Turf war

Natural History, July-August, 2003 by Erin Espelie

Staking out the boundaries of your spread can be a heedless act: In a Gary Larson cartoon a man points out a chirping sparrow to his son--emphasizing that territorial behavior occurs only among "lower" animals--while he stands amid a maze of picket fences in suburbia. But the male mandarin fish (Synchiropus splendidus) is anything but heedless about asserting its property rights. Every evening for about fifteen minutes the largest males--a whopping two inches long--among them the two fish pictured, fight their ongoing turf wars.

Alone by day, the psychedelically patterned mandarins graze on minute crustaceans--copepods--in the Indo-Pacific Ocean, hardly bothering to notice one another. But when the Sun begins to set, the focus turns to sex, and the large alpha males conspicuously secure a two- or three-square-foot plot of coral rubble for courting. Some nights, a harem of females joins a successful male that leads them one by one to the surface to spawn.

Photographer Constantinos Petrinos found a meeting site for mandarins in the Lembeh Strait, off the northern tip of the island of Sulawesi, Indonesia. He watched the alpha males seen here erect their spiky dorsal fins--a characteristic display of dominance--and was astonished when the mandarin on the left sank its teeth into its rival's neck. "They swirled for a few seconds," Petrinos reported, "until the loser fled to seek new territory."