Chimpanzees and bonobos are equally humanity's closest living relatives. As such, they are among the largest-brained and most intelligent primates: they use a variety of sophisticated tools and construct elaborate sleeping nests each night from branches and foliage. Their learning abilities have been extensively studied. There may even be distinctive cultures within populations. Field studies of "Pan troglodytes" were pioneered by primatologist Jane Goodall. Both "Pan" species are considered to be endangered as human activities have caused severe declines in the populations and ranges of both species. Threats to wild panina populations include poaching, habitat destruction, and the illegal pet trade. Several conservation and rehabilitation organisations are dedicated to the survival of "Pan" species in the wild.