Gas Mask for Horses Training 1918 WWI US Army

Retreat of the Cavalry
The importance of horses in warfare dropped off over the centuries with each arrival of new, more deadly weapons. The development of powerful bows and arrows that could pierce horse armor, as well as the introduction of guns, meant that horses were no longer invincible. Even so, as recently as a hundred years ago, millions of horses were still used in battle.

The last hurrah came with World War I. At the beginning of that war, in 1914, cavalry charges, in which thousands of soldiers on horseback rode into battle together, were still seen as a major offensive tactic. But trench warfare, barbed wire, machine gun, and other modern developments effectively brought such charges to a dead halt. By the war's end, horses were still used behind the lines to transport guns and supplies, but their role in leading the attack had become a thing of the past.

The Last Roundup
Millions of horses died in World War I, even though by the end of the war their status had been reduced from leaders of the charge to a supporting role. The clash between old-fashioned ways of warfare and the newer technologies of death led to poignant sights like horses wearing gas masks, horses pulling guns larger than themselves, and horses lying dead next to heaps of mortar shells.

Poison Protection
To protect against the poison gases used in World War I, both soldiers and horses wore gas masks. Horses' noses were covered but their eyes were not, since horses could tolerate the poisons better than humans.

Horses In Modern Warfare
Although cavalry charges are now a thing of the past, there are still places where a horse is more useful than a truck. In 2002, for example, during the war in Afghanistan, some U.S. Special Forces rode horses in areas where the rugged terrain and lack of fuel made automobiles impractical.

Did You Know
The last cavalry charge made on horseback by the U.S. Army took place in 1942, when the United States fought the Japanese army in the Philippines. After that, the mounted cavalry was replaced by tanks.

An Exciting Start
World War I was a major turning point in the role of horses in battle. At the beginning of the war, a romantic view of battle still prevailed, as shown in a recruitment poster on exhibit.

A Harsh Reality
By the end of World War I, horses had proved as vulnerable as humans to new military tactics and technologies. And, just like human soldiers, millions of horses died in the war.

Horse-drawn Ambulance
As World War I progressed, horses were shifted away from their role in mounted cavalry leading the attack into more of a support role behind the lines. Horses were used to transport people and supplies.

https://www.amnh.org/exhibitions/horse/how-we-shaped-horses-how-horses-shaped-us/warfare/retreat-of-the-cavalry/

Photos and more information of the US M4 gas mask :

https://www.militaryhorse.org/forum/viewtopic.php?t=1891&start=20