Black lab puppy

Question
Actually I have two questions.  1. Our black lab puppy is 3 months old, and the older she gets, the hair on her back seems to be getting wavy, almost curly,  Have you ever seen that in a black lab?  She is a purebred, not a mix.
2.  We have an older dog that the puppy plays with all the time, but then when we go to play with her, she wants to bite just like she does with the other dog.  What can we do to stop her from biting us all the time when we play with her.  

Answer
Some pure bred Labs do have some wavy hair mostly at the back.  Some show a little feather on the legs too.  It may be a throw back to the Newfoundlands.  I have even seen a carefully bred one with long curly hair.  

Young Labs, which I know best, and other puppies tend to very bad about biting. You see a litter of them, and all the ones that are awake are biting another one or themselves. I am not even sure they realize that when they are alone, if they quit biting, they would quit being bitten. At 3 to 4 months they are getting their adult teeth, and it seems they spend every waking moment biting or chewing. One thing you can do at that stage is to knot and wet a piece of cloth. Then freeze it. The cooling will soothe the gums. Only let the puppy have it when you are there to watch it. I maintain a Lab's favorite chew toy is another Lab. Otherwise they settle for any person they can. They keep hoping to find one that won't yelp, jerk their hand away, and leave.

You just have to keep on correcting them, hundreds of times, not dozens. Provide sturdy, safe toys such as Kongs and Nylabones. Avoid things they can chew pieces off and choke on them. Keep them away from electrical cords. Crates are essential for most young Labs and other dogs.

The pet stores are full of toys that many dogs will quickly chew up into pieces they could choke on or cause intestinal blockages. If you are not there to watch, stick to sturdy stuff such as Nylabones and Kongs. Keep a close eye on chew toys and quickly discard anything that is coming apart in pieces. Rawhide is especially bad because it swells after being swallowed. I don't trust any of the consumable chews. The dogs just gnaw them down to a dangerous size too quickly. These problems are the worst with, but not limited to, large, aggressive chewers such as Labs.