Commonly found around reefs and caves, whitetip reef sharks (Triaenodon obesus) are extremely docile creatures. These requiem sharks are nocturnal and can be found resting in caves during the day and hunting at night.
Whitetip reef sharks can be found in the Indo-Pacific waters of East Africa, Pakistan, Sri Lanka, Burma, Vietnam, Taiwan, Riu Kiu Islands, Philippines, Australia. They are also found in the Malay Archipelago (a group of islands that includes Brunei, East Malaysia, East Timor, Indonesia, Papua New Guinea, and the Philippines), as well as the Hawaiian and Pitcairn islands. In the eastern Pacific ocean, whitetip reef sharks reside in the Cocos and Galapagos islands, and from Panama to Costa Rica.
Whitetips spend their lives in or around the shallow waters of coral reefs, living in depths from 8 to 40 meters (26 to 131 feet). During the day, they spend their time in caves or deep crevices of reefs and have even be found to stack on top of each other while resting. Some species of sharks need to constantly be moving in order to breathe, but whitetips are able to remain in one spot for several hours at a time. Whitetips often live by the same reef or general geographic area for several years or even their entire life. Other shark species including the blacktip reef shark and grey reef shark also live amongst the whitetips where they all co-exist and live almost communally.
The most apparent feature of this species is the whitetips located on their dorsal (top) fin and caudal (tail) fin. Adult whitetips can reach lengths of just over 2 meters (about 7 feet) but commonly range from 1.5 to 1.8 meters (5 to 6 feet) in length, and average about 20 kilograms (44 pounds). They have a small and slender greyish-brown body and a white ventral (bottom) side along with dark spots or freckles on either side. Whitetips have a flattened head and a rounded snout. Their mouth and nostrils are ventrally located, and each jaw has 2 functional rows of about 20 to 25 teeth each. Their skin is extremely tough and their fins very flexible which allows them to survive in jagged coral reefs. The second dorsal fin is quite large in comparison to the silvertip shark and oceanic whitetip, two species commonly mistaken for whitetip reef sharks.
Despite being generally docile, when it comes to feeding time whitetips can become very aggressive. They are known to be clumsy and slow in open water, but because of their maneuverability, they are able to quickly catch prey within coral reefs. Typically lone hunters, whitetips will occasionally hunt together in pursuit of prey. Due to their ability to venture into crevices of reefs, whitetips are able to catch prey that other shark species could not.
Because they have a ventrally located mouth, they are excellent bottom feeders and can swiftly pick up crabs, octopi, lobster, and other seafloor dwelling creatures. Other prey includes damselfish, parrotfish, surgeonfish, goatfish, triggerfish, squirrelfish, and eels.
Whitetip reef sharks are very docile creatures with both humans and other sharks. Like essentially any shark, they may become aggressive if provoked or if they feel threatened. Whitetips do not stray far from their reef and will return to the same cave every day for months. 3 kilometers (1.9 miles) is the longest recorded venture of a whitetip reef shark over the course of a year. They are not a territorial species and share the reef with other animals, even sharks.
Reproduction & Lifespan
According to the behavior observed in captive whitetips, during mating, they will “orient themselves parallel to each other and at about a 45 degree angle to the water column during copulation. They position themselves with their snouts in the sea floor, maintaining this vertical position with occasional simultaneous undulations of their bodies. The male then bites the pectoral fin of the female and inserts his clasper into the cloaca.” The gestation period for whitetips is thought to be around 5 months, however, more research is needed to confirm this. 2 to 3 pups are born at a time, averaging about 60 cm (about 2 feet) at birth. Sexually maturity is reached around 5 years of age. Whitetips are believed to live up to 25 years.
The whitetip reef shark is currently considered “Vulnerable” on the IUCN Red List and is currently on a decreasing population trend. Humans are the most dangerous predator to the whitetip reef shark and any sea creature for that matter. Shark species all around the world, including the whitetip reef shark, are overfished for their fins and meat for food, cosmetics, or medicine, as well as being caught as bycatch. This has been plummeting shark populations drastically for decades. There are currently no conservation acts in place for this species, except for the fact they occur in at least one marine protected area. As a result of their small litter sizes and late maturity age, overfishing, and lack of protection, the whitetip reef sharks have a slow population rebound rate. This essentially means they cannot repopulate themselves as quickly as they are dying. It may not be so unreasonable to believe the whitetip reef shark will see endangerment in the near future.