Unusual pattern choice for this modern high end obi, inspired by the famous Zo to Kujira-zu byôbu (Elephant and Whale folding screens) painted by mid-Edo animal lover artist Ito Jakuchu.
Those folding screens were rediscovered in 2008. There is apparently no hidden allegory behind the whale/elephant pairing beside the fact that artist once saw an elephant and a whale and (rightly) went "well they're neat".
Those screens were ordered to be displayed during Gion matsuri, and whimsical patterns were often favored for this occasion.
The largest festival in Japan has taken place every July since 869. Its original purpose was to purify and pacify entities responsible for plagues and earthquakes.