Arno was a young chimpanzee boy who lived with his father, the prefect, Veska, in the settlement known as Chalo. Arno was a distant relative of chimpanzee refugee, Galen. In 3085, Arno was playing with his pet dog when he discovered the crashed remains of the ANSA space vessel and excitedly ran to tell his father. Upon presenting his find to his father, he theorized whether the humans who created such a device may have been culturally superior to apes. Veska, enraged by the notion, harshly criticized Arno and warned him to never repeat such heresy again.
- Arno is the first ape we see in the TV series.
- The character of Arno was played by actor Bobby Porter. Porter returned in the episode "The Good Seeds" playing the role of a young farm-ape named Remus. Porter had already played Cornelius - the young son of Caesar in Battle for the Planet of the Apes.
- If you assume that the televsion series is in canon with the five Arthur P. Jacobs Films there is a clear continuity error. This character has a pet dog but in Escape from the Planet of the Apes and Conquest of the Planet of the Apes it is clearly stated that all dogs and cats died in a plague. However, some fanon has expanded upon the pet extinction, devoting essays to how humanity tried to find different animals such as reptiles and birds before believing monkeys would make ideal housepets. The fanon also states that despite extinction, rare sightings of dogs and cats were reported after the plague (with the same level of believability as someone seeing the Abominable Snowman). It could be assumed that a handful of dogs had an immunity to the plague, thus by Arno's time dogs have become a reintroduced species.