I had also seen that viral pic. However, I regularly hike with a vet. During a winter hike, I stupidly repeated that the weakest wolf leads the pack. My friend immediately protested and said that while they do put she-wolves and older members in the middle and a strong young male goes last, the pack is always led by the alpha male (now I see from your link hat there's a dispute whether it's male or female - anyhow, it's the leader who takes the burden of ploughing thru deep snow).

My Sat experience only confirms common sense. If you sink knee-deep with each step, you cannot lead your pack for 9km if you are a weakling.
We had a woman of 66yrs among us, quite short and of a slim frame. She is quite fit, but we have to take into account the age. There were two "strong young males", three women in their 40s (all on the fit side) and I (the oldest male). I'd say I wasn't the strongest in terms of sheer physical strength, but I had what it takes to lead - the stamina and perseverance (and a mobile with GPS to control we were on the trail!)
So I took the lead, then I asked the bigger (and heavier) of the two guys to follow me.
The idea was for him to enter my footprints and make them bigger. Then the younger women followed, the oldest was one but last and a youngster closed the file.