I have an innate need to touch things. It makes the object more real, more immediate. Seeing something is almost never enough for me to verify the existence of whatever it is I’m looking at.
I run my hands along fences and brush and buildings, especially if I’m in a new place. I like to know the heft of something and the textures and everything that makes up tactile sensation.
If I’m on a walk in the park, I’ll pick up pretty much every animal I see. Except copperheads. But I worry about the day when I see the opportunity to grab a copperhead, cause I know I’ll do it. Who would pass up an opportunity like that?
When I volunteered at the Carnivore Preservation Trust (now the Carolina Tiger Rescue), I would pet the tigers. And the ocelots. And the binturongs. Just with the flat of my hand across the fence, mind, not actually poking my hand into the cage. I might be stupid and reckless, but I am rather attached to my appendages. The tigers just wouldn’t be REAL otherwise, the memory less persistent, the experience more prone to fading.
By going to those extra lengths to touch something, memory becomes more nailed into place and I have less chance of losing it. It makes events stand out.
Plus, how many people can say they’ve touched a tiger?
Or a rhino for that matter.
(I can!)
Dylan Charles
dylancharles.net 
i think what your readers REALLY want to know is whether or not you feel a need to touch…people.
You sir, are horrifying.
I like your tag “Dylan is a bit odd.” I fully expect to see more under that one.