# Petting dogs...what is it about the leg jerking? **URL:** \ **Category:** Factual Questions\ **Created:** [March 7, 2003, 4:11pm UTC](https://boards.straightdope.com/t/petting-dogs-what-is-it-about-the-leg-jerking/159733 "2003-03-07T16:11:02Z")\ **Posts on this page:** 16\ **Page:** 1
**Author:** ![ivylass](https://avatars.discourse-cdn.com/v4/letter/i/9de053/32.png) [@ivylass](https://boards.straightdope.com/u/ivylass)\ **Post date:** [March 7, 2003, 4:11pm UTC](https://boards.straightdope.com/t/petting-dogs-what-is-it-about-the-leg-jerking/159733/1 "2003-03-07T16:11:02Z")
You’ve all seen it…you’re scratching or petting a dog near the forelegs, and their hind legs starts twitching uncontrollably. I’m assuming there’s some nerve connection…is this comparable to a human’s funny bone? Is there any evolutionary purpose to this? I’m sure it doesn’t hurt the dog. My husband was petting our dog, and she promptly buried her head in the couch cushion, closed her eyes, and let her hind leg jerk away. I just find this a very funny phenomenon, and I’d be happy for any insight into it. ---
**Author:** ![Incubus](https://avatars.discourse-cdn.com/v4/letter/i/c68b51/32.png) [@Incubus](https://boards.straightdope.com/u/Incubus)\ **Post date:** [March 7, 2003, 4:13pm UTC](https://boards.straightdope.com/t/petting-dogs-what-is-it-about-the-leg-jerking/159733/2 "2003-03-07T16:13:36Z")
Sometimes I see cats do this too. Or they start doing ‘nipping’ gestures with their mouth. I think it probably is caused by the dog associated an itch being relieved with leg motion “If I move my leg like this, the itch goes away.” who knows, maybe the dog isn’t smart enough to know its someone else doing the scracthing and not them. ---
**Author:** ![BottledBlondJeanie](https://avatars.discourse-cdn.com/v4/letter/b/0ea827/32.png) [@BottledBlondJeanie](https://boards.straightdope.com/u/BottledBlondJeanie)\ **Post date:** [March 7, 2003, 5:24pm UTC](https://boards.straightdope.com/t/petting-dogs-what-is-it-about-the-leg-jerking/159733/3 "2003-03-07T17:24:51Z")
I only have a bit of info to add. My dog has 2 distinctive ‘spots’ that make her back legs go… one is on her upper chest…near the breastbone. The other is essentially her belly button…God I hope it’s not cruel…she seems to enjoy it…and I do too. I always humm “start me up” when I do it to her… ---
**Author:** ![NurseCarmen](https://avatars.discourse-cdn.com/v4/letter/n/5daacb/32.png) [@NurseCarmen](https://boards.straightdope.com/u/NurseCarmen)\ **Post date:** [March 7, 2003, 5:25pm UTC](https://boards.straightdope.com/t/petting-dogs-what-is-it-about-the-leg-jerking/159733/4 "2003-03-07T17:25:44Z")
It’s the happy button, and you’ve hit it. ---
**Author:** ![Velma](https://avatars.discourse-cdn.com/v4/letter/v/85e7bf/32.png) [@Velma](https://boards.straightdope.com/u/Velma)\ **Post date:** [March 7, 2003, 5:47pm UTC](https://boards.straightdope.com/t/petting-dogs-what-is-it-about-the-leg-jerking/159733/5 "2003-03-07T17:47:51Z")
I can’t find the spot on my current dog, so not all of them do it. She does love to have her tummy scratched, though. My last dog would start up practically before you even touched him. He also did this thing where if I ran my nails down his spine, the skin on his back would all bunch up by his shoulders - it looked really weird. I would guess it’s just a reflex. ---
**Author:** ![Bearflag70](https://avatars.discourse-cdn.com/v4/letter/b/8e7dd6/32.png) [@Bearflag70](https://boards.straightdope.com/u/Bearflag70)\ **Post date:** [March 7, 2003, 6:08pm UTC](https://boards.straightdope.com/t/petting-dogs-what-is-it-about-the-leg-jerking/159733/6 "2003-03-07T18:08:12Z")
My brother made up a term for that action. Our family now calls it **ferumba** (fer-UM-ba). Examples: Look at that dog ferumba. When I scratch here, the dog will ferumba. That dog is ferumba-ing. ---
**Author:** ![bordelond](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bordelond/32/150_2.png) [@bordelond](https://boards.straightdope.com/u/bordelond)\ **Post date:** [March 7, 2003, 6:18pm UTC](https://boards.straightdope.com/t/petting-dogs-what-is-it-about-the-leg-jerking/159733/7 "2003-03-07T18:18:30Z")
Isn’t that just the canine analog of being tickled? I suppose if dogs could laugh, they would. **Velma** is correct – like humans, not all dogs are ticklish. ---
**Author:** ![elmwood](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/elmwood/32/3060_2.png) [@elmwood](https://boards.straightdope.com/u/elmwood)\ **Post date:** [March 8, 2003, 7:28am UTC](https://boards.straightdope.com/t/petting-dogs-what-is-it-about-the-leg-jerking/159733/8 "2003-03-08T07:28:14Z")
> [@](#): > > \*Originally posted by bordelond \* > \*\*Isn’t that just the canine analog of being tickled? I suppose if dogs could laugh, they would. \*\* Mine do, when I tickle them. Seriously. I’ve got two dogs. When I roll them on their backs, and tickle their bellies, they grin, and them make an irregular panting sound, that sounds like quick exhaled bursts. Both of them respond the same way. If I’m tickling one, the other will join in and start nudging away too! ---
**Author:** ![GuyMontag](https://avatars.discourse-cdn.com/v4/letter/g/ad7895/32.png) [@GuyMontag](https://boards.straightdope.com/u/GuyMontag)\ **Post date:** [March 8, 2003, 12:14pm UTC](https://boards.straightdope.com/t/petting-dogs-what-is-it-about-the-leg-jerking/159733/9 "2003-03-08T12:14:56Z")
Changing species–I’ve seen quite a few cats that seem to start involuntarily grooming themselves when you scratch a particular spot. Strangest thing. ---
**Author:** ![Another\_Primate](https://avatars.discourse-cdn.com/v4/letter/a/f19dbf/32.png) [@Another\_Primate](https://boards.straightdope.com/u/Another_Primate)\ **Post date:** [March 8, 2003, 12:21pm UTC](https://boards.straightdope.com/t/petting-dogs-what-is-it-about-the-leg-jerking/159733/10 "2003-03-08T12:21:03Z")
> [@](#): > > \*Originally posted by bordelond \* > **Isn’t that just the canine analog of being tickled? I suppose if dogs could laugh, they would.** When I’m tickled, my arm or leg moves to **stop the tickling**. But the dog’s leg just floats out there. So I don’t think that’s it. ---
**Author:** ![mnemosyne](https://avatars.discourse-cdn.com/v4/letter/m/c4cdca/32.png) [@mnemosyne](https://boards.straightdope.com/u/mnemosyne)\ **Post date:** [March 8, 2003, 4:12pm UTC](https://boards.straightdope.com/t/petting-dogs-what-is-it-about-the-leg-jerking/159733/11 "2003-03-08T16:12:02Z")
Ever have a REALLY good back scratch? One that makes you tremble? I know I have twitched (my arm, usually) when my SO gives me a good back scratch, especially near the shoulders. I think this is something like what dogs feel - it just feels so good, and motion is sort of involuntary during it. ---
**Author:** ![sugaree](https://avatars.discourse-cdn.com/v4/letter/s/cc9497/32.png) [@sugaree](https://boards.straightdope.com/u/sugaree)\ **Post date:** [March 8, 2003, 4:40pm UTC](https://boards.straightdope.com/t/petting-dogs-what-is-it-about-the-leg-jerking/159733/12 "2003-03-08T16:40:23Z")
> [@](#): > > \*Originally posted by Incubus \* > \*\*Sometimes I see cats do this too. Or they start doing ‘nipping’ gestures with their mouth. \*\* > [@](#): > > _Originally posted by GuyMontag_ > **Changing species–I’ve seen quite a few cats that seem to start involuntarily grooming themselves when you scratch a particular spot. Strangest thing.** Dogs have kick spots; cats have lick spots. I’ve never seen a kitty kick. I’m going to start looking for this. ---
**Author:** ![Rhum\_Runner](https://avatars.discourse-cdn.com/v4/letter/r/2bfe46/32.png) [@Rhum\_Runner](https://boards.straightdope.com/u/Rhum_Runner)\ **Post date:** [March 8, 2003, 6:30pm UTC](https://boards.straightdope.com/t/petting-dogs-what-is-it-about-the-leg-jerking/159733/13 "2003-03-08T18:30:19Z")
I have seen the same thing in horses. Usually up near the withers there is a spot that a little scrath will result in the horse twitching and/or stretching out his neck and curling his lips. They seem to enjoy it. Got to watch out for a horse’s leg kicking around though. ---
**Author:** ![ivylass](https://avatars.discourse-cdn.com/v4/letter/i/9de053/32.png) [@ivylass](https://boards.straightdope.com/u/ivylass)\ **Post date:** [March 9, 2003, 3:04am UTC](https://boards.straightdope.com/t/petting-dogs-what-is-it-about-the-leg-jerking/159733/14 "2003-03-09T03:04:08Z")
> [@](#): > > \*Originally posted by mnemosyne \* > \*\*Ever have a REALLY good back scratch? One that makes you tremble? I know I have twitched (my arm, usually) when my SO gives me a good back scratch, especially near the shoulders. I think this is something like what dogs feel - it just feels so good, and motion is sort of involuntary during it. \*\* I wonder if that has something to do with it. A dog will scratch that portion under their foreleg with their hind leg. Maybe someone else scratching there triggers the hind leg to twitch. ---
**Author:** ![civilize](https://avatars.discourse-cdn.com/v4/letter/c/9d8465/32.png) [@civilize](https://boards.straightdope.com/u/civilize)\ **Post date:** [March 9, 2003, 5:28am UTC](https://boards.straightdope.com/t/petting-dogs-what-is-it-about-the-leg-jerking/159733/15 "2003-03-09T05:28:47Z")
Find the nipple line it works every time. Dogs and bitches ---
**Author:** ![Texican](https://avatars.discourse-cdn.com/v4/letter/t/ebca7d/32.png) [@Texican](https://boards.straightdope.com/u/Texican)\ **Post date:** [March 9, 2003, 1:17pm UTC](https://boards.straightdope.com/t/petting-dogs-what-is-it-about-the-leg-jerking/159733/16 "2003-03-09T13:17:12Z")
“Dogs have kick spots; cats have lick spots. I’ve never seen a kitty kick. I’m going to start looking for this.” Cats have a kick spot too. One of my friends could get my cats’ hind legs to going, but I could never find the spot myself.