This isn't always the case. Neither I, nor my dogs were "thinking snake," when one of my dogs must have stuck her nose under a rock or in a hole. I never saw the snake. But I did see 2 puncture marks in her nose that were rapidly swelling. I knew immediately that she'd been nailed by a snake. She never made a sound when bitten, either! When I got her go the Vet, they said her blood work indicated either a prarie rattler or a diamond back. She got the anti-venim and is now fine. I've been hiking the hills for many years and generally know how to avoid snakes (keep my hands out of places I can't see, and careful when climbing over rocks or items with shady spots under them), but it can happen without warning and is always best not to think of oneself as immune. And I do think snakes are more aggressive during drought times. We've had more rain this year, and fewer problems. The only dead snake I've seen on the road was a bullsnake - and we like having those around. They keep away the rattlers. I've been hiking remote areas for decades, and used to see more snakes sunning on the rocks while I was on horseback (since they don't move for the sound(s) of horses). Last year was the first time I've had any experience with an actual bite. Just be aware that they are there, and take care.