Barnacles reveal whale migration routes
Some of the world’s biggest whales migrate distances befitting their size, shuttling annually between the tropics and the poles. And new data, from an unlikely source, suggests that they have been following similar routes for hundreds of thousands of years.
“Hunting for fossil whale barnacles is easier than whales, and they provide a wealth of information waiting to be uncovered,” says Seth Finnegan of the University of California, Berkeley.
As whales travel the world, these crustacean hitchhikers absorb chemical signatures from the waters they pass through, depositing them in layers in their growing shells. Because each whale lineage supports its own type of barnacle,
the fossils’ hosts can be identified, and their ancient migration routes inferred.
“The signals we found in the fossil barnacles showed us quite clearly that ancient humpback and grey whales were undertaking journeys very similar to those that these whales make today,” says Finnegan’s colleague, Larry Taylor.
Humpbacks from Antarctica and Alaska were meeting near Panama 250,000 years ago, just as they do today. “It seems like the summer-breeding and winterfeeding migrations have been an integral part of the way of life of these whales for hundreds of thousands of years.” SB