HCA: Hermit Crab Association

My friend has some palm trees in her yard and gave me a whole bundle of berries from them so that I could feed to the crabs.
I'm not entirely sure what type they may be so I figured I'd ask here to get your input.
I do know that there are some palm tree berries that are deadly to dogs, but again, i'm not sure what type those are.
Here's an image of what they look like.


These palm trees are growing in New Mexico (non-native) and start as green berries and eventually turn a purple color. Are they Acai berries?

I want to be sure that they're safe before I feed them, so any input would be great! She's had these palm trees for quite a while and isn't sure what the name is.

If they are indeed safe, are other parts of the palm tree edible as well?
Calla, Wode? Your expertise is needed!

Maybe this article will help you to identify it? http://davesgarden.com/guides/articles/view/3242/

Thanks for the article Calla! It was definitely informative, but rather confusing.
They don't seem to be any of the "dangerous palms" but i'm not entirely sure which of the "edible palms" they are. I'm leaning towards Acai just based on the color, but the palms are thick (not thin like in the pictures) the berries also don't appear to grow in strands (like the pictures)
So my next guess is that they're the California Fan Palm (Washingtonia filifera) though these may actually be it's sister, the "Washingtonia robusta" which apparently are common in New Mexico. But those appear to have tiny beebee sized fruits, and these are bigger than a beebee but smaller than a quarter...
So perhaps they are some sort of Washingtonia, but then again i'm not too sure

Maybe try calling the botany department of a nearby University. Or even a local botanical garden? They might be able to give you a better idea of what species of palm this is and whether or not it's known to be toxic.