Lizard Pushups: The "Dear Enemy" phenomenon
You found that resident lizards were more aggressive toward strangers than neighbors. This is the "dear enemy" phenomenon, which has been observed in many animal species.
However, the benefit of this reduced aggression, and the exact way it works, is still under scrutiny. Some believe that a territory holder can save energy by reduced aggression against individuals that the territory-holder is familiar with. The territory-holder already knows about the abilities of the neighbor, and also knows that the neighbor is not likely to try to take over her territory, since the neighbor already has a territory.
This prediction requires that the lizard be able to recognize other lizards as individuals. Can they do this, and if so, how?
Martin Whiting of the University of the Witwatersrand, South Africa,
tried changing the color of the front legs of the lizard Platysaurus
broadleyi, and found that leg color did not seem to function as
a cue in individual recognition. P. Lopez and J. Martin, however, manipulated
odors in the lizard Podarcis
hispanica, and found that odor was
used as a recognition cue by these lizards.
Lizard territoriality and pushup displays:
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