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TODAY'S SCIENCE TRIVIA: At first glance, the giant panda (๐๐ช๐ญ๐ถ๐ณ๐ฐ๐ฑ๐ฐ๐ฅ๐ข ๐ฎ๐ฆ๐ญ๐ข๐ฏ๐ฐ๐ญ๐ฆ๐ถ๐ค๐ข) might seem like it's living the dream. This iconic Chinese bear spends about 10 to 16 hours looking for food and eating, and the rest of its day resting and not really moving around a lot. There's a lot more to this situation than it looks, though... and it has nothing to do with them being lazy.
Pandas eat so much bambooโanywhere between 20 and 40 pounds a dayโto sustain their nutritional requirements. That's because they're basically built like carnivores, at least as far as their stomachs and intestinal systems are concerned: They don't have the proper gut bacteria for breaking down cellulose, the carbohydrate that strengthens plants' leaves, stems, and branches. In fact, researchers estimate that pandas only digest about 17 percent of what they eat, meaning the rest of it goes straight from bamboo to "Bam, poo."
Now, you might be wondering: If a panda's guts can't handle shoots that well, then why won't it just go chomp on a steak instead?
Well, things weren't always this way for these black-and-white bamboo-eaters. Approximately 7 million years ago, ancient relatives of the giant panda were omnivorous; the shift in pandas' eating habits only started somewhere between 2.4 million and 2 million years ago. Pandas' jaws and teeth became more well-suited for crushing bamboo, and their wrist bones evolved for grasping bamboo stalks more efficiently. More importantly, the gene for the panda's umami taste receptor (which is what makes protein from meat so appetizing) just stopped working. Right now, though, it's a chicken and egg situation: We're still not completely sure whether pandas stopped lost the taste for meat because they stopped eating it, or if it's the other way around. Interestingly, pandas have also learned to go for specific bamboo varieties that contain more of the nutrients they need.
Far from being "evolutionary cul-de-sacs," pandas have actually adapted quite well to their less-than-ideal circumstances. They're not dead ends on the bear family tree, as some argue. On the contrary, they've managed to survive and succeed for millions of years, despite the cards being stacked against them.
