Creature Feature – Get to Know the Thresher Shark
If you’re a shark lover, the amazing, but notoriously shy Thresher Shark would definitely be in on your hit list of dream sharkie experiences! To get you fuelled and planning for that dream encounter, here’s a couple of amazing Thresher facts!
It’s the one thing that stands out more than anything else – that amazing whiplash of a tail! The super long upper caudal fin measure half the length of their body – in an adult Thresher Shark, this can be as long as 3 metres! It’s certainly the most eye catching and flashiest tail in the shark kingdom! As you can see by the drawing on the right (sourced from CITES), all 3 species of the Thresher shark – the Common Thresher, Pelagic Thresher, and Bigeye Thresher have slender, torpedo like muscular bodies, furnished with that ultra long tail! (P/S – CITES does amazing work to conserve and protect the marine environment – be sure to check them out!)
Their closest relatives are the basking sharks and mackerel sharks – wouldn’t that be an amazing family reunion photo!
Stun Force Hunting
That tail isn’t just for good looks! Threshers use their tail like a whip – unleashing it to stun their sardine and tuna prey with amazing efficiency. First observed in 2013 by Simon Oliver, lead investigator of the Thresher Shark Research and Conservation Project in the Philippines, the sharks lunge into a school of fish, then swipe their tail in a trebuchet like motion, 180 degrees in just one third of a second! The illustration on the left, from his research paper “Thresher Sharks Use Tail-Slaps as a Hunting Strategy“, just shows how much power there must be in that shark! As hunting techniques go, this is definitely one of the most visually spectacular! This tail swipe creates a stunning shock wave that hits the fish, allowing the Threshers to pick them off at their leisure. Threshers have weak jaws and small teeth in comparison to other sharks, so this hunting method definitely evens up the odds. Sometimes Threshers will even slice the fish in half with their tails before eating. Now that’s hunting with style!
All Threshers belong to Family Alopiidae, and Genus Alopias. Where did this name come from? Well, they were first described by no less than Aristotle, the famous Greek philosopher, in his book Historia Animalia. Aristotle describes Threshers as being super cunning, and attributes abilities to them such as being able to bite through fishing line to escape, and even protecting their young from predators by temporarily swallowing them. Now these behaviours are not scientifically accurate, but it led Aristotle to really rate the intelligence of these sharks, consequently naming them “Alopex”. In Greek, Alopex means fox – a super cunning animal.
Threshers are one of the few shark species that are endothermic. This means that they can keep their blood, and body, warmer than the surrounding water. They have special muscles and a countercurrent exchange system in their blood vessels, which allows them to manage their blood pressure internally, and retain metabolic heat generated from their muscles. Threshers can maintain their body temperatures up to 4 degrees Celsius warmer than the surrounding waters. Staying warm allows them to be super quick swimmers, and mentally agile hunters. All the better to allow them to wield that fancy tail as a whip!
Yes readers, we have some breaching sharks! Thresher Sharks are known to fully jump out of the water, using that amazingly elongated tail to propel them clean up into the air, tail and all! With that awesome whiplash tail, I think they are definitely the high jump champion of sharks! Why do they do this? Honestly, we just don’t know, just as we don’t fully understand why dolphins, and mobulas breach. Maybe it’s to impress the ladies? Or maybe they’re just jumping for joy! They’ve even been known to breach several times in quick succession – might be a bit of showing off going on!
Threshers are pelagic sharks that prefer deep, open ocean. Scientists believe they spend most of their lives at a depth of 550m, with seasonal migrations in the open ocean. Threshers are usually found in tropical and subtropical waters. They do come up to coastal waters and continental shelves to breed, and juveniles will stay in shallower waters until maturity. This all contributes to their reputation of being one of the shyest, and most elusive sharks around.
So how can the avid shark lover catch a glimpse of these elusive deep loving sharks? Well, it turns out that these sharks are plagued by small parasitic flatworms. Threshers therefore present themselves at special cleaning stations on the continental shelves, where specialist reef cleaner fish will pick off parasites, and also remove dead tissue. When these cleaning stations are within the depths of recreational diving (such as in Monad Shoals in the Philippines) scuba divers get a rare eye to eye chance to marvel at these exquisite sharks!
Interested in opportunities to get your own close up encounter with Threshers? Dive Ninjas has upcoming expeditions to Thresher shark hotspots in the Philippines! Contact us today to find out more, or sign up!
Ninja Family Guest Writer:
Lover of all marine animals big and small – and ok, yes, I like diving a lot! When not underwater, I can be found in London with my goldfish.
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