Good question! If look closely at the mouths of Predators, you'll notice that although they are frightening, they don't seem well designed for, well, eating food. How does a Predator masticate? Wolf Gnards studied the arrangement and apparent functions of all ten of an adult Predator's teeth and posed two hypotheses: either a Predator grinds food into a fine paste, like baby food, or swallows its food whole, like a snake. I'm inclined to support the Paste Theory:
Like Robocop, the Predators subsist off a "rudimentary paste that sustains their organic systems." The fact that Robocop eats baby food is pretty good evidence that a big, strong killing machine can thrive off the stuff. Baby food is probably also convenient for space travel like astronaut ice cream or Tang, or like military MRE’s (which are a little more like dog food, but I think a Predator might enjoy that more though). I do have a hard time believing that the Predator race has the manufacturing infrastructure and know-how to market and mass produce Brand X Predator baby mush (with the meaty gravy that babies craze). However, this same sentiment could also be suggested for spaceships/space travel. I like to imagine that faster than light travel requires more book reading and less laser shooting. Most likely if they do eat some sort of gruel it is composed of the bones of their fallen prey; any meat grinder would do in that case.
As for Cinnamon caching your 'valuables' with her own, I will recite the 'Dog Property Laws':
1) If I like it, it's mine.
2) If it's in my mouth, it's mine.
3) If I can take it from you, it's mine.
4) If I had it a little while ago, it's mine.
5) If it's mine, it must never appear to be yours in any way.
6) If I'm chewing something up, all the pieces are mine.
7) If it just looks like mine, it's mine.
8) If I saw it first, it's mine.
9) If you are playing with something and you put it down, it automatically becomes mine.
10) If it's broken, it's yours.
My Shih-Tzu, Cinnamon - I adopted her at about two years old and she is now about five years old. When I got her, she made it clear when she was happy --- but then a couple of months later me and others notices she started showing her teeth in what looked like a smile (easy for a flat-faced dog) whenever she was happy, content, or wanted something. I figured out that she learned our facial language and was imitating it. She was around a lot of people because my friend and I ran a therapy practice and also lived upstairs. Cinnamon was around a lot of people, plus she's a smart dog. Because we did group work with teenagers, we ordered a lot of pizza, well we also ordered a lot of take-out for ourselves too. We usually paid using petty cash. We also gave out a lot business cards.
After a while we started noticing Cinnamon putting stuff under her dog bed's pillow. Finally, when I went to launder it, I found a bunch of paper money, coins and business cards, along with bones and toys hidden under her pillow. This was fascinating. She must have seen money exchanged for food and somehow made a connection. Some sort of doggie cargo-cult? Weird and unexpected in any-case. We joked about her being Jewish, 'cause we're Jewish. We later learned her street-name is JewDawg...I kid, I kid.
Later, I did a bit of reading about dogs. Dogs do indeed imitate human expressions in a manner consistent with the situation. Maybe they pick it up 'cause their experiencing the emotion associated with the expression, or perhaps they know wearing the expression will get them something....expert opinion differs. Me? I believe it's a bit of both...just like what humans do. But...I do doubt dogs will use these expressions with each other - haven't tested this idea though.
I have noticed, however, that Cinnamon will use the smiling expression when she wants our parrot (also her friend) to toss her down a treat. When she makes eye contact and 'smiles' the parrot tosses some nuts down.
I have also noticed that Cinnamon constantly uses the 'smile' when she is scared of something, loud fireworks that are being set off where she cannot see them. If she can see them, she's okay, but unfortunately, we have neighbours somewhere in the 'hood who set them off. This causes her to have a knitted brow and the 'smile.'
Since I'm going to town on this monologue.... I would like to also mention that domestic dogs and humans have been shown -- in double blind studies to accurately read each others body language and facial expressions over 85 percent of the time for dog owners, but....more interesting....people with little or no experience with dogs are able to read their body language and facial expressions almost as well -- something like 70 or 75 percent of the time. I forgot the reference, I think perhaps it was in Nature (online.)
Apparently, Gretchen had learned to imitate my parents in their greeting of her, when they came home from work -- she had learned to mimic a human smile. I had known that dog all her life and had never known her to bite a human, yet that full display of inch long canine teeth stopped me in my tracks.