Why do pandas eat bamboo
In the wild, the diet of the big panda (Ailuropoda melanoleuca) is almost entirely composed of bamboo. This is due to evolutionary processes: the pandas intestines are not designed to digest meat, while the animals' esophagus and stomach are lined with a thick layer of elastic mucous tissue to protect them from bamboo chips. And the “thumb” on the front paws is a modified sesamoid bone of the wrist and allows you to control even the thinnest bamboo shoots.
But this plant has a low nutritional value, and as a result, bears should eat from 10 to 40 kg of bamboo per day. But even this would not be enough for animals whose mass can reach 160 kg. Scientists suspected that with such a poor diet, pandas remain healthy due to low energy costs. Now this hypothesis has been proved.
An international group of biologists, including scientists from China and the UK, using GPS tags, studied the metabolic rate of pandas - both wild and captive. It turned out that the daily energy costs (EEA) of large pandas make up only 38% of the average of mammals with the same body weight. A 90-pound panda spends less than 50% of the energy a 90-pound person spends.
Wild pandas are more active than those that live in zoos, but their results (45%) are far from ordinary. On average, these animals rest for more than half a day, and move no further than 20 meters per hour. In fact, pandas spend even less energy than koalas sleeping almost all day.
The study of internal organs showed the brain, liver and kidneys of bamboo bears are much smaller than those of other members of the bear family, and thyroid hormones are at a minimum level - the same as in hibernating brown bears. This was made possible thanks to the mutation of the DUOX2 gene: in humans, its loss leads to decreased thyroid activity.
The results of a study published in the journal Science show that large pandas have evolutionarily adapted to bamboo food due to their minimal energy costs and hormonal background. However, this also brought a view to the brink of extinction: there are not so many safe bamboo thickets on the planet, every year there are less and less of them. In the zoos of the world these animals are fed with special “cookies” made from pressed bamboo fibers.Do you like the article?
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