杏吧原创

IN THE black depths of the night, a seal鈥檚 sensitive whiskers allow it to
catch fish it can鈥檛 see.

Seals and sea lions do not use sonar. Instead, Guido Dehnhardt and his
colleagues at the University of Bonn in Germany suspected that their whiskers,
which are well supplied with nerves, could help them to 鈥渟ee鈥� in the dark.

Sure enough, blindfolded harbour seals wearing earplugs could sense tiny
movements of water from a distance. They could not do this when muzzles impeded
their whiskers.

This explains why many blind but apparently well-nourished seals are observed
in the wild, the team says in this week鈥檚 Nature (vol 394, p 235).