Penguins, it seems, can't really taste their dinners. They aren't able to pick up on sweetness, bitterness, or a meaty flavor known as umami, a study finds. Instead, they can only taste sourness and saltiness, the BBC reports. That sets them apart from other birds, most of which lack the ability to taste sweetness but can still pick up on the other basic tastes. Teams of researchers made their findings in investigating penguin genomes; it would seem, says one scientist, that "umami and bitter tastes were lost in the common ancestor of all penguins," the Guardian reports.
Before you start pitying penguins, however, know that all this may not bother them much, since they swallow fish whole, researchers note. Still, it came as a surprise: "Penguins eat fish, so you would guess that they need the umami receptor genes, but for some reason they don’t have them," researcher Jianzhi Zhang says in a statement, via Time. It's possible that the weather has something to do with it: In cold temperatures, sweet, umami, and bitter tastes become hard to detect. Perhaps, then, penguins should just start wearing sweaters. (Why are some seals having sex with penguins?)