Part of my grief over the loss of my little friend is due to the abrupt change in habit. Being able to be close to Pablo several times a day produced oxytocin in my brain - a neurotransmitter known to counteract stress. (No wonder pet therapy is a growing concern.) Oxytocin is most strongly produced between mother and child, but can appear in other loving exchanges. Pablo was a very touchy-feely feline - unlike other very sweet cats I have known over the years. How I miss his big, velvety paws!
Late last year, a series of fortunate accidents brought books on social isolation to my attention, including Loneliness, by John Cacioppo. One of the things he mentions in that book is something called "social snacking." In lieu of actual contact (a "meal") with a loved one, people e-mail, call, text, and gaze at photographs.
Today, I found this Guardian article on long-distance consolation. Seems just hearing the sound of your mother's voice can lower stress hormones (cortisol) and raise oxytocin!
The need for connection is so great, we evolved back-up measures. Reach out and touch somebody, indeed.