<P> The game is played with a round leather football made of 18 stitched leather panels, similar in appearance to a traditional volleyball (but larger), with a circumference of 68--70 cm (27--28 in), weighing between 480--500 g (17--18 oz) when dry . It may be kicked or hand passed . A hand pass is not a punch but rather a strike of the ball with the side of the closed fist, using the knuckle of the thumb . </P> <P> Until 1870, rugby was played with a near spherical ball with an inner - tube made of a pig's bladder . In 1870 Richard Lindon and Bernardo Solano started making balls for Rugby school out of hand stitched, four - panel, leather casings and pigs' bladders . The rugby ball's distinctive shape is supposedly due to the pig's bladder, although early balls were more plum - shape than oval . The balls varied in size in the beginning depending upon how large the pig's bladder was . Because of the pliability of rubber the shape gradually changed from a sphere to an egg . In 1892 the RFU endorsed ovalness as the compulsory shape . The gradual flattening of the ball continued over the years . The introduction of synthetic footballs over the traditional leather balls, in both rugby codes, was originally governed by weather conditions . If the playing surface was wet, the synthetic ball was used, because it wouldn't absorb water and become heavy . Eventually, the leather balls were phased out completely . </P> <P> Rugby league is played with a prolate spheroid shaped football which is inflated with air . A referee will stop play immediately if the ball does not meet the requirements of size and shape . Traditionally made of brown leather, modern footballs are synthetic and manufactured in a variety of colours and patterns . Senior competitions should use light - coloured balls to allow spectators to see the ball more easily . The football used in rugby league is known as "international size" or "size 5" and is approximately 27 cm (11 in) long and 60 cm (24 in) in circumference at its widest point . Smaller - sized balls are used for junior versions of the game, such as "Mini" and "Mod". A full size ball weighs between 383 and 440 g (13.5 and 15.5 oz). Rugby league footballs are slightly more pointed than rugby union footballs and larger than American footballs . </P> <P> The Australasian National Rugby League and European Super League use balls made by Steeden . Steeden is also sometimes used in Australia as a noun to describe the ball itself . </P>

Why doesn t the nfl football have stripes