Night time in the depths of Cocos Island, where every crevice, rocky outcrop, and coral cave becomes a place to spend the night. Not a home, but a hiding spot from the danger that's lurking in the dark. My name is Filipe DeAndrade, and I'm a National Geographic wildlife filmmaker. It looks one of the alpha males, and then a juvenile male. My passion for animals has taken me across the world and given me a deep appreciation for this Earth. For season two of Untamed, we'll be exploring one of the most biologically diverse countries in the world. Costa Rica. There are few places in the world that endure seemingly unchanged by human kind. Cocos Island is one of those places. Life exists here in abundance. With wide open spaces, plentiful opportunities to find a mate, and water bursting with potential prey, this is a paradise for marine life. Cocos Island offers a refuge for one of the ocean's most important animals, sharks. Tigers, Galapagos, and hammerheads are just some of the more prominent species here. But the White Tipped Reef shark might be the most intriguing in the area. A small, elegant species, with a split personality. The largest weighing in at only 40 pounds, these slender carnivores spend their days resting on the ocean floor. This might not be exactly what you think of when you imagine a shark. But don't be fooled by this tranquil scene. When night falls, they reveal another side. The only way to film them in action is to follow them into the dark. Unlike many other sharks, white tips hunt in loose packs. Scouring the reef for any fish unlucky enough to be caught on its own after dark. Their elongated bodies allow them to dig deep into crevices. Larger sharks aren't able to fit in this maze of corals, giving the white tips exclusive feeding rights. Sharks have very acute senses. Their advanced eyesight allows them to see in minimal lighting, but when visibility drops below a certain point another powerful sense takes over. It's called electroreception. And it helps them to detect electrical signals, like the heartbeat of a frightened fish. Luckily for this guy, pufferfish is not on the menu. Hiding is the best strategy. But even then, just a millionth of a volt of electricity from their own beating heart could betray the fish. The sudden burst of energy sends the sharks into a frenzy. Their hearing perfectly attuned to the sound of a struggling fish. Sharks swim from all over to compete for the kill. As quickly as the frenzy began, it's over. The sun begins its slow climb back up into the sky, signaling to these predators that it's time to rest. This eternal dance between predator and prey is necessary. It's what keeps the balance in the ecosystem. And for apex predators like the sharks it's their role to drive evolution and make sure that only the strong survive.