Research on Green iguana, Iguana iguana

In 1988 I started my undergraduate research by studying the diet of green iguanas. In the interest of studying their diet without hurting or killing the animals, I caught  the animals in the field, climbing the trees where they lived or chasing them down when they were on the ground. I developed a method to studying their diet by performing a stomach wash to the animals and obtained the information of what they have eaten lately. Luckily the iguanas  do not chew the leaves or flowers  which allowed me to identify diet to the species level in most cases. My work was followed by one of my colleagues (Cesar Molina). Cesar and I caught a total of 365 animals of all sizes and identified 125 different items in the diet.

       I continued studying iguanas for five more years. I studied population dynamics, sex differences, tick infestations, predation, antipredator social behavior, nesting success, and farming . My experience with iguanas lead me to  fall in love for them and for all the secrets that they have on hold for us to uncover in the future.  For example one of the the most interesting results of our research is the finding that neonate iguanas have extremely complicated defensive mechanisms to avoid predation involving group-based strategies that may result in the voluntary sacrifice of some individuals for the benefit their sibblings.  In particular some males might attrack toward themselves the attention of predators buying, this way, their sisters the possibility to survive and reproduce.  Kin selection as well as the complicated dynamics of differntial survival, mating and reproduction of males and females seem to be involved in the explanation of this phenomenon; but the last words is still far from being said (click here to see the whole article).  I look forward have a little time to retake this line of research in the future.  Due to academic commitments most of this remains largely unpublished. Some of the articles that I have  managed to publish are listed bellow, the remaining are in the proccess of being published.

Some of the articles that we have published so far on iguana's biology are listed and linked bellow

-Rivas, J. A. and Levin, L.  Sex differential antipredator behavior in juvenile green iguanas, Iguana iguana: evidences for fraternal care. In: Evolution Behavioral Ecology and Conservation of Iguanas.  University of California Press.

.-Rivas J. A., Molina, C.R., and Avila, T.M. 1998.  Iguana iguana (Green iguana): Juvenile predation. Herpetological Review  29 (4): 238-239.

.-Rivas J. A., Molina C. R. Ávila T. M. 1996. A non-flushing stomach wash techniques for large lizards. Herpetol Review. 27(2): 72-73.

.-Rivas, J. A. and Ávila, T. M. 1996. Sex differences in hatchlings Iguana iguana. Copeia. 1996: 219-221.

.-Rivas, J. A. & L. E. Levin. 1995 Differential behavior in both sexes of green iguana (Iguana iguana). Journal of the International Iguana Society. 5: 15.