Tankers do not need a tailgate.

It appears that somebody took a "traditional" stake bed and removed the longitudinal stringers that formed the open fence and replaced them with panels, then put a (removable?) tank in between. What is odd is that stakes 1, 4, 6 and 8 appear to have been extended so that the panels run inside them instead of on the outside as in 2, 3, 5 and 7. The angle of the bends on the extended stakes seem to be sharper than the inside ones, which suggests they were replacements. All in all, fare enough from the likely original configuration that the caption is a tad misleading.

There are fence-like stakes, but they have metal "privacy" panels bolted to them, so there are no gaps to see through. The tank is merely the cargo, not an integral part of the truck.

This appears to be a tanker body. Stake bed bodies have an open fence type configuration.

[The stakes are bolted to the panels that enclose the bed, which the tank is resting on. - Dave]

what?