Fingers was a gorilla imbued with human intelligence.
Born in Africa, the ape that would become known as "Fingers" suffered a traumatic experience. He was separated from his mother by a poacher named James Van Dyle. Fingers was sold to Gotham State University, where he was used in a laboratory run by two zoologists. He lived most of his life under their care, and was even given his name by the sons of one of those scientists.
Fingers was a test subject in an experience to boost animal intelligence. He was spliced with enhanced human DNA, which instantaneously bestowed him with human intelligence. Fingers went berserk and broke out of the laboratory. Confused and disoriented, he roamed in the streets, spreading panic. He eventually caught the attention of Batman, who tried to ensnare him. However, Fingers eluded capture and hopped on a high speed train.
Fingers went into hiding until he saw a news report about Van Dyle on the Web, and went on a rampage to find him. He was approached once again by Batman, and, after fighting him off, told him about Van Dyle's real poaching expeditions. Fingers wanted to know where Van Dyle had sent his mother. Batman tried to convince him to stay off the streets while he tracked down Van Dyle to bring him to justice. Fingers gave him until dawn to accomplish that; otherwise he'd go back to the streets and terrorize the citizens. A few hours later, Fingers got tired of waiting so he went after Batman at the Wildlife WayStation. He arrived just on time to save Batman from being eaten by lions.
After the ensuring battle, Fingers confronted and accused Van Dyle of abducting him and his family. He asked the poacher where his mother was, but Van Dyle didn't remember, claiming that for him she was "just another gorilla". Enraged, Fingers came to the brink of murdering him. However, Batman talked him out of it, by appealing to his reason. Bruce Wayne returned Fingers to the jungle and offered him a means to reverse the gene splicing that gave him his intelligence. Fingers rejected the offer, vowing to use his intelligence to protect wildlife from poachers. Terry McGinnis expressed concern that Fingers knew his and Bruce's identities and could be a security risk. Bruce, on the other hand, thought they had found a kindred spirit and ally who would keep their secrets.
Powers and Abilities
As a gorilla, Fingers naturally has superhuman strength, enough to take on Batman in hand-to-hand combat. Also, being spliced with human DNA, he was able to speak the human language and have considerable intelligence.