Other dogs will steal your food if you don't eat it right away. This is because they are hungry. You could hide it too.
Do What You can to Survive
If you disobay your master he will club you. On pg 42 Francois says "Now , by gar, I feex you." This shows that Francois is about to club Buck.
You Must be Fit for Survival
If you mistreat another dog he will fight you. On page 14 the text states "He had never seen dogs fight as these wolfish creatures fought." This shows that the dogs fought like savages.
You Might have to Kill your own Kind to Survive
You might have to team up with wild animals. Pg. 92 "Finally the wolf sniffed noses with him." This shows that he successfully teamed up with the wolfs.
You have to be the right breed or be fit for that enviorment. Dogs will short fur probally won't survive in the cold. But a dog that is larger and has more fur is more likely to survive.
You might want leadership, you might want to look tough, that might require killing someone in your own pack. On pg. 39 the text states "He had held his own with all the manner of dogs and achieved mastery over them." This shows that he fought many times for many reasons.