal white color with a nicely calcified shell.




