The mystery of the lazy panda uncovered
PHOTO CREDIT: World Wildlife Fund
Pandas: currently one of the many endangered species in the world. A bear looking mammal with black and white colors, they eat bamboo and most importantly, they are lazy. This may be what most people would think when when they think of pandas, but what about other aspects? Specifically, let's investigate why pandas are so lazy. After all, they have bodies similar to other bears, yet it seems all they do is eat and lie around.
What is it that gives you energy to move around, run or play any athletic sport? The answer would be food. Different foods give more nutrition than others; some more, some less. In the past, pandas were not merely herbivores eating bamboo. They were once carnivores, at least their ancestors were. This switch of diet had an effect on them due to the significant difference in the amount of nutrition that can be given from an energy dense piece of meat to a stalk of bamboo. According to journalist John McQuaid, “Giant pandas have the digestive system of a carnivore, yet the feeding habits of an herbivore. Yet even for herbivores, they are exceptionally lazy. The team of Chinese scientists, plus one from Scotland, meticulously analyzed the hourly behavior of three wild and five captive pandas. The pandas’ daily energy expenditure was only 38% of what would be expected for a land animal of their body mass,” Pandas spend much of their time lazing around, even in the wild. To get even deeper into a panda’s digestive system, an independent multimedia journalist specializing in science, technology, and the environment “found little diversity in the microorganisms that live in panda guts, and none of the cellulose-degrading bacteria typically seen in other plant-eaters. Instead, the pandas' guts were dominated by Escherichia, Shigella and Streptococcus bacteria, which are normally found in carnivores.” This is further evidence that not only were the digestive systems of pandas in the past carnivorous, they are now as well. It also explains why they get so little energy from the bamboo as their metabolism is so slow. However this does not explain why their diet has switched to an herbivorous one.
The switch from a carnivorous diet to eating bamboo is quite puzzling. “Why would they do that?” you might ask, and the answer currently needs more research. However, there was a discovery of a taste receptor gene had changed. In a PMC article, it is stated that, “[t]he giant panda has an interesting bamboo diet unlike the other species in the order of Carnivora. The umami taste receptor gene T1R1 has been identified as a pseudogene during its genome sequencing project and confirmed using a different giant panda sample. The estimated mutation time for this gene is about 4.2 Myr. Such mutation coincided with the giant panda's dietary change and also reinforced its herbivorous life style”. However, this change can only be considered a coincidence given the provided research. There is currently no concrete answer to exactly why pandas have decided to change their diet.
Though we know why pandas are lazy, how do pandas get by if they have such little amounts of energy? Well, one answer is quite simple. They save energy by minimizing their movements. According to Professor John Speakman, co-first author from the Aberdeen University, it is discovered that, “...they rest for more than half of the day and on average, only travelled at 20 metres an hour.” It is stated that these pandas with GPS loggers are wild pandas, meaning that they should move around more than those in captivity. But it is shown that does not seem to be the case as they still laze around in the day. How about looking on the inside of pandas to see even more of how they conserve their energy. According to James Gerkin, an editor of Huffington post, researchers have found, “[p]andas have smaller brains, livers and kidneys than other bears, requiring less energy to function. They also have lower levels of two thyroid hormones, meaning they have a slower metabolism than similarly-sized mammals.” In other words because of their metabolism, they won’t eat too much, and they can conserve energy because some specific organs are smaller than other bears.
The core of the pandas laziness lie within their diet. Due to their choice of food, they receive less energy than needed for more movements, and as such they conserve their energy throughout the entire day. There has been a discovery of a taste receptor gene having gone under a change coinciding with when the diet change happened, but whether that is the reason for the change is yet to be seen. Their lifestyle is truly enviable though, sleep, eat, sleep, eat, maybe take one step, sleep more. Unlike how humans work, work, work, work, work, eat and work and finally sleep before waking up and doing more work.
