Monkeys of Costa Rica show many important behaviors at night, even though they are not fully nocturnal animals. Howler monkeys are especially active in the early night hours and just before dawn, producing deep resonating calls that help troops establish territory, communicate location, and strengthen social bonds. These calls are some of the most iconic sounds in Costa Rica’s rainforest and can be heard miles away. Spider monkeys, capuchins, and squirrel monkeys typically choose sleeping trees with dense foliage to protect themselves from predators like owls, snakes, and wild cats. Although they sleep through most of the night, travelers may hear them shifting positions, grooming quietly, or reacting to disturbances in the canopy. Night tours led by expert guides train visitors to listen for subtle sounds such as leaf rustling, canopy movement, and faint calls that indicate troop behavior. Naturalist explanations highlight how monkeys conserve energy at night and prepare for early-morning feeding cycles. Visitors also learn how moonlight, temperature changes, and weather conditions influence nighttime monkey behavior. Many night tours blend acoustic observation with sightings of frogs, insects, spiders, and nocturnal mammals that share the same habitat. Experiencing monkeys at night gives travelers a deeper understanding of the rainforest ecosystem and reveals behaviors that cannot be seen during typical daytime tours.