At about 5 to 6 months, if you have more than one pup, you may
find that play becomes more aggressive and exhibits some
nipping, growling, and other general displays of dominance. Many
males, and some females, will begin humping each other at this
stage as they rehearse for their adult roles. Such behavior is
acceptable as long as it is not directed towards you. Puppies
can be taught to sit, lie down, wait, stay, leave it, and other
such useful commands that will stay with them for the rest of
their lives. Once these behaviors have been learned they should
be reinforced periodically throughout life. This is the usual
time for formal puppy training classes outside the home. Such
classes are extremely helpful as long as they are conducted in a
non-confrontational way. The following list will help you know
what to expect from your puppy has he develops. How Big? - Most
6-month-old puppies are approximately 75 % of their adult body
weight. Most puppies will gain or grow each week until they
attain their adult siz