It has been described before that the occurence of reindeers is strangely low, while this was the main food source. But isn't it even stranger for dogs? Recent genetic research suggest that dogs were domesticated a lot earlier than any other animal, which makes sense for hunters. The distinction between dog and wolf may become blurred over long times - and while e.g. chauvet cave pictures a wide variety of wild predators, even owls and hyenas, no wolf is pictured either.
Were dogs/wolves too 'ordinary' to be portrayed here, more so than reindeer?