The Evolutionary Origins of Migrations

By Tudor Vieru on September 17th, 2010 13:22 GMT

According to a new scientific study, it would appear that even slight changes in the social behavior patterns of animals can eventually led to the appearance of massive migrations.

Experts say that the variations may arrange themselves in such a manner that they trigger a cascade of events that eventually leads to species beginning to migrate.

The researchers behind the new work found that the same held true for species that would have otherwise remained solitary.

Animal migrations have been known to occur since then dawn of time, and its since about the same time that people have been mystified about why they take place.

Bird, butterfly, whale, fish, and mammal species alike migrate at various times of the years, leaving from certain areas for extended periods of time, and then returning at a later time.

Caribou for instance moves across the Arctic planes, whereas other mammals migrate yearly over the Serengeti plains. Arctic Terns are the longest migratory animals, traveling an estimated 70,900 kilometers, or 44,300 miles, per year.

Over time, investigators have become well prepared to answer questions as to how migrations take place now, after millions of years since they first occurred.

But explaining how the first migration took place is a lot more difficult, regardless of the countless models science developed this far.

“Despite the ubiquity of collective migration, and the key function it plays in the ecology of many species, it is still unclear what role social interactions play in the evolution of migratory strategies,” say experts Iain Couzin and Vishwesha Guttal.

The two hold appointments as evolutionary biologists at the Princeton University, and are also the authors of a new study on the issue.

The work appears online, in the September 14 issue of the esteemed scientific journal Proceeding of the National Academy of Sciences (PNAS).

Interestingly enough, the two determined that while it may take only a few years for migration patterns to be disrupted, it takes centuries for them to recover.

Wildebeest migrating through the Serengeti could lose their ability to migrate within a century, but it will take many generations before the animals would pick up the habit again.

The work also showed that migrations largely occur because all species contain either “leaders” or “sociable” individuals, Wired reports.

The former category ignores other individuals and goes about following environmental cues, whereas the latter is oblivious to what nature shows them, but gladly follows others.

“Guttal and Couzin add evolutionary dynamics to the mix and set the scene for a new generation of experimental tests and applications,” add University of Sydney biologists Stephen Simpson and Gregory Sword, who were not a part of the work.
Migrations occur around the world, and countless species are engaged in such behavior
   Migrations occur around the world, and countless species are engaged in such behavior