- Sounds
What the giant panda lacks in facial expressiveness it more than makes up for in an impressive repertoire of calls. These enhance the language of body posturing. There are about eleven distinct sounds that a giant panda emits, although there are gradations between most of them. Three of these, the huff, snort and chomp, are 'non-vocal', which means that they are not produced with the larynx; they are simply forcible expulsions of air modified by the animal's soft palate, throat and lips. By far the loudest and most intimidating of calls, to humans and pandas alike, is the roar. This call conveys aggressive threat at the highest level and is also used to locate the caller. It is a sound most often heard through the shifting mists of an April dawn when males are fervently seeking a mate. Both males and females will roar at each other from a distance and the sound is made to travel even further by calling out from the lofty heights of a tree. Females will also roar at courting males when they are not yet ready to mate and cannot be bothered by the males' persistent attentions. Roars are also emitted if two pandas quarrel during chance encounters. Another unambiguously aggressive call is the growl, which is not unlike that of a dog's. As with the roar, the growl is emitted by the more assertive e row individual and is often given with a moan.
The huff, snort and chomp are the calls of an apprehensive animal and are usually given in combination with the honk – for example, snort-honk, snort-chomp-honk, and huff-snort-chomp-honk. The huff and snort are more aggressive than the chomp, which is more a defensive call, uttered in anxiety. The chomp is also known as 'jaw-clapping' and is a repetitive sound consisting of a click, as the teeth are brought together, and a smack made partly by the animal vibrating its lips as it expels air through its mouth. Honking and, to a greater extent, squealing, convey distress and apprehension, a clear absence of aggressive intent. A sub-adult or low status panda will honk or squeal when threatened or attacked by an adult or higher status adult.
The other calls, the moan, bark and yip/chirp, signal increasing states of excitement. A panda may utter these in a variety of complex combinations and also with snorts, squeals and bleats. Their function depends on their context. In direct confrontations - for example, during courtship, when startled or when meeting casually – the moan, bark and yip may convey a mild warning against further interference and are essentially non-aggressive. Pandas also use the loud, audible moans and barks as long-distance calls, to advertise themselves, particularly in the mating season. The moan is a very variable call, ranging from a sharp hoot and softly repeated bu-bu-bu to a low-pitched moo, whiny groan, and long-drawn moan rising and falling in pitch, some, plaintive, others harsh. Facing another individual, a panda will sit or stand with lowered head and moans with mouth open or closed, or alternately open and close it. The chirp may also function as a social call during courtship and, with squeals, may also be used to draw attention to the caller.
The only call that lacks any aggressive or anxious undertones is the bleat. Sounding like the bleat of a goat, it is entirely friendly. It is a close-contact call uttered in the way of reassurance by courting and mating couples. The bleats of a panda are peculiar to that individual and so it probably works alongside smell to help individuals recognise one another.
One sound that is entirely confined to infant pandas is the squawk which can be short or long and drawn out. Young pandas make this sound when cold or uncomfortable and the more distressed they are the greater the pitch of the call.