Monsieur Mallah was an ape who was taken by the Brain and experimented on, raising his IQ to the level of a human genius. Mallah served as the Brain's right-hand man for many years in the Brotherhood of Evil.
Note:In Post-Crisis/New Earth continuity, Mallah died in a battle with Gorilla Grodd. [Salvation Run vol 1 #4 (Apr 2008)]