Wolfhnd,
If I was faced with saving a child or my dog my instincts may kick in and I could elect to save the child. If it were an adult I'm afraid I have grown tired of stupid people because they are a danger not only to themselves but the fabric of society
I don't think this scenario reaches as far out as to envelope Christianity or even social ethics,
"My Dog" tends to relate as you said to your pack, the survival instinct is us is probably the strongest one we have, (except for those who instinct to be being right is stronger, but even this is a perversion of survival), but our survival instinct expands out to our family also.
Then the Instinct to save your dog is the same as self preservation, even when facing a child's drowning. Your dog has become like a part of your own body and you may not experience a choice any more than you would pulling your hand back out of a flame.
If you know that your dog would sacrifice himself for a child, then perhaps you might also come to sacrifice your dog for that child even though your dog still has the greatest value to you. There is no right or wrong in this situation, only two wrongs and what lesser wrong you think you could live with.
IOWs, the question becomes, "can I live with myself letting the child die" or "can I live with myself letting my dog die", there is thus no right and wrong, only bad and worse.
As for the religious aspect you brought up, just as some science oriented people like to claim evidence as if it is all nailed down in their understanding, this same psychology works it way out in religious theologies, but "religious People" have just as hard of a time understanding God as science does the universe, God is not so easily pinned down by man's theology (best guess). Rabbis considered in their ethical meditations that one could break one law to keep a higher law, so in this case perhaps being driven by the love for your friend and companion, could out weight a neglect.