why do pandas eat so much bamboo
If youБre a panda bear, thereБs one thing you do a lot: eat bamboo. These creatures actually spend up to 14 hours daily eating as much as 27 pounds of the plant. New research gives a clue as to why: They arenБt very good at digesting it. in the journal mBio shows that pandas have gut microbes more similar to carnivores and omnivores than vegetarians. In fact, the animals lack the types of bacteria known for breaking down cellulose, the component of plant cell walls that make leaves and plant material difficult for other omnivores, like humans, to break down. Pandas can digest only about 17 percent of what they consume, the scientists calculated. in these slideshows БThis result is unexpected and quite interesting, because it implies the giant pandaБs gut microbiota may not have well adapted to its unique diet and places pandas at an evolutionary dilemma,Б said study co-author Xiaoyan Pang, a researcher at Shanghai Jiao Tong University, in.
The study notes that the bears evolved from omnivorous ancestors but likely began to specialize in bamboo-chomping 7 million years ago. But in that time, they havenБt evolved to become efficient at breaking down cellulose. As a result, the pandaБs stomach and intestinal system are more similar to a carnivore than a vegetarian. б
БThe animals also do not have the genes for plant-digesting enzymes in their own genome,Б said lead author Zhihe Zhang, director of the Chengdu Research Base of Giant Panda Breeding in China.
This, he says, Бmay have increased their risk for extinction. Б That s a very good question indeed. James has covered a lot of the ground, here, but I should be able to throw out a few thoughts on the subject. In 2010, scientists in China found that pandas seem to have lost the ability to taste savoury flavours, like meat, due to an inactive gene in their DNA. Taste is important in telling us what we like to eat, so modern pandas may not like to eat meat, even if it is available. They will and do eat some of course, but occasional meat makes up a very, very small part of a panda s diet.
This gene stopped working around 4 million years ago, which is about the time a lot of other animals died out. If your food disappears, you re going to eat whatever is around, and bamboo was everywhere. Since switching to bamboo, pandas have evolved extremely strong jaws which allow them to grind their food really well, getting as much nutrition as possible when it s digested. They also have a sort of thumb, which helps them be a bit pickier about how they eat. They eat the leaves of the bamboo first, and only go for the harder stem centres later. The thumb allows them to manipulate the bamboo while they feed. Another group of scientists found that bamboo might produce a reward response in the panda s brain.
To explain what this means, think of how much most people like sugary and fatty foods. There s a simple explanation for this eating these foods leads us to produce a chemical called dopamine, which makes us feel good. Our brain then remembers that we felt good and encourages us to eat more of the feel-good food when it s available. It turns out that pandas don t produce dopamine properly and so don t have a normal feel-good reaction. Chemicals in bamboo might help pandas make more dopamine. In short, eating bamboo might make the panda s brain think that as far as food goes, bamboo is pretty fantastic.
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