They are known for aggressive displays of chest-beating, loud roaring and the occasional headlong charge.
But despite their macho reputation, gorillas are surprisingly delicate, especially when it comes to meal times.
Researchers have found that they use giant leaves as napkins to clean their fingers and faces after eating messy food.
The trackers, who were working for the Zoological Society of London in West Africa, witnessed several gorillas performing the same routine.
The finding is further evidence that gorillas and other great apes behave similarly to humans.
Dr Noelle Kumpel, the society's forests conservation programme manager, said: "We were amazed to discover that gorillas use these leaves like napkins.
"The team saw that the gorillas were wiping their mouths and hands after eating messy fruits. It's a surprisingly human activity. It clearly demonstrates that we still have plenty to learn about these incredible animals."
The apes tore giant leaves off a flowering plant to wipe themselves before throwing them to the ground.
The society's staff made the discovery while following a family of western lowland gorillas through the trees of a conservation park in Gabon. The trackers were trying to get the gorillas used to humans in the hope that it will draw ecotourism to the area.
Gorillas are actually far more gentle than their chimpanzee cousins and follow a vegetarian diet of leaves and fruit.
They also take some pride in their appearance. Grooming - where fleas, bugs and mud are picked from each other's hair - is an essential part of family life for gorillas.
Unlike chimpanzees, which routinely use tools such as twigs and stones to hunt and gather food - gorillas are less technologically minded.
They have, however, been seen using sticks to find their way across swamps and pools.
According to the most recent estimates, there are around 100,000 western lowland gorillas left in Africa. But logging, the spread of diseases such as ebola and the illegal trade in ape meat has seen numbers plummet. Some campaigners suspect there could be only 50,000 left.
Western lowland gorillas - one of the four sub-species of gorilla - usually live in family groups of between six and ten, led by a silverback, the fiercest and strongest male.
Once adolescent males are big enough they either challenge the silverback for leadership or leave home in search of a new family to lead.
Normally nomadic, gorillas use twigs and leaves to make overnight nests in trees or on the ground.