While adult pandas are usually solitary creatures, they do communicate periodically through scent marking and vocal calls. These vocalizations include as many as 11 different sounds.
While adult pandas are generally solitary creatures, they do occasionally meet. Whenever they do, they don't communicate in the same way as most other animals. This is because their faces can't display expressions, they don't have a mane, their ears are small and their tails are stubby. Due to these limitations, they can only communicate by scent marking or vocalization.
Pandas create scent marks through a dark, thick and sticky substance secreted from their anal glands. The panda rubs it onto tree trunks and rocks that are difficult to remove. The secretion announces that a panda is in heat or that this is his territory. Another panda is able to tell the gender, age, mood and reproductive status of the panda who left the scent marking. Much of this information is indicated by position that the panda leaving the mark held while creating it.
Vocal communication also occurs. Pandas have 11 different sounds. These include a barking sound (used to intimidate another panda), a goat-like bleating sound (during the reproductive season), honking, huffing, barking and growling. Cubs have also been known to make a whimpering sound.