Giant pandas are considered “living fossils” and relict species in the animal kingdom. But what do these terms mean? Certain species in nature have no close relatives found today, but similar forms can be identified in fossils. Such species have undergone little to no morphological change since their earliest independent ancestors evolved. The evolutionary process of these species, as evidenced by fossils, shows a straight line with no branches or significant interruptions. From the perspective of species origin and evolution, these species can be termed “living fossils.”
The term “relict” refers to something that is singular. If a species was once widely distributed and abundant throughout history but has drastically reduced in numbers and habitat size in modern times, it is classified as a “relict species.”
In summary, all relict species are “living fossils,” but not all “living fossils” are relict species.
Current research indicates that the ancestors of giant pandas, known as Ailuropoda, diverged from a common ancestor with bears about 8 million years ago. Since then, giant pandas have evolved separately, transitioning through several forms, including the small panda, Wuling mountain panda, and Bashan panda, leading to the modern giant panda (Evolution History of Giant Panda). The appearance and body shape of giant pandas have remained largely unchanged over time, allowing us to imagine what their ancestors looked like.
In terms of timelines, Ailuropoda appeared during the late Miocene and early Pliocene epochs, the small panda emerged in the early Pleistocene, the Wuling mountain panda appeared in the early to mid-Pleistocene, and the Bashan panda existed in the mid to late Pleistocene and early Holocene. Modern giant pandas emerged in the early Holocene, and their evolutionary process has been nearly uninterrupted, qualifying them as “living fossils.”
Archaeological evidence shows that giant pandas once inhabited regions throughout southwest, northwest, south-central, north, and even outside of China, such as Myanmar. Today, however, their range has been drastically reduced to parts of Sichuan, Shaanxi, and Gansu, fitting the definition of a relict species.