My parents dog bites my dog on the neck and shakes his head is this normal?

I have got a labrador which I take around to my parents place to play with there alaskan malamute, they seen to get on fine but have noticed that the alaskan malamute grabs my dog by the neck and shakes his head, I don't know if this is normal, my dog does not yelp or anything but it doesn't look good. Is this normal for them to play like that or have I got something to worry about. thanks