Whilst hiking the other day with my usual gang, one of us spotted a saw scaled viper sitting (laying?) on a rock. This is the first snake I have seen in the wild here in the UAE.
Apparently, it can rub its scales together to make a hissing noise. The snake developed this ability to 'hiss' because hissing with its lungs would waste moisture so valuable in the desert.

It looks rather large...

... until you see it in relation to a person.
After a few flashes from our cameras, it had enough attention and slithered off into the rocks.