Who is the Real Herd Leader?

A friendly greeting

Note: These feral ponies live at Assateague Island National Seashore. They are free-roaming, have a natural social order, and are protected from human contact. They are not involved in the controversial Chincoteague Pony Roundup.
So, is the real herd leader a dominant stallion? Or an alpha mare? Neither! Decades of research on free-roaming horses consistently shows their herd structure is not a dominance hierarchy; it’s family units with complex social relationships. Social bonds are more important than rank because survival depends on cooperation, not competition. Leadership is shared. Any individual can initiate movement, such as heading off to a water source, or seeking new grazing, but no one is required to follow. Horses decide whether or not to follow based on their social connections and on how reliable they consider the initiator. Experienced horses with the strongest social connections are most likely to be followed. Dominant horses are less likely to be followed; they tend to be avoided. More details on free-roaming herd behavior here: Pasture Politics, Social Skills, and Wild Horses

Aggression is rare among horses who live unconfined with resources spread out

Aggression is rare in feral bands except in self-defense or protection of fellow band members. The aggression seen in domestic horses is due mostly to confined spaces, concentrated resources, groups of unrelated and/or poorly socialized horses, and high turnover. Horses mistaken for leaders are often stressed-out resource guarders who are appeased to reduce conflict. This article explains “dominance hierarchies” in domestic herds. Do Horses Want to Be Dominant? To a horse, “dominance” and “leadership” are two different things. Leadership is not a power position; it is a responsibility shared by all adult members of the group.

Note: Researchers define "leader" as one who goes first and is followed voluntarily. Stallions "drive" from behind, and moving is not optional. That is not defined as leadership, but leading is not the stallion's role. His job is sentry, protector, and rear guard when the band is on the move. Although stallions are popularly characterized as aggressive, it has been noted that more peaceful stallions have more and healthier babies, and more loyal mares.

"Auntie" checking in with foal

This mare is not the foal's mother. Mares in the same band often have strong life-long bonds, and look out for each others' foals. Stallions also look after their offspring. This allows youngsters greater freedom to explore the world, expanding their knowledge and building confidence.

References:
"Who’s the Herd Leader? It Depends, Researchers Say"
by Christa Lesté-Lasserre, MA
https://thehorse.com/112546/whos-the-herd-leader-it-depends-researchers-say/
Robin Foster, “When the Herd Moves, Who Leads and Who Follows?”, The Horse, July 20, 2017
https://thehorse.com/110684/when-the-herd-moves-who-leads-and-who-follows/
A Practical Field Guide to Horse Behavior by Dr. Sue McDonnell
Horses in Company by Lucy Rees
"Horses follow reliable leaders" by Renate Larssen
https://horsenetwork.com/2023/02/horses-follow-reliable-leaders/
Hrefna Sigurjónsdóttir; Machteld C. van Dierendonck; Sigurdur Snorrason and Anna G. Thórhallsdóttir, “Social relationships in a group of horses without a mature stallion”, Behaviour, Volume 140, Issue 6, pages 783 – 804, 2003.
http://booksandjournals.brillonline.com/content/journals/10.1163/156853903322370670
Lea Briard, Camille Dorn, Odile Petit, “Personality and Affinities Play a Key Role in the Organization of Collective Movements in a Group of Domestic Horses”, Ethology: International journal of behavioural biology, June 16, 2015.
http://onlinelibrary.wiley.com/doi/10.1111/eth.12402/abstract
Konstanze Krueger a, Birgit Flauger a, 1, Kate Farmer b, Charlotte Hemelrijk c “Movement initiation in groups of feral horses”, Behavioural Processes Volume 103, March 2014, pages 91 -101.
http://www.sciencedirect.com/science/article/pii/S0376635713002222
Briard L, Deneubourg JL, Petit O., “How stallions influence the dynamic of collective movements in two groups of domestic horses, from departure to arrival”, Behavioral Processes, 2017 Sept
https://www.ncbi.nlm.nih.gov/pubmed/28549567
“Is leadership a reliable concept in animals? An empirical study in the horse”
Marie Bourjade, Bernard Thierry, Martine Hausberger, Odile Petit
https://pubmed.ncbi.nlm.nih.gov/26010442/