Visual Signals

Sounds

Droppings and urine probably contain information on an individual's identity and perhaps its sex, and food remains simply say 'I've been here', but the most important information carrier is scent. This is a dark substance that is produced by the glands around the anus and genitals. These 'perfume factories' are engaged in full-time production of strong-smelling scent. Scent conveys information on the sex of the depositor, its age, how long ago it left the area and, if it is a female, whether it is in oestrus and ready to mate, and also the extent of male rivalry. Every individual has an odour print specific to itself and so the scent deposit also functions as an identity card.

Receiving an olfactory message requires a mere sniff, but leaving a message is rather more involved and is perhaps the most energetic of giant panda activities. n giant panda will deposit scent on the ground, a tree stump or log by squatting and rubbing its anal gland on the surface, using its bushy tail as a paint brush. Pandas will also scent-mark taller objects such as trees, particularly conifers, which have rough barks that perhaps allow scent to adhere better and last longer. To scent-mark a tree, a panda will either squirt urine onto it or rub scent from its anogenital glandular area. It does this by backing up onto the tree and raising its tail. A panda rarely does both actions –urination and rubbing in any one session but it usually combines either with trunk clawing. While marking, the depositor may shake his head or bob it up and down.

On occasion, a panda will leave its message at a greater height to increase the dispersal area of the scent. To do this, it will either its leg against the tree or, more rarely, do a handstand. Despite its size and bulk, it manages this by backing up against the tree and 'walking' up the trunk with its hind legs. Frequently marked conifers are easy to spot. An observer's eyes are drawn to a dark, smooth area where the scent and urine have been applied and, above that, an area lightly scoured by claws. This visual part of the signal is useful because it lasts longer than the scent deposit, which in turn lasts longer than the urine signal. The researchers could smell this urine from about 5 m (16 ft). It is especially musky, unlike normal urine, and it may contain, in males, a secretion from internal glandular tissue around the tubes that lead from the testes. Giant pandas do not leave droppings at scent posts. A giant panda defaecates at rest sites and wherever it happens to be at the time.