March 25,
2019, University
of California - Berkeley
Barnacles
that hitch rides on the backs of humpback and gray whales not only record
details about the whales' yearly travels, they also retain this information
after they become fossilized, helping scientists reconstruct the migrations of
whale populations millions of years in the past, according to a new University
of California, Berkeley, study.
Oxygen
isotope ratios in barnacle shells change with ocean condition and allow
scientists to chart the migration of the host whale, for example to warmer
breeding grounds or colder feeding grounds. Now, marine paleobiologists led by
UC Berkeley doctoral student Larry Taylor have discovered that barnacles retain
this information even after they fall off the whale, sink to the ocean bottom,
and become fossils."
As a
result, the travels of fossilized barnacles can serve as a proxy for the
peregrinations of whales in the distant past, like GPS trackers from the
Pleistocene.
"One
of the more exciting things about the paper, in my mind, is that we find
evidence for migration in all of these ancient populations, from three
different sites and time periods, but also from both humpback and gray whale lineages,
indicating that these animals, which lived hundreds of thousands of years ago,
were all undertaking migrations similar in extent to those of modern-day
whales," Taylor said.
One
surprise finding is that the coast of Panama has been a meeting ground for
different subpopulations of humpback whales for at least 270,000 years and
still is today. Whales visit Panama from as far away as Antarctica and the Gulf
of Alaska.
This
information about ancient migration will help scientists understand how
migration patterns may have affected the evolution of whales over the past 3 to
5 million years, how these patterns changed with changing climate and help
predict how today's whales will adapt to the rapid climate change happening
today.
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