Because they are small, they are able to move quickly and easily across the coral reef. Staying under protective crevices and lying still on the sandy bottom during the day are other ways they use their small size as a means of adaptation. Their slender, more spindle-shaped bodies also help them maneuver around caves and walk on the sandy bottom of the coral reef. Their most important adaptation, for me, is their countershading. Whitetip sharks have a light gray color on the dorsal side and a whiter color on the ventral side. As they hid in the crevices of the rocks of the coral reef exhibit, their gray dorsal tops almost blended in with the darker gray color of the rocks under which they hovered. Because they are carnivores in the coral reef food chain, they eat the smallest fish, which keeps the population of these species from becoming too large. The population of these fish, or shark food, is a biotic factor for the whitetip shark. An abiotic factor is sunlight and oxygen. Without sunlight, they do not have the ability to see well in the water, and without oxygen underwater, they would not be able to breathe. As they live in the coral reef, their adaptations and biotic and abiotic factors help them make a living.