My dog is a Minpin-Dachshund cross, about 20cm tall at the shoulder. He has this behaviour that is really slowing down our walks - he often would like to stop every 2-3m or so.
While on leash as we stroll through the neighbourhood, he lowers his head to sniff the grass – usually 5-10cm high – along the sidewalk. Then, when he finds the "right spot", he moves a bit farther into the lawn, lowers the front legs while keeping the back ones extended so he can almost touch the ground with his nose and sometimes licks the grass – dangerous behaviour of course, in this era of heavy fertiliser and herbicide use.
Simultaneously, he uses the back feet to propel himself forward and, upon finding the next "right spot", turns his head left or right while lowering the back legs, and twists and wriggles his way though the grass for maybe 90cm with his paws in the air. Could there be a snake somewhere in his ancestry?
Usually when almost finished, especially during pollen season, he sneezes.
The possible reasons that occur to me: so the sneezes will clear his nasal passages; to scratch his back, although the grass doesn't seem stiff enough for that; to "correct" his scent; to lick up any moisture remaining on the blades of grass from dew or irrigation, although he does have the opportunity to drink his fill of fresh water just before and after every walk; for the fun of it.
What do you think?
– Bruce Manuel
Dear Bruce: Dogs do roll in the grass because it feels good, especially on hot days. The primary reason they do it, however, has to do with their ancestry, not as snakes but as wolves.
When a wolf comes across an unusual or different smell, it often will roll in it. Dogs do this, too. The reason is two-fold. One, by mixing a little of their scent on top of the new one, they're putting their mark on the spot. Secondly, they like to share the scent, so by rubbing it all over themselves, they can share it with the pack.
This might help the pack to survive, if the odor turns out to be from a predator. The wolves will recognise the scent and be on guard.
By grass-diving (I like your term), your dog may want to share the odour with you while simultaneously marking his territory.
Conversely, your dog might be trying to get rid of an unpleasant or displeasing scent on his body. We might prefer the smell of flowery shampoo over the scent of wet dog, but that doesn't mean your dog does. Unless you're bathing him before every walk, however, I'd say this isn't the reason.
Other possibilities could be that he has a rash and finds the grass soothing on irritated skin (be sure to check), or he just might have an obsession with rolling in the grass.
As for the licking, he's probably trying to get more of the smell, and the sneezing likely is caused by your dog being so happy with his backstrokes that he smiles, which tickles his nose.
There's a little risk with this behaviour. As you mentioned, some people put chemicals on their lawns. So if you limit the dives to trusted areas, it should be just fine. – Tribune News Service/The Mercury News/Joan Morris