Jumping and Biting

[BeksGlanvill]

I have a 6mth German Shepherd and mostly all good.  Except she goes through periods during the day of demanding behaviour.  All of a sudden she starts jumping at me and biting.  The bites don't really hurt unless she nips a tender area.  It's like she's trying to communicate something and my lack of understanding makes her worse.  Ignoring her makes her worse and redirection is impossible.

I keep telling myself she'll grow out of it but I'm worried she won't and I need to stop this behaviour before it becomes a serious issue.

Any advice?

[Adrienne]

Hi there,

Welcome to the forums!

You are right to be concerned because we don't want dogs to repeatedly rehearse problematic behaviors considering that the more they rehearse them, the more they establish, so we need to break the cycle and find ways to prevent this from happening. While it's true that some dog behaviors tend to decrease once puppies mature, some of them may stick around if there's some type of reinforcement fueling them. 

Now, I know of some very mouthy German shepherds who like to grab peoples' arms to conduct them someplace special. One of my clients has a stunning German shepherd named Quincy who would mouth his owner's wrist or hand to take him to the yard. He would only do this with very few people such as his owners, but he was very gentle in mouthing and owners found this endearing as it was as if he was grasping their hand to say "come with me and look what I found!" I am wondering if this is the type of behavior you may be seeing, only in a more insistent form and possibly from a dog who is feeling overstimulated or frustrated. 

In any case, it would be helpful to take a note of the behavior and determine the underlying cause so to tackle it accordingly. For example, at the very first sign of this behavior, you can see if walking towards the door that takes to the yard (if you have one) gets her to act happy as if you just understood her. If that's her case, you'll see her circling and maybe herding you to the door excitedly as if you just got it right. If that's the case, we may need to mostly refine her way to communicate, but at the same time evaluate why she may want to be in the yard with such impellent need in the first place ( does she need to potty? is there some critter outside? did she hear other dogs/people?).

I am a big fan of preventing behaviors we find problematic and tackling the underlying cause. So I would suggest paying very close attention when this behavior occurs. Can she be cranky and in dire need for a nap? Does it happen in the evening after a long day of her being awake? Many dogs don't get the really restful REM sleep they so importantly need. When dogs are cranky, they can be very bitey and have these episodes of crazy like behavior. I see this often in dogs who were rescued recently and have lots of stress hormones and a strong need to learn to relax.

Can she be having the zoomies? Many dogs get the zoomies (crazy running around) after meals and if they have no means for discharging this pent-up energy, they may try just go to jumping and nipping us humans in hopes of engaging us. 

Can she be anxious/overstimulated by something? Try to recall whether there were any sights or sounds (like from a window or from neighbors) that may have her worried and overstimulated.

What were you doing just prior to her acting that way? Can she be nervous or frustrated about something you were doing? Or maybe not doing (like walking past her bowl, but not filling it up? Walking by the door but not taking her out? 

If you can find a trigger, that can be super helpful as we are more in control of the situation versus a behavior that occurs randomly without any prediction and therefore happening for no detectable rhyme or reason. 

There are several things we can try to prevent this behavior if we find a pattern. If for example, it happens mostly in the evening when you are sitting down to watch TV, you can try taking her for a walk prior and making a new routine, that every time you sit down to watch TV, you provide her with a long-lasting chew (like a stuffed Kong) to enjoy for some time.  Let me know if you have noticed any particular patterns. 

 

[BeksGlanvill]

Thank you.  What you say makes a lot of sense.  When she was a young puppy she would get what I call poogressive, if she needed to potty.  I soon learnt her cue to go out.

It used to happen in the field on walks whether or not I was playing with her.  To combat it in the fields I've started making her sit or lay down before I throw her toy.  This has curbed 90% of this behaviour in the fields.

It mostly happens on an evening after she's eaten and whilst I'm trying to eat.  I've tried taking her for potty before and after meals but this doesn't help, she starts when back inside.  I've increased her fresh raw diet as she was refusing to eat any of her biscuits.  This behaviour often only lasts no more than 10minutes but they can be very intense.

Today it happened after lunch which she ate in the yard.  I managed to get her to calm down and started some of your training.  Take it/leave it she's brilliant at.  Target, not so good.  She knows what to do but if I ask her to do it more than once she starts jumping and panting.

Chew toys and Kong's only hold her attention a very short time.  She loves her bones but I have to limit how many she has.

This evening she again started after her food but instead of ignoring her and pushing her away, I tried a very different tactic and one I may come to regret.  When she jumped on me, I lifted her bottom up so she could sit on my lap, after a few minutes of gently mouthing my hand and chin she climbed off and went to sleep.  Whilst I ate my tea, she slept!

She gets three walks a day, with a nap late morning and occasionally mid afternoon.  Until recently she was napping a couple of hours mid morning and mid afternoon but I found she was awake and unsettled in the evening when napping too much in the afternoon so I now keep her awake a bit longer.  

During the night she is calm and happily self entertains when she wakes during the night and doesn't do any of her attention seeking behaviour, unless she needs to potty.  I'm with her 99% of the time but if I do need to leave her she's happy to be crated and will go to sleep or play with her toys till I get back.  I'm aware when she does it she reckons she's not getting the attention she wants but I have jobs to do and this makes her a bit stroppy!

 

 

[Adrienne]

Thanks for the extra details, they are very helpful!

At  6 months, she's entering the doggy adolescent stage, which is when we often witness some behavior changes, and among them, at this age, they have a deeper need for more exercise and mental stimulation. Often, we underestimate how much just tiring the brain can help during these trying times. So it's always a good idea adding some more mental stimulation (brain games) in those busy teenager minds. Here's a read about this stage:

https://www.braintraining4dogs.com/members/archive/survive-dogs-adolescent-stage/

It sounds like from your description, this behavior tends to happen the most during the evening. If the biting therefore seems to occur in the evening when your dog ate and you are trying to eat, it can help to preempt it. In other words, plan on creating a new routine that makes the behavior more unlikely. For instance, it could be that she's biting you because she has just finished her meal (a time when most dogs are energetic and often get those post-prandial zoomies), while you are sitting and eating and these idle times are boring her so she's seeking interaction. 

In such a case, it may help to feed her meal in a Kong (at the same time you are eating) so that she's working for her meal (which discharges some good amount of energy versus eating from a bowl in seconds) and on top of that, it gives you time to finish up your meal. I know you said Kongs don't keep her entertained for long enough, but have you ever tried feeding her meal in one and making it a little more enticing?

For example, if you are feeing her raw, you can stuff a piece of freeze-dried liver in the small opening of the Kong (the smell should entice her), then partially fill the Kong with raw meat or organ meats and then place the whole Kong in the freezer with the big hole facing up. Then, you can offer it to your dog simultaneously when your meal is ready. Offer it in an area that is easily washable and remember to clean up the Kong/floor surfaces as you would with anything you serve raw in to kill bacteria. The freezing makes for a more durable treat. 

If your dog is new to Kongs, you may need to take some steps to get her interested in them more. Like, you may need to place food in it that is valuable and easy to remove, before stuffing it in more challenging ways. You can start with some raw meat in it and then top with some peanut butter or plain Greek yogurt or some mashed banana before going to offering frozen meals. Once you are done eating and she is done too, you can see whether she is a bit calmer after working her meal out. 

There are many, many Kong stuffing recipes scattered throughout the web. Ask your vet what recipes you can try if you dog has any food allergies. 

Other ideas that come to mind:

-When the biting starts, walk out the room and close the door or stand behind a baby gate. Then, try to return after a minute, if she still tries to bite again, go out of the room again, always closing the door behind you. When she's calmer, return, and start offering her something to do such as a few fun training sessions and end it with access to a chew toy or bully stick to calm her down for some time.  

-Alternatively, right upon noticing the gleam in your dog’s eye, denoting that a nipping episode is about to start, be ready to start tossing some treats/kibble around to keep her nose and mouth busy in a more productive way. Make it a fun game. For ease of convenience carry the treats/kibble in a pocket or treat bag or keep some handy in several cups on several shelves around the home.

-Another option is to divert/re-direct with something super enticing. I know you said that re-direction is impossible, but often redirection is done with toys that are either too boring compared to interacting with us or that they see all the time on a daily basis. Have you ever tried redirecting to a real rabbit fur tug toy? I  have seen dogs go bonkers over it and loved to tug on it. The rules for a good game of tug is to "drop it" on request and never bite your hands. If an accidental nip occurs, say "whoops! game over" as you remove the toy and even leave. 

-Many owners of nippy pups enjoy redirecting to a flirt pole. This is like a fishing pole stick that has a stuffed animal at the end. Dogs love to chase it around as we move it in erratic ways. 

-Some dogs who love to chase things can be redirected by showing a ball and tossing it the opposite way. 

-This sounds like arousal/frustration biting, and it therefore helps to train our dogs some more impulse control. Impulse control isn't something that happens overnight, but as dogs start maturing and are trained. Here are several exercises:

https://www.braintraining4dogs.com/members/archive/impulse-control-frustration-tolerance/

-The fact that she is jumping and panting when you ask her to target, makes me thing she's struggling with the exercise because she doesn't understand it or is having issues with the training itself. Try not to show any frustration, make it a fun game. Watch your tone, don't make it sound demanding. Ask it once, then take a break, Then try again later to ask for another one. Then the next day, try asking a couple in a row. Praise her and reward her with something tasty. 

Finally, yes, sometimes they're just cranky and need to learn how to relax. I know you said that she has plenty of sleep, but we like to aim for at least 12 to 16 hours of sleep in a 24 hour period. So if she gets 8 hours a night, that leaves an extra 4 to 8 hours during the day. With some dogs, it's as if they just don't know when to stop and relax enough to catch some zzzs. It may therefore be helpful providing them with the right, calm environment to help them fall asleep and finally nap or at least relax with some calm activities (like several brain games). I always praise dogs (using a calm, soothing tone of voice) for showing calm, relaxed behaviors such as chewing on a toy, laying on a mat or just simply enjoying petting. They  don't happen very much when they are teenagers, so catch them when you can and praise them!

I hope this helps,

Let me know if you have any other questions,

Keep me posted on how things go,

Best,

Adrienne 

[BeksGlanvill]

Thanks for all your advice.  I've taken things right back to basics with Spirit and reinstated a two hour afternoon nap.  I've started to remove myself from her when she starts her demanding behaviour and her brain training has gone back to the beginning and I've broken it down into smaller bits.  All this seems to be working on her behaviour on an evening.  I'm doing a lot of work on helping her control her impulse behaviour.  She still has her outbursts, and has better days than others.  

On her time in the field she has reverted back to jumping and biting, even though she was doing so well.  I'm hoping that this is a final-ish kick back to authority as some days she's fantastic and other days she can't control herself.  When I'm able to get her to keep all four feet on the floor I quickly throw high reward treats on the floor.  I think it's all slowly working. 

One thing I am still struggling with is her over excitement at meeting people and other dogs.  When meeting people she can keep calm enough to sit on her bottom to say hi and get a treat from them or a petting but then she loses her composure.  With other dogs she just gets so excited that it doesn't matter what high reward food (pheasant, chicken or cheese) she's not interested.  All she wants to do is jump on them and if we're walking in front she is adamant she's not moving until they've caught up.  I live in the country so not a lot of opportunity to practice and socialising has been difficult with COVID restrictions.

Thanks for all your help

[Adrienne]

I hear you, this pandemic has certainly put a dent on all dog's socialization (and peoples' too). 

With her behavior around people, it sounds like she's doing fairly well overall. I know many young dogs who struggle a lot to even just sit so at least you have that part down. In this case though it seems like she needs to do something once she's done with the exercise. Here's the thing: when we have the dog sitting and then the dog gets a treat, once that treat is eaten, the dog thinks it's now OK to party as the exercise is over. It's sort of the end of the composure, so now we have a dog who not only still feels excited to be around people, but who is also wiggly and happy and celebrating being released from a sit. So we sort of get a dog in the mood for partying more than anything else.

Most dogs who struggle with staying calm when meeting people or dogs are young dogs who are excited, although in some cases, there may be a bit of overstimulation and anxiety too at play. It may help to keep things very brief and sweet, for example, you ask your dog to sit first, then your dog says briefly hi and gets a treat from the person and then you're back off to walking before she has the chance to behave inappropriately. When I have dogs in training, I just tell people that my dog is in training so we're just working on meeting people politely for a few seconds and then off we go back on our walks. 

This is because we want to prevent as much as possible rehearsing overly excited behaviors around people and we also want to lower the chance of people making our dogs too hyper with baby talks and petting dogs at the wrong time. Because, let's face it: many times the problem are the people our dogs encounter as they may pet the dog and fuss over the dog while the dog is jumping on them. Just the opposite of what we want to train! 

Then very gradually, we can try to increase duration of our meetings with people. Often, we'll need to give our dogs something else to do while we are chit-chatting with others. We can for example, keep a tug toy in our pocket and tug with the dog a bit or we can ask for several hand targets in a row and reward them, always cutting the conversation short to prevent going past our dog's ability to stay calm. We can also incorporate a stay into the initial sit, but even with that, we need to go very gradually. 

If we really want to work on this religiously, to ace it, we can enlist the help of some volunteer friends for this (we can even start with family members we casually meet on our walks). When training service dogs, we like to take turns in group classes acting as the people to greet and have strict guidelines to adhere to. For example, one of us approaches, the handler asks the dog to sit, we shake hands and the dog must stay in the sit/stay position. If the dog breaks the sit and tries to jump, the person being jumped on makes an abrupt about face and leaves to communicate to the dog that this way of greeting is not acceptable. Folks with good timing will be ready to leave the moment they even notice the dog's attempt to jump. We do several reps on this with different people and after some time, this feedback starts sinking in: basically, dogs start realizing that, if they hold the sit/stay they get a reward, if they break the sit/stay and jump, the person they so eagerly want to greet abruptly leaves.

The good news is that generally, as dogs mature, they will start getting less and less hyper around people. I have noticed this is more true with certain breeds such as German shepherds, Rottweilers and Dobermans. Around age 2-3, they become a little bit more aloof and this makes them much more manageable. Prior to that, it helps continuing their socialization, which right now, of course, isn't easy.

With my female Rottweiler who was Miss social butterfly when young and was always crazy to greet/meet people, I was able to tone down her behavior a lot with frequent trips to the city. Actually, we even enjoyed a 15 day long stay once in the city just to practice. After seeing so many people and dogs, and rewarding her for sticking to my side and doing several steps of attention heeling, she mellowed down considerably. She still acted a bit excited when she would spot a random person walking in the country, but she was much easier to control and never jumped. 

With other dogs, it sounds like she's too over threshold to consider eating. You can read about dog threshold levels here: https://www.braintraining4dogs.com/members/archive/threshold-levels/

You may have to skip close encounters for now (we don't want her to rehearse jumping on other dogs, which other dogs may not take nicely) until she's better under control. I would aim to practicing seeing other dogs from a distance and doing several steps of attention heeling. You can train this at home, then in the yard and then on walks at a distance from other dogs where she's under threshold. 

https://www.braintraining4dogs.com/members/brain-training/obedience-101/heeling-attention-heeling/

On top of increasing distance, another way to decrease threshold is by practicing often. Daily walks are important. Seeing dogs only every now and then increases their saliency. There is a phenomenon known as "suburban dog syndrome" which takes place in dogs who live in suburban areas and are reactive to seeing dogs and people because they are not frequent sights. If you walk your dog only on weekends things get more difficult. A daily walk, even if short (10-15 minutes) and just seeing one dog at a distance and her showing a bit of progress can suffix and you can call it a day.

And don't forget about exercise and mental stimulation (brain games!). If your dog is a ball of energy before walks, she will be much harder to control and over threshold. Drain a good part of her energy by playing games prior to the walk.

Expect some setbacks along the way; they are normal. When they happen, go back a few steps and work from a greater distance and decrease the level of difficulty. It is best if this exercise is initially done with calm dogs that do not create too much excitement. When you are at a point where your dog is responding well, you can try these focus exercises with dogs who are more on the hyper side. Remember that every time you are adding strong distractions, you should work from a greater distance since it is more difficult for the dog.

What to do if a dog is coming your way, but this dog is too close and you are afraid they'll send your dog over threshold? The Emergency u-turn may help in such cases:

https://www.braintraining4dogs.com/members/archive/emergency-u-turn/

Please note: If your dog is difficult to control on walks, you may find it helpful investing in a front-attachment harness (harness where the leash attaches to a clip in the middle of the dog's chest). Strong pullers may benefit from a head halter, but this requires an adjustment period and some dogs struggle wearing it. 

Once you she's much calmer upon spotting other dogs on walks, I would aim to walk her with some other calm dogs. Start with a friend with one calm dog. Parallel walking can help a lot dogs who need to learn to act calmer around other dogs. Parallel walks are just walks with other dog owners who have their dogs on leash and walk parallel to each other with the handlers in between to give distance. The dogs aren't allowed to interact. This is beneficial because it takes the pressure off the dog who doesn't have to focus on meeting/greeting/socializing/jumping and can focus on other things, but the group walk still gives them a sense of group adhesion, and it's still socialization although in a calmer, composed way. 

If you want your dog to play/interact with other dogs, make sure it's under a controlled setting (like off leash in a fenced area). In other words, if we let our dogs meet and interact with other dogs on walks, they'll come to expect that every single time they see a dog and this builds frustration those times we don't let them greet them. 

With the episode in the field, what happened exactly? Did she not listen your request to sit or lie down? Was she not interested in the toy? Is she on leash or off leash when this happens? It sounds like a case of zoomies. I like your approach of reinforcing her when she's not jumping.  Maybe we can make it a habit of playing some treasure hunt games when she's out there. https://www.braintraining4dogs.com/members/brain-training/elementary/the-treasure-hunt/

 

[BeksGlanvill]

Thank you.

I like the idea of parallel walking, I know a much older calmer dog, she's a good influence on my ball of energy.  I shall start telling my family to walk away as soon as she goes to jump/break sit.

As for walks, she gets a road walk morning and evening after walking through the fields playing frisbee.  On leash, I'm mostly super proud.  On the main country roads, she's told to heal and she's really good at it, she also knows to jump on the grass verge and wait if a vehicle approaches.  On the quieter back lane country roads I tell her to 'go wander' which means she can walk in front and stop and sniff whatever, which she's not allowed to do on the busier roads. Although if she pulls I either stop or make her walk in the opposite direction for a bit.  This is hit and miss how well it works, it often frustrates her in to jumping or biting the lead.  Food throwing helps but luckily she doesn't pull too hard on wander so we don't have a real issue.  She's usually just at the end of her leash, she likes to stop and sniff too much to pull ahead too far. Allowing her to go wander seems to help keep her attention and if need be I can call her back to heal quickly.  Our problem arises if we meet other people, which is often rare.  Then she's so excited all the excellent leash behaviour she can do goes completely out the window!

 

As for her jumping and biting during frisbee, I have no idea what causes it.  We can be playing frisbee and she'll be sitting before each throw and then suddenly she decides she doesn't want to sit, she wants to play tug with my arm, bum or coat.  Sometimes I see a change in her eyes before she goes and I can start throwing food and stop it happening but that is rare.  Sometimes she's half way to sitting and then decides jumping is better. It's like we have a battle of wills to see who's going to submit to the other.  It's like she says I've done what you've asked for a bit, now do what I want. Occasionally, she drains all my patience and understanding and I have put her leash back on and frog marched her back home but thankfully that is happening less. 

I know she'll get there and I remind myself she's still an energetic pup that sometimes just wants to play and get up to a little mischief and even though her best falls short at times, it's still her best and to praise her.

 

Thank you for all your help and advice.  I'm going to start reading the suggested articles to see what else we can work on.

 

[Adrienne]

 

You are very welcome. It sounds like she's doing overall well on the leash, she just needs to work more around distractions. If meeting people is rare on walks, that makes the presence of people extra salient, so this seems to interfere with her ability to stay composed. This whole pandemic situation is making things more challenging for many dog owners and it's starting to show up with dogs who are overly stimulated when they see people/other dogs (the other problem is separation anxiety after weeks/months of owners home). Hopefully, once this COVID19 thing is over, you'll have more opportunities to practice.

If you have people ever walking by your house and your dog can see them from a window, you can practice some look at that exercises (see link below). If you don't have any windows with people walking by, it can also help parking your car in a place where there are people walking by (from a distance where she's under threshold) and you can do some look at that exercises from there. Sit next to her, and when she sees a person, make a smacking sound and feed a tasty treat. Once you have a fast, almost reflexive response, this can work as a foundation exercise for the future attention heeling  exercise on walks around people/other dogs. 

https://www.braintraining4dogs.com/members/brain-training/university/look-at-that/

In general, I am not too fond in granting dogs off-leash privileges until they have proven excellent on-leash skills and a strong bond has formed with the owner. The reasons for this are several. One of them, is that once they savor the freedom of being off leash and sniff around, the moment we put the leash back on, it seems like dogs start  perceiving being on leash as punishment or at least they must feel stuck in some type of unpleasant situation-and we become a part of it. This happens mostly if we do so too early. 

On top of that, if we prevent them from accessing something they wish to sniff/greet/explore they may end up getting frustrated. Frustration may lead to leash biting and several displacement behaviors. A while back I had a dog over for board and training with the habit of eating his own poop (I know yuck, but this is rather common). This dog was often left for hours in the yard unattended and during this time, he would have fun eating his own stools. On my property, I decided to put a leash on him to prevent rehearsal of the troublesome behavior, and every time we passed by his poop with a short leash to start training, he was getting an itchy fit, in other words, he would sit down and would scratch. I noticed he would always scratch his collar as if manifesting his displeasure in wearing it and being prevented from doing what he did for years (eating poop). It's almost as if he had an "allergy to wearing his collar and leash."

The frustration started to subside once every time we passed by his stools, I would make my smacking sound and he was fed tasty chicken which he loved. Rep after rep, he would start looking at his poop and no longer pull, but would come closer to me to get his reward. At some point we progressed enough that he was able to still stick by my side even without the leash on. We then got to the point where he would poop at a distance, then he would happily come to me as if he wanted to show it to me where it was, I would clean it up with my pooper scooper and he would then get a reward for helping me find it. 

So if your stopping and walking the opposite direction is causing Spirit frustration and leash biting, if possible keep a note of when it happens (what triggered it? a person or dog?) and plan next time to work at a distance from such trigger (so she doesn't get too frustrated). From that distance, ask her to perform an alternate behavior to the pulling (attention heeling) which will set her up for success while also teaching her that great things happen when she sticks by your side. Also, make sure that once you turn, you can praise her and reward her after doing a few steps next to you so that she'll be less likely to feel frustrated. 

Creating a strong bond for leash walking is very important. As we walk with our dogs on leash, will inevitably compete against many, many temptations. If we become a strong source of trust, fun and rewards, we can potentially obtain a dog who chooses to stick by our side(when safe to do so,  even without the leash on) just because of all the great perks we offer. 

In beginner classes, I often enjoyed watching dog owners walk in a fenced area with the dog off leash. I monitored carefully how many times their dogs paid attention to their owners versus exploring the stimuli-rich fenced area. Often, dogs seemed to totally care less about them and were totally absorbed by their surroundings. Once on leash, there seemed to be a battle (dog wanting to explore, owners holding them back). After graduating from the leash 101 class, and re-doing the fenced area experiment, dogs would now stick always closely nearby, and even if they happened to explore, they voluntarily checked-in with their owners several times. 

If you have a fenced area, I would suggest rewarding any voluntary check-ins with your dog. Just every time your dog comes close to you despite all the temptation, hand feed a treat. This makes us interesting. It paves the path to a foundation of reinforcement.

Then, you can even start to practice what I call the "invisible leash exercise," where the dog voluntarily picks you over other things to sniff/explore because you have become the best thing out there. Here is a sample of this (please excuse the video quality, but it should give you an idea of what I am aiming for in different dog breeds). Initially, in the early stages the behavior tends to looks a bit sloppy (these were the first couple of days), but with practice, you start seeing more and more fluid responses. 

*Please note: when I toss a treat ahead sometimes, I do this on purpose to show what needs to be done when a dog happens to be ahead pulling; the dog needs to be drawn again into heel position, back into the reward zone. The German shepherd practiced this only on leash because he had growing pains and I couldn't allow any crazy romping around in our acreage if he decided to take off for some reason. 

 

Now, this doesn't mean we will always want our dogs attention heeling all the time. Attention heeling requires concentration and I use it mostly for when we're walking by triggers/ distractions. We can have them just walking next to us without pulling though and dogs need to sniff too every now and then, and we can grant this wish by putting sniffing on cue.  In other words, we can give them permission. We can therefore take our dogs to a spot and allow them to sniff around and then resume heeling once they start to lose interest in whatever they are sniffing. We can even attach a longer leash or a long line to help the dog discriminate between a shorter leash for heeling and a longer leash for sniffing/exploring. 

If the behavior in the fields is triggered when playing Frisbee, it could possibly be that 1) she is either getting tired of the game -when tired, games may even start to feel aversive and dogs may not know how to put it stop 2) she is getting too overstimulated/frustrated which can happen when play gets too out of hand, 3) she is looking for a different type of interaction.

I exclude the seeing who submits first possibility due to recent studies showing that dogs aren't trying to dominate us as we previously thought. Instead, dogs are more likely to do the things they do because of some history of reinforcement going on.  More on this here:

 https://www.braintraining4dogs.com/members/archive/dominance/

I used to have a foster dog who would not do this while playing fetch, but anytime she saw something that excited/overstimulated her and she didn't know how to cope with that. Impulse control and frustration tolerance games helped her learn to cope better with her overexcitement/frustration, and it also helped gradual exposure.  Brain games, relaxing mat games, clicker training, nosework helped a lot as well. She was no longer fed in bowls but worked for her every kibble, using it for training, brain games and for when she displayed calm behaviors. 

Lately, there has been a lot of discussion going on among dog trainers in regards to fetch. It's been described as an adrenaline-pumping activity with some dogs getting addicted to it due to its repetitive pattern. Other dogs instead just get too aroused. I like that you have a sit incorporated in it, but I would suggest watching when the biting behavior happens.

Is it after a while you have been playing? If so, maybe it may help to switch to another activity (how about playing tug with a long tug toy if she is very tug driven? Many GSD love tugging games -but make sure to train her to drop and that if she bites you during the game, you stop the game, turn around and even pretend to leave and resume once she's calmer) or just give a rest period with some calmer games (do a treasure hunt? bring along a bottle game, Lickimat? or how about a herding ball to move around?) to engage with in between. It may be therefore helpful to switch over before she gets to that point. It is easier to redirect a behavior before it happens than once it occurs. 

I hope this helps, happy holidays!

Best,

Adrienne

Disclaimer: Please note: frustration can spill into aggression. If your dog shows or has shown signs of acting aggressively at any time, please play it safe and consult with a force-free  dog behavior professional for safety and correct implementation of behavior modification.