Remarkable new film of wild pandas shows how the rare bears engage in some gymnastics to mark their territory.
Pandas can adopt four distinct postures to deposit scent, with probably the strangest being the handstand.
The bear goes upside down on its front paws with the aim of pushing its urine as high up a tree trunk as possible.
The amazing pictures were taken in the Quingling mountain range of north-west China, and will be shown on BBC One's Bears - Spy In The Woods programme.
It is said to be the first time wild pandas have been filmed in this activity.
The TV programme has been made for the corporation by independent wildlife filmaker John Downer. He pioneered a remote device called "boulder-cam" - a camera hidden inside a dummy rock.
The great advantage with remote cameras is that they are non-invasive. They are simple in design, often consisting of a stills camera in a protective housing.
From supermarket doors to panda photography
The trigger device is based on a pulse infra-red system, similar to the motion-sensing device that opens supermarket doors when you walk towards them.
The sensitivity can be adjusted to target animals of different sizes, ranging from pygmy shrews to bull elephants. When the camera is triggered, the animal produces its own self-portrait.
The equipment now comes in various guises - including the "bamboo-cam" used to film the pandas.
In the trash
Phil Dalton, the series producer on Spy In The Woods, told BBC Wildlife Magazine: "The fact that pandas need to conserve energy is clearly evident; all they seem to do is eat and sleep.
"Bursts of energy are avoided or reduced to an absolute minimum. Males are especially lazy and waste no effort on territorial defence or social interactions.
"They avoid energy sapping confrontations by scent marking, which maintains a physical distance between individuals.
Polar bears come in for a close shot
"Anal glands are rubbed on scenting posts throughout their range. Males even urinate against trees while doing handstands; the higher the pee the more dominant the signal.
"Such extraordinary behaviour is unique to the giant pandas."
The show follows the lives of several bear species. A "snowball-cam" is used to film polar bears. "Salmon-cam" is an underwater camera housed within a silicon salmon model, and is used to film surprising shots of brown bears hunting for food.
There is even a "trash-cam", an ingenious moving dustbin that captures North American black bears searching for junk food.
Bears - Spy In The Woods is broadcast on BBC One on Tuesday, 30 November, at 2100 GMT.