Unlike other animals, ungulates or hooved mammals know when and where to migrate from the knowledge that is being passed down from generation to generation.
Scientists have long suspected that ungulate migration is learned from their parents and other members of the herd, but this is the first time that it has been tested and proven in a study.
Sharing Knowledge To The Herd
To confirm that ungulate species pass down information from the older generation to younger animals, the researchers attached GPS trackers to bighorn sheep and moose. The findings were published in Science Magazine.
Since the 1800s, because of hunting and disease transmission from domestic sheep, the population of bighorn sheep declined steeply. However, in the 70s, wildlife officials began efforts to reestablish lost herds, moving bighorn sheeps from surviving population to areas they historically occupied. The translocation effort was a success and has established new herds.
Matthew Kauffman of the University of Wyoming and his team used this information for the experiment. The researchers tracked 129 bighorn sheep from an established population along with 80 bighorn sheep and 189 moose that have recently been moved.
They found that of the 80 translocated sheep, only seven that were integrated with pre-existing herd attempted to migrate.
"The pattern was striking," stated doctoral student and lead author Brett Jesmer. "Detailed GPS data revealed that fewer than nine percent of translocated animals migrated, but 65 to 100 percent of animals migrated in herds that had never been lost."
In North America, ungulates migrate from high-altitute to low-altitude breeding grounds during winter for food. Scientists call this "surfing the green wave" because hooved mammals follow the trail of new greenery to sustain them throughout the long journey.
However, translocated animals did not know this. They refused to move because they were unfamiliar to the new territory and, therefore, have no collective information to pass to the herd. They needed more time to explore their surroundings, learn to the surf the wave, and teach it to younger generations.
From Generation To Generation
The study also found that ungulate herds are more likely to migrate if they have mastered how to surf the green wave, but that takes a lot of practice that spans decades. For the reintroduced bighorn sheep herds, it took them 40 years to become accustomed to their new habitat and become 80 percent migratory.
"These results indicate that ungulates accumulate knowledge of their landscapes over time, and cultural transmission of this knowledge is necessary for migrations to arise and persist," added Jesmer.
The team hopes that their findings would encourage the conservation of migration corridors or the trail that ungulate herds traverse to migrate. If migration corridors disappear, the landscape becomes unfamiliar to the animals and they lose their collective information that tells they when and where to go to find food and survive.