Reference for this article is:.- 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.

Hatchling gree iguanas show complex social behavior related to predator avoindance. Field observations on the anti-predator behavior of free-ranging individuals led to suppose the presence of some cooperative strategy, involving dimorphic sexual behaviors. Two set of experiments were designed: 1) comparing the exposition of both sexes to a model of a predator and 2) trying to asses whether they had differential mortality when facing natural predators. The first experiments showed that males performed more risky behaviors exposing themselves more to the model (Chi square p< 0.05). The second set of experiements showed that males were predated more often (Wilcoxon-signed-rank test, p<0.03). The higher exposition of the males to predators could be the proximate causation for the differencces in mortality. A possible ultimate explanation is that males, altruistically, expose themselves more to predators, benefiting related females. This is the first record of kin selection, other than parental care, reported in any reptil.