Male macaques also have very large canines, and massive jaw muscles to use them. A bite that severs a major blood vessel could end very badly.

They also move a lot more...three-dimensionally than you might imagine, making it hard to predict where they're going.

I've been looking through monkey bites, and they're a lot more tame on human skin than they are on other monkeys.

Macaques have large teeth and strong jaw muscles (as do dogs); but unlike dogs (or say even piranhas), it doesn't look like monkeys rip and tear flesh like canids. Their mouths are a lot like human mouths: incisors in the front, two canines on either side, and a bunch of (pre)molars, indicative of omnivores. The two canines will definitely pierce the skin. The incisors, most likely as well; but the molars are absolutely useless here.

Whereas dogs (and more specifically sharks) have "saw-like" teeth, that combined with strong neck muscles (and a propensity to grab hold, and shake vigorously, as if they're literally sawing away flesh), make them a lot more lethal to most land mammals.

If we include monkey eating habits, I don't see any large mammals on the list (all the mammals they may eat are smaller than them); compare that to the canid family, that will hunt down mammals many times larger than them. I just don't see how the monkey is built to be able to kill a human being.

Granted, it's going to hurt a lot to get bitten by a monkey. But I just don't see how a 40lb mammal can do that much damage. If you can somehow restrain it by the neck, it's basically over for any mammal of that size without claws (or another means of escape) -- which monkeys don't seem to have.

Now, if we're talking a chimpanzee? I'm going to do everything in my power to get out of that situation. But a monkey? A large dog is more of a threat.

That's all well and good until 5 of them jump on you and sink 2 inch canine teeth in you...

I feel after the first few bites, you'd be running on adrenaline.

At that point, I believe it's apt to start elbow-dropping, curb-stomping, and punting monkeys.

If for some unknown reason, 5 monkeys ambushed me on a regular walk, I'm confident I could throw enough of a fuss that'd dissuade them from trying to steal my lunch.

Now 10 monkeys? I don't know. That's a lot of monkeys.

I don't think I'm ever going to encounter 10 monkeys, all set on turning me into tartare.

However, if I were to have my jimmies rustled by 10 monkeys at the same time, I would put it at 2:1 odds that I survive without life-threatening injuries.

I would agree that you could dissuade a few monkeys from taking your sandwich. Animals don't particularly want to fight: even a "victory" could end badly if you live in a world without antibiotics, splints, or indeed any medical care.

On the other hand, if you backed five desperate monkeys into corner so that they think they are fighting for their lives, I think you'd fare much worse. I'd bet "punt attempts" sometimes end with the monkey clinging to your leg instead, chomping away at whatever they can reach (and even the molars can do some damage given the tremendous bite force).

Win, or injure the human so badly that they won't pick the fight again before the human kills it, assuming the human actually fights to kill?

I have no doubt it's not wise to fight a monkey, but I wouldn't expect it to actually win.