This image of two sealions using their whiskers to touch was taken at the Albuquerque BioPark Zoo.
Are we watching a greeting, like a handshake, or is this an expression of affection?
While considering the animal behavior observed by these two creatures, I read some information about the sensitive whiskers on pinnipeds (seals, sea lions, and walruses); marine mammals with fins for feet:
Pinnipeds have prominent and sensitive facial whiskers that use a specialized network of muscles the way we use our hands. They rely on their sense of touch to guide them around their environment. Apparently, the follicles of each whisker connect to nerves that pick up tiny vibrations in the air or in water. Sea lions can use their whiskers to discriminate between different shapes and sizes, down to differences as small as half a centimeter.