Fun fact from the CSM on 'horses and bayonets'...
Well, the bayonet thing is easy to elucidate. The Marines and the Army both still issue rifle-mounted knives to serve as hand weapons, utility knives, saws, and all-around handy items.

Bayonet training is an integral part of the Marine Corps Martial Arts Program, which every recruit must pass. During such training, recruits fix OKC-3S bayonets underneath the muzzles of their rifles, effectively turning it into a spear. They’re taught thrusts, jabs, and slashes, according to a Marine public affairs account of such training. They then must use these techniques on a dummy-filled course intended to simulate close combat.
Bayonets are still issued and are required training for marines.