Bar­na­cles re­veal whale mi­gra­tion routes

BBC Wildlife Magazine - - Wild News -

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

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