Kinship recognition and grouping in hatchling green iguanas

Summary The research addressed two questions: (1) doIguana iguana hatchlings recognize their kin, and (2) what are the recognition mechanisms? Eggs were collected from wild and captive-raised females and hatched in semi-natural incubators. In the first experiment we used eggs from two females. One of the clutches was subdivided to be placed in different incubators. Immediately after emergence one of these hatchling groups was introduced into a 10 m x 10 m enclosure. At the same time we introduced hatchlings from another female. The remaining hatchling group was kept separate for 3 weeks and was then introduced into the same cage. Unrelated hatchlings separated from each other. Related but separated hatchlings grouped according to introduction date. In the second experiment we maintained eight kin groups in individual cages and two hatchlings per kin group in an additonal cage. Hatchlings from the mixed group showed no preference for their kin before physical contact with pure kin groups had occurred. After physical contact hatchling recognized their kin by feces smell. Body odor is likely to be also involved.