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For us
humans, one of the greatest experiences is to taste all kinds of delicious
food. But for penguins, they cannot get a taste of this happiness. That's
because penguins can't actually taste the delicious flavors (味道) of their favorite food-fish!
Scientists
from the University of Michigan examined the genome (基因组)of five species of penguins. They
found that no one can taste umami (鲜味),the flavor of
meat or fish, the BBC reported.
Many
animals have five basic tastes: sweet, sour, salty, bitter and umami. But
according to genetic data, penguins are believed to have only sour and salty
tastes.
These
findings are surprising and puzzling. And scientists don't have a good
explanation for them. But they have a few ideas.
First, one
of the umami genes doesn't work in cold temperatures. "It's about zero
degrees when they eat cold fish," Zhang Jianzhi, the lead scientist, told
the Daily Mail, so even if the penguins had a functional (功能的)gene, it might not work when
they needed it.
Second, penguins'
tongues (舌头)
are very special which may have something to do with their lack of taste.
Instead of being covered with taste buds which help to taste food, penguins'
tongues are very spiky. This is better for them to hold slippery (滑的) fish than tasting them. One study even showed that some types of
penguins don't even have taste buds.
However,
penguins seem to be managing just fine.
"Their
behavior of swallowing food whole, and their tongue structure and function,
suggest that penguins need no taste perception," said Zhang.
