Kissing Animals

The physiology of kissing
Kissing is a complex behavior that requires significant muscular coordination; a total of 34 facial muscles and 112 postural muscles are used during a kiss. The most important muscle involved is the orbicularis oris muscle, which is used to pucker the lips and informally known as the kissing muscle. In the case of the French kiss, the tongue is also an important part. Lips have many nerve endings so they are sensitive to touch and bite.