I should have mentioned that our university is on vacation now, and that the exact information on the lobos in the US, ( about 250, if i remember well, but these includes reintroduced lobos) i will look up if you remind me in september, though let me see if naturalia has that online, but i think they only list the mexican lobos. In the meantime, it can be mentioned that pairing mexican wolves can be very difficult. For example, Yuma at Los Coyotes was very special with her potential mates, and rejected a few. Finally she accepted an elderly male, Canek, from the zoologico de san juan de aragon. Yuma is a great mother, and her 3 lobitos are growing well. On the other hand Joy at chapultepec zoo, accepted her mate from the very beginning. Joy was also a great mother and raised various lobitos at chapultepec.