Study reveals big game animals must learn to migrate and pass knowledge across generations
September 6, 2018, U. of Wyoming
A team of scientists at the University of Wyoming has provided the first empirical evidence that ungulates (hooved mammals) must learn where and when to migrate, and that they maintain their seasonal migrations by passing cultural knowledge across generations.
Migration corridors depend on maintaining both habitat connectivity and animals' knowledge of the landscape, demonstrated by these migrating bighorn sheep in Park County, Wyo. Credit: Travis Zaffarano Trailcam Photo, Wyoming Migration Initiative
The results were reported today in Science.
Biologists have long suspected that, unlike many bird, fish and insect migrations that are driven by genetics, ungulates learn to migrate from their mothers or other animals in the herd. Previous research had hinted that migration was socially learned in ungulates, but a clear test had eluded researchers until now.
The authors of the study made use of a grand experiment that has been occurring across the American West over the last 60 years. After hunting and disease triggered the loss of bighorn sheep across much of their range, a cadre of dedicated wildlife managers, hunters and conservationists pioneered translocation programs to re-establish lost herds. Bighorn sheep from the few populations that persisted continued to migrate; some of these animals were captured and released into landscapes where bighorn sheep occurred previously. The conservation effort has been successful in establishing many new "translocated" herds.
University of Wyoming researchers Matt Kauffman, at right, and Kevin Monteith release a cow moose during a GPS collar migration study near Daniel, Wyo. Research has found that animals learn to migrate over several generations and pass that knowledge to other members of their herd. Credit: Mark Gocke
"The pattern was striking," says lead author Brett Jesmer, a doctoral student at UW. "Detailed GPS data revealed that fewer than 9 percent of translocated animals migrated, but 65 to 100 percent of animals migrated in herds that had never been lost."
Translocated animals did not migrate because they were unfamiliar with their new habitats, supporting the notion that migration requires extended periods for animals to explore, learn the location of nutritious food and pass that information on to other herd members, including their offspring. When migration and other socially learned behaviors are passed from generation to generation, these behaviors are considered to be part of an animal's culture, much like cultural knowledge shared within human societies.
The researchers also were interested in how long it would take for animals to learn to migrate. In recent years, ecologists have learned that ungulates migrate to "surf green waves" of nutritious food, coordinating their movements to graze on plants sprouting along mountain slopes. Much as surfers coordinate their movements to ride ocean waves, spring migration allows ungulates to "catch the wave" of young, nutritious plants that sprout at higher and higher elevation through the spring. This gives them more time to graze on the highest-quality food, helping them to survive and reproduce. For some ungulates, green-wave surfing is highly coordinated across vast landscapes, lasting weeks or months.
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