Who leads a wild wolf pack?

The parents. A wild pack is almost always a family group - a breeding pair and their offspring from the last few years, who disperse as they mature - so the leaders lead because they are the mother and father, not because they won anything.

The alpha idea came from watching the wrong animals. A 1940s study observed unrelated captive wolves crowded into an enclosure, a situation no wild wolf is ever in, and recorded exactly the tension and dominance fighting that produces. David Mech popularised the term in a 1970 book, spent decades afterwards trying to retract it, and asked his own publisher to stop reprinting the book. The correction never caught up with the vocabulary, which is now firmly lodged in human self-help writing on the strength of a misreading of some stressed captive animals.

What packs actually do is teach. Bringing down animals many times a wolf's weight takes several individuals working in relay over long distances, and yearlings stay on partly because they are not yet good enough to leave. When a breeding wolf is killed, the pack frequently fragments entirely - which is why culling programmes aimed at reducing livestock predation have sometimes increased it, by replacing one experienced family with several inexperienced fragments.