Tribal Latin Americans, around 1600 BC:
Ancient rubber was made from latex of the rubber tree (Castilla elastica), which is indigenous to the tropical areas of southern Mexico and Central America. The latex was made into rubber by mixing it with the juice of what was likely Ipomoea alba (a species of morning glory), a process which preceded Goodyear’s vulcanization by several millennia. The resultant rubber would then be formed into rubber strips, which would be wound around a solid rubber core to build the ball.
Archaeological evidence indicates that rubber was already in use in Mesoamerica by the Early Formative Period – a dozen balls were found in the Olmec El Manati sacrificial bog and dated to roughly 1600 BCE. By the time of the Spanish Conquest, 3000 years later, rubber was being exported from the tropical zones to sites all over Mesoamerica.
Think dodgeball, plus poison-tipped spears.
Incidentally, the next major evolution of rubber appears to be by Goodyear:
Goodyear is credited with inventing the chemical process to create and manufacture pliable, waterproof, moldable rubber.
Pictured is the Zeppelin NT, Goodyear’s first new airship design in 45 years, released in 2014. I used to drive by the Goodyear eastcoast hangar on the way to the office.