I failed to get far enough away to get a proper photo of the Buffalo, so here is an old B&W
The LVTs were originally based upon a tracked civilian rescue vehicle called the Alligator. The military version was intended solely as a cargo carrier for the US forces to transport support materials from ship to shore, but they quickly became useful for assault and fire support tasks as well.
The LVT series slowly evolved over time, standardising on drivetrains and tracks used in other readily available tanks. Each iteration shuffled the engine and crew compartment around until, by the time the LVT-4 came into being, everything was at the front, leaving the entire back section as the transport area. This made it large enough to carry both troops (up to 30) or small vehicles or artillery. Over 8300 of these were produced.