Do pandas eat meat?
Why is tiger’s diet different from the cow’s diet?
The answer is that their bodies are designed to digest different kinds of food.
Cows have complex stomach with rumen allowing them to effective digest grass. In the rumen, millions of tiny organism mainly bacteria facilitate breaking down plant fibres into simple sugar molecules. On the other hand, tiger’s stomach is pretty simple and it is designed to digest meat but not grass (no vege in my diet, please!). To put it this way, animals only eat food that they can digest.
Hi. I am a vegetarian!
However, pandas are very unique regarding anatomy of their digestive system and their diet. Giant pandas also known as Ailuropoda melanoleuca belong to the bear family. They are able to digest meat, just like other species from the same family. According to some recent studies, giant pandas became herbivores and completely switched their diet to bamboo for 2.4 million years ago. Interestingly, there are no changes in anatomy of their digestive tract and they are able to digest meat. In theory, pandas can eat meat but not grass.
What made pandas become vegetarian although their body are designed to be Carnivores?
In 2010, a group of scientist from Department of Ecology and Evolutionary Biology, University of Michigan discovered the reason behind panda’s diet. The study using genome mapping compared the genome of giant pandas to other Carnivores. They found that there is a mutation in T1R1 gene. The gene encodes for T1R1 protein which is umami taste receptor. The mutation turns T1R1 into a pseudo gene: a gene which is no longer expressed. As a result, pandas cannot taste umami taste of meat and gradually lost their interest in meat.
Although pandas are not interested in meat and bamboo has become their major diet for quite a long time, their digestive tract, in theory, is not able to digest plant fibre.
How can pandas eat something they cannot digest?
Shortly after the first study was done, another study on panda genome shed the light on the myth. The study revealed that panda’s ability to eat bamboo is due to their gut flora rather than their genetic composition because they do not have genes encoding for cellulose-degrading enzymes. The result is in accordance with another study by Fuwen Wei, an ecologist from the Institute of Zoology at the Chinese Academy of Sciences in Beijing. In this study DNA was extracted from panda’s stool samples and sequenced. Results from DNA sequencing showed that panda’s gut carries a high load of Clostridium bacteria which have enzymes to break cellulose into simpler sugars. These bacteria live in panda’s gut and provide “digestive aid”. With the help from Clostridium, pandas can live as vegetarian despite the fact that they have a carnivore’s digestive system.
To sum up, pandas do not like meat because meat is not tasty for them and these pickiest eaters thrive on bamboo thanks to the tiny digestive helpers in their gut.
Now, do you know why pandas which were born as carnivores but live on bamboo?
1. Li R, Fan W, Tian G, Zhu H, He L, et al. The sequence and de novo assembly of the giant panda genome. Nature. 2010;463:311–317.
2. Zhao H, Yang JR, Xu H, Zhang J. Pseudogenization of the umami taste receptor gene Tas1r1 in the giant panda coincided with its dietary switch to bamboo. Mol Biol Evol. 2010;27:2669–2673.
3. Lifeng Zhua ,QiWua , Jiayin Daia , Shanning Zhang, and Fuwen Wei. Evidence of cellulose metabolism by the giant panda gut microbiome. Proceedings of the National Acedamy of Sciences of the United States of America. 2011