People who have seen pandas in a zoo often have the following question – why are the pandas always sleeping when there’re visitors?
There are two reasons:
The first is that the rest time of wild giant pandas is not the same as human beings:
0: 00-2: 00 rest, 2: 00-7: 00 breakfast, 7: 00-10: 30 rest, 10:30-11:30 playing, 11: 00-12: 00 lunch, 12: 00-14:30 rest, 14: 30-21:00 dinner, 21: 00-22:00 rest at night.
The second reason is that pandas prefer cold weather than a hot one. When the weather is cool, pandas are more willing to go outdoors. When the outdoor temperature rises above 26 degrees, pandas naturally want to avoid the summer heat and would reduce their activities.
Pandas get very little amount of energy from the bamboo that they eat all day. Therefore, they need to save as much energy as possible. The scientists studied the amount of daily energy spent of 5 captive pandas and 3 wild pandas, and found that they consumed only 38% of the energy of a similar animal of the same weight. Pandas consume only slightly a bit more energy than the three-toed sloth, famous for its laziness.
Pandas in zoos are lazier than those in the wild. In captivity, pandas spend only 33% of their time being active. However, in the wild, they spend 49% of their time moving around. Scientists have tracked pandas with the Global Positioning System (GPS) and found that they are even less active than other bears. This tracking system is the same device used for satellite navigation, and it found out that pandas also move very slowly in the wild.
Pandas save a lot of energy needed for physical activity. In average, they only move 20 meters per hour, but their low activity could also help them to slow down metabolism. It’s worth noting that the metabolic rate of an active panda is still lower than that of a completely immobile person.
We’ve found that their low metabolic rate is often associated with very low levels of thyroid hormones. The low level of thyroid hormone in pandas is related to their unique way of synthesis of thyroid hormone.