The culpeo fox chasing a guanaco. Photo by: Cristobal Briceño of WCS Chile.
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In a paper in Mammalia researchers from the Wildlife Conservation Society (WCS) announce the first observation of South America’s culpeo fox hunting young guanacos, a relative of llamas. In doing so the fox comes head-to-head with aggressive mothers defending their young: researchers were surprised to find the small 30 pound (14 kg) predator facing off a group of 260 pound (120 kg) adult guanacos.
The hunt provided new information not only about the diet—and audacity—of the culpeo fox, but also showed never-before-seen behavior from the guanaco. When attacked by the culpeo fox, researchers were surprised to see the guanacos move into defensive herds and not shy away from kicking and charging at the fox. Before this, guanacos were thought to have only one strategy against predation—flight. Whenever a guanaco is attacked by a puma, its other known predator, it flees rather than defends itself.
While the puma attacks guanacos with stealth and ambush, the culpeo fox chases young guanaco until they drop from exhaustion, a hunting strategy known as “cursorial predation”. The guanaco’s novel defensive response to the culpeo fox is probably due both to the fox’s smaller size and its hunting strategy, which makes flight a useless response.
As opportunistic predators, culpeo fox have been known to prey on lizards, rabbits, birds, rodents, and even sheep. But successfully hunting young guanaco—and surviving attacks from adults—awards this small wild canine new stature.
The observations were made on the island of Tierra del Fuego off the southern tip of South America. Perhaps significantly the island is free of pumas.
CITATION: Andres J. Novaro, Claudio A. Moraga, Cristobal Bricen, Martin C. Funes, Andrea Marino(2009) First records of culpeo (Lycalopex culpaeus) attacks and cooperative defense by guanacos (Lama guanicoe). Mammalia, Volume 73.