While heading into Safari Zone, the Sole Survivor runs into Cito, fighting off a gatorclaw. After putting the reptile in the ground, Cito asks for help. The Survivor obliges, planning to provide the park for his gangs.
Head to the Safari Zone and help Cito kill the Gatorclaw.
Follow him to the Primate House and talk to him to receive the first McDermot holotape. Listen to it.