Eye of the /Tiger Green Anole

In that classic of American cinema, Rocky III, Rocky Balboa (Sylvester Stallone) employed a particularly cunning strategy during the climactic fight with the younger, stronger Clubber Lang (Mr. T): he used his face to repeatedly absorb all of Clubber’s most powerful blows until Clubber grew very tired. Rocky’s strategy worked, and Clubber, fatigued from what seemed like hours of savagely beating Rocky in the head, ultimately succumbed to one of the relatively few punches Rocky managed to land.

Repeat until World Champion

Now one might suspect that Rocky III’s inspiring message of never giving up being punched in the face would have few adherents in the animal world, and this is indeed what we find. In most cases of male-male combat, combatants are reluctant to enter into escalated physical altercations because the risk of injury to themselves is too high. Instead, males of many animal species have evolved ritualized aggressive signals or displays aimed at intimidating their opponents into withdrawing, and will turn to violence only as a last resort when all else has failed. But some species have adopted the spirit of Rocky’s strategy, if not the letter, and rely on persistence to outlast as opposed to outfight their opponents.

A new study by Wilczynski et al. shows that Anolis carolinensis (the undisputed greatest study organism in the world) may use persistence as part of its fighting strategy as well. Adult male green anoles establish dominance hierarchies initially through aggressive interactions, and the outcomes of these interactions are affected by a variety of behavioural, physiological and morphological factors, many of which are likely reflected in the pattern and intensity of their ritualized aggressive displays. Wilczynski et al. set up staged aggressive interactions between pairs of adult males in the laboratory and tested whether males that responded faster or for longer to behavioural challenges were more likely to win fights. They also noted the colour state, as well as the presence of post-orbital eyespots, of winners and losers, both of which have been the subject of previous discussion on Anole Annals. The authors found that for the measured types of display, future dominant individuals generally displayed more frequently, and continued to display for longer than future subordinate individuals, whereas the effects of latency to display on competitive outcomes is less clear. With regard to colour, despite some intriguing trends, there were no significant differences between dominants and subordinates in any aspect of post-orbital eyespot expression. However, future dominant individuals did remain bright green for longer throughout the interactions than did future subordinates, supporting earlier suggestions that dark brown colouration is linked to subordinate social status and/or stress.

While persistence is a key component of contest behaviour in many animal species, the apparent importance of persistence in display duration in particular is especially interesting within the context of lizard displays. For example, duration of sagittal compression has previously been suggested as a handicap display in Uta stansburiana lizards, and previous studies have also suggested that persistence, perhaps related to accumulation of metabolic costs (paper here), might also dictate male contest outcomes in green anoles. Despite the wealth of knowledge regarding male green anole displays, studies such as Wilcynski et al.’s show that we still have much to learn regarding the behavioural aspects of male combat in this species, not to mention the likely relationships between behaviour and physiology.

Rocky III was unjustly spurned by the Academy of Motion Picture Arts and Sciences in 1983, not even receiving a nomination in the category of best picture (Ghandi won that year for some reason). Even more outrageous, it didn’t win the Best Original Song category it was nominated in! (Would anyone seriously argue that “Up Where We Belong” is a better song than “Eye of the Tiger”? Because it isn’t, and you are wrong). In retrospect, the reason for this travesty is clear: persistence is an important part of animal fighting strategies, and Rocky III was actually a nature documentary.