This link is for Pekingese not chilhuahas.
Evidence of small dogs has been found in ancient Toltec and Mayan tombs .

This is not always the case
Having had many rescue and foster dogs and always helped in shelters not all abused dogs bite your hand off .
Some are so pathetically grateful they don t care what you do .
Some are so really starving they don't notice if you touch them or not while eating .
Others of course are possessive but then so are none abused dogs who have not been taught as pups that being possessive around food is a no no .
Having said that dogs should be left in peace to eat their food the same as anyone else..
I think most people get bitten by dogs that have not been abused -often a pet that has been allowed to get the upper hand .
The simple fact is that some people are not really good with dogs . I have seen so many dogs out of control or unsafe and the owner makes endless excuses -kids teased him he's been abused she's nervous etc etc what they are really making excuses for is their lack of dog handling skills

Most of the time they are just incompetent to have a dog .
They may be perfectly nice people they just should not have a dog which can be dangerous in the wrong hands.