Not the feature in many modern pop culture books but many cultures have roots in it.
I know this is a subject that no one really likes to talk about it, but this is part of Vietnamese and other cultures so lets just get over it.
Heads of dogs and other animals seem to be popular in numerous countries, camels, squirrels, monkeys, cats, rats, bats are all eaten. So, let us not get alarmed when the Vietnamese eat dog, as these delights are also enjoyed in some regions by Koreans, in North East Thailand, some parts of China, East Timor, Indonesia, Ghana, Nigeria and the Philippines.
Funny fact: in the North East of Thailand they only eat black dogs.
In Siberia, Alaska, northern Canada and Greenland sled dogs are known to be eaten when no other meat is available.
Many countries that once ate dog meat in the distant or ancient past, now all have laws regarding that and general consensus as taboo foods especially as dogs as pets become more popular. These include: Canada, Hong Kong, Taiwan, France, Germany, India, Mexico, Poland, Polynesia, and even in Switzerland once considered dog on the menu as a good thing.