The Harappans developed an efficient system of transport, as an urban economy could have been operational only if its modes of communication were effective. Oxen must have been the Harappans’ pack animals; long caravans of them could ensure movement of bulk goods.
Harappans never domesticated or used the donkey as a load carrier. It is the onager or khur whose bones occur more frequently than donkey bones at early Harappan sites. The camel bones at Harappan sites represent the Bactrian camel.
Bullock carts were the main means of transport on land. Discoveries at many Harappan sites have revealed that carts were often two-wheeled. Wheels were solid constructions of three accurately fitted planks cut into a circle and pierced at the centre.
The solid wooden wheel is perforce a small one. However, cart-ruts made in a road in Harappa indicate that the body of the cart was not very small compared to modern ones. Harappans preferred bullock carts as these were most suited to their unsurfaced roads.
The bullock cart can roll along uneven, humpy surfaces, unlike the lightweight horse chariot that was invented in the Iron Age and which requires a smooth road. Surfaced roads are mostly absent in Harappan towns.
The Harappan economic system depended largely on the river system which depended on boats. A river boat with a high prow and stern suitable for halting at steep river banks appears on a Mohenjo-daro seal impression.
There are two steering paddles and a deck cabin. Further, a clay boat model and a pot with the drawing of sailing boat have been found at Lothal.
Numerous representations of ships and boats on Harappan seals, and a terracotta model of a ship from Lothal, give as some idea of the mode of riverine and maritime transport.
It may be said that the urban-rural networks, specifically traffic in people and goods, depended on two products of advanced carpentry: the cart and the boat.