According to Grove, the unique elements in the headgear can also be recognized in headdresses of human figures on other Gulf Coast monuments, suggesting that these are personal or group symbols.
The heads range in size from the Rancho La Cobata head, at 3.4 m high, to the pair at Tres Zapotes, at 1.47 m. Some sources estimate that the largest weighs as much as 40 tons, although most reports place the larger heads at 20 tons.
The heads were carved from single blocks or boulders of volcanic basalt, quarried in the Tuxtlas Mountains. The Tres Zapotes heads were sculpted from basalt found on San Martin Volcano. The lowland heads were possibly carved from the Cerro Cintepec. It is possible that the heads were carried on large balsa rafts from the Llano del Jicaro quarry to their final locations, or more likely dragged and rafted down rivers. To reach La Venta, roughly 80 km (50 miles) away, the rafts would have had to move out onto choppy waters of the Bay of Campeche.
Some of the heads, and many other monuments, have been variously mutilated, buried and disinterred, reset in new locations and/or reburied. It is known that some monuments had been recycled or recarved, but it is not known whether this was simply due to the scarcity of stone or whether these actions had ritual or other connotations. It is also suspected that some mutilation had significance beyond mere destruction, but some scholars still do not rule out internal conflicts or, less likely, invasion as a factor.