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58 IGUANA  •  VOLUME 12, NUMBER 1  •  MARCH 2005 IGUANA NEWSBRIEFS

Getting Rid of the 
Gasparilla Island Ctenosaurs: 

The Lizards Don’t Want to Leave

A news item in the Boca Beacon, the
Boca Grande (Gasparilla Island) weekly
newspaper, reported that reptile rescuers
Jamie and Mark Mitchell of Pinellas
County came to the island with about a
dozen volunteers in an attempt to round
up as many of the introduced Spiny-
tailed Iguanas (Ctenosaura similis) as they
could capture on 17–18 December and
attempt to domesticate them. The
Mitchell’s claimed to have screened 300
individuals who had applied to adopt the
captured animals and had a further
2,000 adoption applications. On both
days of the roundup, conditions were
partly cloudy and daytime highs were
around 70 °F. According to Sarah
Watkins, Director of the Gasparilla
Island Conservation and Improvement
Association, with whom the rescuers had
coordinated their efforts, the actual num-
ber of animals caught was “around six.”

As well-intentioned as I’m sure the
Mitchell’s were, a brief study of some
ctenosaur natural history might have
served to increase their chances of cap-
turing animals. These ctenosaurs are wily
ground-dwellers. On Gasparilla, they
have adapted to hiding (sometimes in
Gopher Tortoise burrows) on days when
temperatures are suboptimal. Each indi-
vidual, regardless of age or gender, will
usually occupy a clearly defined territory
capable of providing adequate food
resources, basking spots, lookout spots,
and a snug retreat into which it can
quickly escape at the first sign of danger.
In short, these animals are not easy to
catch even for professionals, much less a
random collection of volunteers.

A second, equally relevant issue is
the proposed plan to “domesticate” the
animals once they were captured. In my
experience with the captive care of six (of
17) different ctenosaur species, I would
say that Ctenosaura similis is among the
more difficult species to maintain. Some
ctenosaurs, notably C. acanthura and C.
pectinata, are social and well-adapted to
living in groups. Ctenosaura similis is not
the least bit social and individuals must

be housed separately. These animals also
are easily extremely wary and, if unable
to retreat into a secure spot, they can
become very aggressive, even to the point
of being self-destructive. In essence, they
make poor captives.

A number of years ago, I adopted six
Gasparilla ctenosaurs trapped by a local
rescuer. Even the very youngest of these
animals, little more than a hatchling, had
enormous difficulty adapting to captivity
and I have had a 50% mortality rate.

Perhaps, as Ray Ashton
(Commentary, p. 48) has suggested, this
is one instance when we simply cannot
correct the human folly that created the
situation, and the best response is to
stand back to observe and learn while
nature takes her course.

— AJ Gutman

An Endoscope and 
Iguana Burrows

The International Reptile Conservation
Foundation (IRCF) donated an endo-
scope with the intention that it be used
to probe iguana burrows during surveys
in the Dominican Republic (see
IGUANA 11(1):8–14). Ernst Rupp,
Grupo Jaragua, reports that they started
out by introducing the endoscope

directly into burrows. Unfortunately, the
tip of the endoscope gets clogged with
dirt and dust and visibility is quickly
reduced to zero. Maneuvering the cable
in the fairly wide burrows also was diffi-
cult. In an effort to avoid those problems,
they have experimented with inserting
the endoscope into various flexible plas-
tic hoses and tubes that can be maneu-
vered by pulling on one of two strings
that are attached to the distal end.
Flexible tubes seem to work best and
they feel that they are making some
progress.

They have experienced some success
inserting the endoscope into the burrows
of juvenile iguanas. Grupo Jaragua
recently acquired a digital camera that
can be attached to an adapter purchased
for the endoscope, so they hope to be
able to generate photographs in the near
future.

Unfortunately, the 3-meter cable of
the endoscope is not long enough to
reach the end of the burrows of adult
iguanas, which may be as long as 5 m.
Larger endoscopes are too expensive at
the moment and an additional problem
would arise in regard to the light source
(weight, batteries, power). In the interim,
they will continue to work on improving
their methods.

I G U A N A  N E W S B R I E F S

Ctenosaurs such as those established on Boca
Grande (Gasparilla Island) are quite elusive.
Photograph by John Binns.

An endoscope of the type used to explore
iguana burrows in the Dominican
Republic (note, however, that the scope
used in the field has a much longer opti-
cal cable than illustrated here).




