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unpublished.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.