Scared dogs tend to growl nervous they shake and put there tails between there legs
They may put their ears down or put their tail between their legs
When a dog is scared, it normally drops it's ears, and tucks it's tail between it's legs.
According to the trainpetdog newsletter I received last 2 weeks ago, scared or nervous dogs tend to shake, bark, hide under the table/chair/bed and sometimes pee. When this happens, you need to comfort the dog or have it socialization trained.
Dogs will usually lower their head and pin their ears back and curl their tail between their legs.They will snarl and show their teeth and usually be in a "crouching" position accompanied by barking and sometimes drooling.