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Today on animal fact files we’re talking about thresher sharks. These sharks are easy to identify because they have a long tail fin. The upper lobe of a thresher shark’s caudal fin, or tailfin, may be as long as the shark’s entire body! There are three thresher shark species and they range in size from the smallest, the pelagic thresher, which reaches 12 feet (365cm) in length, to the bigeye thresher shark which reaches 15 feet (461cm) in length, to the largest and most well known species, the common thresher shark, which can reach 18.8 feet (573cm) and possibly longer! Now, all these sizes are including that long caudal fin. Thresher sharks are considered not dangerous to humans, though, of course they should always be respected just like any other wild animal! Observations from divers indicate that these sharks are shy and will flee from bubbles created by SCUBA gear.

Thresher sharks are found throughout tropical and temperate waters around the world, though the different species have different preferences on where they live. The pelagic thresher shark is absent from the Atlantic ocean and, as suggested by its common name, is typically found out in the open ocean. Pelagic thresher sharks live from the surface to 492 feet (150m) below the waves. They may be seen on beaches with a narrow continental shelf and they’re occasionally seen on reefs near drop offs and seamounts. Common thresher sharks tend to stay towards the surface of the water and they’re often seen near land usually no more than 75 miles (120km) from the coast. They’re most abundant in coastal areas and their young are raised in shallow bays. Common thresher sharks may dive as deep as 1,200 feet (366m), but that’s not as deep as the deepest living thresher shark species. Bigeye thresher sharks may spend a lot of their time towards the bottom of the water column. During the day they may be swimming at 1,640 feet (500m) below the waves. Each night, they migrate vertically. These are called diel migrations and we’ve talked about them in previous episodes. Bigeye sharks spend a lot of time in a part of the ocean where oxygen is minimal. This is likely why they’ve developed gills with more surface area than most (if not all) other living shark species. Bigeye thresher sharks have grooves along their heads not present in common or pelagic thresher sharks. These grooves are here because a bigeye thresher shark’s gill chambers are extended and long gill filaments are housed under these unique grooves.

Pelagic thresher sharks can be told apart from common thresher sharks by checking out their color patterns: common thresher sharks have white above their pectoral fins where pelagic thresher sharks do not. Thresher sharks may also be known as fox sharks and these sharks’ hunting skills match their terrestrial namesake. Thresher sharks use their long caudal fins to slap and stun their prey. They may even gather fish together for a more effective smack. Thresher sharks are typically solitary, but they may travel in small groups of two or three and even hunt together using this slap and stun method. They may also completely jump out of the water to catch prey like marine birds.

Depending on the species and the sex of the shark, it may take three to more than ten years before a thresher shark begins reproducing. Considering these sharks only live approximately 20 to 30 years, that’s not a lot of time to produce offspring. And, to top it off, individual thresher sharks only give birth to a handful of pups each year, so their reproduction rates are quite low. It’s this reason these sharks are listed as either vulnerable or endangered to extinction. Sport fishing and hunting by humans are harmful to thresher shark populations. Natural predators to thresher sharks include other sharks, but their babies are born quite large to help prevent this! Thresher sharks range from 3.3 to 5.2 feet (100 to 160cm) at birth. They’re born live. Unlike some other shark species, thresher shark females provide unfertilized eggs for their developing young to eat while in the uterus, so thresher sharks don’t eat their siblings!

For more facts on thresher sharks, check out the links in the description. Thank you to Nemy for today’s request. Give a thumbs up if you learned something new today, and thank you for watching Animal Fact Files.