monkey
猻 centers on a monkey, specifically referring to a kind of monkey in classical usage.
猻 combines the animal radical 犭 with 孫, which likely provides the sound. The character is used for a type of monkey.
The animal radical 犭 hints at a creature, and 孫 (grandchild) suggests a playful, smaller relative—picture a monkey as the mischievous grandchild of the animal kingdom.
For ソン, imagine a monkey playing with its son: son -> ソン, and the monkey 猻 is teaching its son to climb.