Another "what is it?" question

[black and brindle]

Here's a closeup of him and of the much more noble-looking (and much older) newfie cross

Besides simple curiosity I'm wondering if there are breed tendencies I should be looking out for which will emerge as he gets older. For now he's got a retriever-like temperament - friendly, outgoing, playful etc. Or is that just impossible to know in a Heinz?