Is it normal that my dog cries like a human

I have a catahoula dog that I love very much. Catahoulas are extremely caring, companionate dogs. They look for people to latch onto at a very young age and then stay by them thoroughly. Some think it is because of the Native American life style they evolved from. Eating, sleeping, hunting and working, always with their masters.

Anyway, my dog and I have always been close and he is always staring at my face and watching me do things. He also tries to grab me with his paws when he wants attention. Sometimes I get busy and ignore him for a while or even snap at him when he's being to clingy. He will the start crying. Like a full out human cry.

Sniffling, then whimpering. Not like a dog, like a human hiccuping when they cry. Then trembling and finally, actual tears rolling down his puppy face. I feel awful every time and hug him and he eventually calms down and hauls all 100lbs of himself on my lap while he sniffles and whines. He usually falls asleep after that.

Can dogs cry? Is he faking after years of seeing people cry? Are dogs smart enough to fake cry? He seems so sincere and I'm just baffled.