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226 IGUANA  •  VOLUME 14, NUMBER 4  •  DECEMBER 2007 NIEVES

The Puerto Rican Ground Lizard (Ameiva exsul) is most frequently observed in relatively open areas actively rooting in leaf litter and soil. 



The Puerto Rican Ground Lizard, Ameiva exsul (Teiidae) is
the most widely distributed ground lizard on the Puerto

Rican Bank, which includes Puerto Rico, many satellite islands,
and the Virgin Islands (but excluding Saint Croix, Desecheo,
and islas Mona and Monito, which are on their own island
banks). Although mainly coastal in their distribution, these
lizards can be found at elevations >360 m above sea level in
Puerto Rico and have been observed at ~525 m on Sage
Mountain, Tortola, British Virgin Islands.

Male Puerto Rican Ground Lizards can exceed 20 cm in
snout-vent length; females are smaller. These lizards are strictly
diurnal and are most frequently observed in relatively open areas
actively rooting in leaf litter and soil, using their tongues to probe
for food. Puerto Rican Ground Lizards have a rather catholic
diet, and are known to eat many arthropods, snails, frogs, other
lizards and lizard eggs, as well as fungi, fruits, and even carrion.

The largest and most visible of the Virgin Island tarantulas
is the Ground Tarantula (Cyrthopholis bartholomaei). These spi-
ders build their nests in dry soil. With legs spread, they can span
10–13 cm.

Predation by a Puerto Rican Ground Lizard on a Ground
Tarantula occurred at exactly 1029 h on 14 October 2007 in leaf
litter associated with a rocky area along the road to the pier at
White Bay on Guana Island, British Virgin Islands. An adult
Ameiva exsul (SVL ~11 cm) was observed tongue-flicking what

I later identified as a tarantula burrow. Initially, the lizard
jumped back from the burrow, but it quickly reentered and
emerged with the tarantula grasped by its abdomen. The lizard
then proceeded to dismember and eat the spider. The entire
episode lasted about two minutes. Subsequently, the Ameiva
recommenced foraging.

Acknowledgements
I thank James Lazell of the Conservation Agency for providing
the opportunity to visit Guana Island and the Guana Island staff
for their support. Enrique Hernández and Neftalí Ríos,
Department of Biology, University of Puerto Rico at Humacao,
and Alejandro Sánchez provided valuable comments on an ear-
lier draft of this manuscript.

References
Cooper, W.E., Jr. 1990. Prey odor detection by teiid and lacertid lizards and

the relationship of prey odor detection to foraging mode in lizard fami-
lies. Copeia 1990:237–242.

Lazell, J. 2005. Island: Fact and Theory in Nature. University of California Press,
Berkeley.

Lewis, A.R. 1989. Diet selection and depression of prey abundance by an inten-
sively foraging lizard. Journal of Herpetology 23:164–170.

Rivero, J.A. 1998. Los anfibios y reptiles de Puerto Rico. The Amphibians and
Reptiles of Puerto Rico. 2nd ed. Editorial de la Universidad de Puerto Rico,
San Juan.

Predation on a Tarantula 
(Cyrtopholis bartholomaei) by a 

Puerto Rican Ground Lizard (Ameiva exsul)
Luis O. Nieves

Department of Biology, University of Puerto Rico at Humacao, Humacao, Puerto Rico 00791
Photographs by the author except where noted.

IGUANA  •  VOLUME 14, NUMBER 4  •  DECEMBER 2007 227PUERTO RICAN GROUND LIZARD

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A Puerto Rican Ground Lizard (Ameiva exsul) devours a Ground
Tarantula (Cyrtopholis bartholomei).

The Ground Tarantula (Cyrtopholis bartholomei) can grow quite large,
spanning as much as 10–13 cm.