In the 1930s Colonel Tooey, a concessionaire who operated the "Jungle Cruise" boat ride, established the first troop of wild rhesus monkeys on an island in the Silver River. He planned to use the attraction of the colony as one of the sights on his Jungle Cruise, but did not know that the rhesus monkeys were excellent swimmers. They quickly escaped the island, forming their own feral troops along the river. Rhesus monkeys are still seen along the river.[5]