White Tip Reef Sharks
Highlights
- Scientific Name: Triaenodon obesus
- Status in the Wild: Threatened
- Habitat: Oceans
- Diet: Carnivore
White tip reef sharks are by far the most common shark in Costa Rica, frequently encountered along the country's Pacific Coast – from the Bat Islands all the way to the Osa Peninsula and Cocos Island. This sleek breed, Triaenodon obesus, is a non-aggressive species of the requiem family of shark. These migratory fish thrive in extremely warm and shallow waters, and are best known for their round eyes, broad heads and the tell-tale blotches of white on their dorsal and caudal fins.
read more closeFairly small in size, white tips typically weigh around 40 pounds. They rarely grow to be larger than 5.2 feet long, and have a life expectancy of about 25 years. Most varieties of shark swim constantly in order to breathe, but the white tips seldom ascend to the surface for respiration since they have the extraordinary ability to pump water through their gills while lying still. Their tubular, whisker-like nasal flaps may give the fish an intimidating appearance, but the species is surprisingly tranquil and tolerant in temperament.
White tip reef sharks have long, streamlined bodies that are perfectly structured for hunting crabs, octopi, eels, lobsters, parrotfish and other creatures that like to hide in narrow rock crevices. Their mouths contain two rows of between 42-50 teeth each. White tips also have a heightened sense of smell and hearing, along with refined electrical sensory capabilities for detecting prey. They see visual stimuli in terms of movement rather than detail. These predators tend to hunt solo and at night – although they have been observed collectively scouring reefs in large legions, destroying sizable hunks of coral to expose crustaceans and bony fish. Amazingly, the sharks can survive without food for up to six weeks.
Habitat:
White tip reef sharks are Indo-Pacific fish that can be found along the shores of Africa, Southeast Asia, and the Americas – particularly in Costa Rica, Panama, and the Galapagos Islands. Schools of hundreds of these animals can be found at Cocos Island, located about 310 miles off of Costa Rica's southern Pacific shores. They prefer to live at shallow depths of 26-130 feet, among coral reefs, or in lagoons and shallow depressions in the ocean floor. Divers in Costa Rica will likely spot white tip reef sharks when exploring popular sites off Playa del Coco, Manuel Antonio and Cano Island.
White tip reef sharks are fairly social creatures. When not perched solo in a cramped cave, they are most often observed resting on the sea floor in groups of six to twenty individuals (although at Cocos Island they are often found in schools of 200 or more) – commonly stacked on top of one another like firewood. They tend to live in the same area for the majority of their lives, with an average range of movement of .019 square miles during the day and .39 square miles at night. White tip reef sharks are not at all territorial, enabling them to live peacefully with other reef-dwellers. Unafraid of humans, these creatures can have a curious disposition – and have been known to terrify new divers with their method of approach. They often swim quickly toward underwater explorers as if preparing to strike, but rapidly change course at the last possible second.
Reproduction:
Male and female white tips mature at age eight, when they reach about 3.5 feet of their eventual 5.2-foot size. These graceful animals are viviparous, meaning that embryos live inside of their mother as opposed to outside in an egg. Female sharks have one working ovary and two uteri, and give live birth of one to five pups every two years. The average female delivers about 12 pups in her lifetime.
Mating habits are somewhat violent. Many males will follow and harass a female, nipping at her fins and body. Finally, one (and sometimes two) will succeed in dragging her down to the bottom by his teeth. Then the pair thrashes around for one and a half to two minutes, during which time the male shark is unable to breathe. The female then swims away from the encounter impregnated and bleeding from the fins. After a gestation period of 10-13 months, she will give birth.
Status in the Wild:
White tip reef sharks are currently in the lower risk/near threatened category on the IUCN Red List. Due to their shallow habitats and slow reproduction habits, white tips are in danger of impeded recovery from the effects of overfishing in many parts of the world. Natural predators include tiger, Galapagos, and silvertip sharks.