No, great apes do not have tailbones in the way that many other mammals do. Instead, they possess a vestigial structure known as the coccyx.
The coccyx is a small, triangular bone located at the base of the vertebral column. In many mammals, this structure is elongated into a tail, which is used for balance, communication, and other functions. However, in great apes—such as gorillas, chimpanzees, bonobos, and orangutans—the tail has evolved away due to changes in their locomotion and lifestyle.
As these primates adapted to life in trees and on the ground, the need for a tail diminished. Instead of a functional tail, they have a coccyx that serves little purpose in terms of mobility. This evolutionary change is a fascinating example of how species adapt to their environments over time.