How is the Population of Giant Pandas Determined?

How Is The Population Of Giant Pandas Determined

Giant pandas, a “national treasure” unique to China, have their population and distribution closely monitored to ensure their conservation. Since the 1970s, China has been organizing nationwide surveys to assess the number of giant pandas in the wild, their habitat area, and their living conditions.

These surveys are typically conducted every 10 years and have been carried out four times so far. To ensure the accuracy of the data, Chinese researchers have employed various methods over the years.

Initial surveys were conducted between 1974 and 1977 and again in 1988. During these surveys, researchers selected specific areas as the survey range and followed certain routes within these areas to search for giant pandas. They estimated the number of pandas in the region based on the number found and the area covered, using mathematical formulas to infer the situation across the entire reserve. However, wild giant pandas are highly alert and can detect human and dog scents from a distance, often hiding before researchers get close. Due to safety concerns, the observation distance could not be too close, which led to lower accuracy in the results.

As research experience and technology improved, so did the methods used. From the third survey in 1999 onwards, researchers began combining the “distance differentiation method” and the “bite mark differentiation method.” These methods involve studying various signs left by giant pandas, such as feces, urine, hair, nests, claw marks, and footprints. After observing and recording these signs, researchers use computer analysis to determine the distance between two marks. If the distance between two points exceeds the normal activity range of a single giant panda, it is preliminarily judged that more than one panda is present in the area.

Giant pandas’ territories can overlap, making it challenging to determine their exact population. When the distance between two signs is within the normal activity range of a giant panda, researchers use the “bite mark differentiation method” to assist in their studies. After eating bamboo, giant pandas excrete undigested bamboo stems, which researchers examine for bite marks. By analyzing the depth and width of these bite marks, they can infer whether they were made by the same panda, thus estimating the number of pandas. This method, known as the “bite mark differentiation method,” has limitations. For instance, during some seasons, pandas may only eat bamboo leaves, leaving no bite marks in their feces.

Therefore, in the fourth survey, which began in 2013, researchers continued using the “bite mark differentiation method” while also incorporating DNA testing. They extract DNA from the collected giant panda feces. Since individual giant pandas have unique DNA profiles, this method allows for more accurate population estimation. However, this method is complex and challenging because researchers must collect fresh, uncontaminated feces. The DNA in feces can only be effectively extracted from fresh samples as intestinal cells die and degrade over time after leaving the panda’s body, making it difficult to obtain usable DNA.