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Creature Feature: Thresher Sharks



In this new series, the Shark Trust will be sharing amazing facts about different species of sharks and what you can do to help protect them.

This month they’re showcasing the super agile, fish-herding, thresher sharks. Made up of 3 different species, these sharks can whip up dinner at lightning speed…

Thresher Sharks are found in tropical and temperate seas all over the world. Highly migratory, they spend their time in coastal waters as well as the wide-open ocean. By day you’ll likely find them in deep waters, avoiding predators and dining on squid and octopus. But at night, they rise to the surface to hunt small fish.

During daylight hours they may also indulge in a spa. Taking regular trips into shallow coastal waters to visit cleaning stations. Here they get preened and pampered by hungry cleaner fish, who remove pesky parasites picked up during their long travels.

Yet, they are capable of doing this themselves. When cleaner fish are off duty, threshers will remove parasites by breaching out of the water. Check out the photo below – what an incredible sight to see!

To survive in cold deep waters, threshers – like the White Shark and Shortfin Mako – are endothermic. They have a network of tiny blood capillaries, which acts as a heat exchange system. Known as a rete mirabile, this keeps them nice and toasty. In fact, their body temperature can be 10°C warmer than the surrounding water.

But the most distinctive and exciting adaptation of thresher sharks is – of course – their incredibly long, whip-like tail. Shaped like a scythe, this marks impending doom for schooling fish. Making up around half the length of their entire body, their tails can reach up to 3m long! And they’re not just for show…

Hunting in small packs, threshers will use their tail to herd small shoaling fish – such as mackerel, herring and sardines. They’ll then charge into the shoal, thrashing their powerful tail, injuring and stunning their prey. Dazed and confused fish are then swiftly eaten. Larger individuals will also feed on bigger fish, like cod and tuna, as well as large deep-sea squid.

The first part of the thresher sharks’ scientific name is ‘Alopias’, which is Greek for fox. In ancient Greece, the philosopher Aristotle thought these sharks must have been as clever as a fox to avoid the nets and traps of fishermen. But sadly, this isn’t the case today. Due to modern destructive fishing practices, all 3 thresher shark species now face a high risk of extinction.


Bluish to dark grey in colour, the Common Thresher has a pointed snout and small arched mouth.

Depending on the region, females reach maturity between 3 and 13 years. Males between 3 and 8 years. Females will give birth to litters of 2-6 pups in spring/summer, which can be as large as 1.5m! They’re thought to live up to 38 years.

  • SCIENTIFIC NAME: Alopias vulpinus
  • FAMILY: Alopiidae
  • MAXIMUM SIZE: 5.8m
  • DIET: Fish and squid.
  • DISTRIBUTION: Most tropical and temperate seas around the world. They have a higher tolerance for cold water, than other thresher shark species.
  • HABITAT: Coastal waters to the open ocean, from the surface to 650m deep.


As their name suggests Bigeye Threshers have enormous eyes. These help them navigate and hunt in deep dark waters, and at night. Their eyes can be up to 10cm in diameter and sit within a keyhole-shaped socket, enabling them to rotate their eyes upwards.

Purple to brown-grey in colour, they have the most beautiful metallic hues on their back and flanks.

After a 12-month gestation period, females will give birth to litters of 2 (rarely 4) pups. These can be up to 1.4m long and may live up to 20 years.

  • SCIENTIFIC NAME: Alopias pelagicus
  • FAMILY: Alopiidae
  • MAXIMUM SIZE: 4.8m
  • DIET: Fish and squid.
  • DISTRIBUTION: Most tropical and temperate seas around the world.
  • HABITAT: Coastal waters to the open ocean, from the surface to 500m deep (usually 100m).


Out of the 3 species, Pelagic Threshers are the smallest and least well-known. Similar in colour to the Bigeye but lighter. They give birth to litters of 2 pups every year and are thought to live around 19 years.

  • SCIENTIFIC NAME: Alopias pelagicus
  • FAMILY: Alopiidae
  • MAXIMUM SIZE: 3.6m
  • DIET: Fish and squid.
  • DISTRIBUTION: Indo-Pacific Ocean
  • HABITAT: Coastal waters to the open ocean, from the surface to 300m deep.

Discover more with the Thresher Shark Activity Bundle. Brought to you by award-winning outdoor education provider – The Great Out-Tours.

Created for children and adults in care homes, these bundles of fun will provide hours of entertainment.

Wordsearches, jigsaws, arts and crafts, educational videos, a family quiz and so much more. All jammed packed into this bundle for just £1, with 15p going to the Shark Trust!

Image banner: Thresher Shark © Matt Newell

The Shark Trust is the leading UK-based shark conservation charity. The team works globally to safeguard the future of sharks, and their close cousins, the skates and rays. Engaging with a global network of scientists, policymakers, conservation professionals, businesses and supporters, to further shark conservation. Established in 1997 to provide a voice for UK sharks, the Shark Trust has an ever-growing number of passionate supporters. And together we're creating positive change for sharks around the world. Want to join us and help protect sharks around the world? Click here!

Marine Life & Conservation

Book Review: The Sea Lions of Los Islotes



Review of The Sea Lions of Los Islotes – The Jewel of Espiritu Santo Island

Having dived with and filmed these amazing Sea Lions myself many years ago I was delighted to see this new book by Luke Inman. It brought back memories of the most friendly and playful animals in our marine world. Their exuberance and desire for play seems unmatched anywhere else. Luke’s book is a true celebration of the Sea Lion.

The book is well written but not overly heavy on the text. Instead there are short comprehensive paragraphs on their behaviour and lifestyle. This is all supported by plenty of images reflecting Luke’s experiences and relationship with these gregarious animals. It is not often you feel you are watching an animal smile but these do. Constantly. It is with these images Luke shares his love and enthusiasm for the Sea Lions.

In the book Luke mentions the modern day issues faced by the Sea Lions in reference to Climate change, over fishing and Ghost fishing. These are serious factors in the life of any marine animals and must not be ignored or brushed over.

Luke also briefly mentions Sea Lions in captivity for the amusement of human beings. He rightly points out that the animals suffer bad health and die prematurely compared to those in the wild. I would like to add that a Sea Lion in a tank or marine park, performing tricks, is not a Sea Lion at all. It is a low base form of its natural self and should never be captive and imprisoned in this way.

It’s a good book and well worth looking up. Especially as it is getting near Christmas.

About the author

Luke Inman is an award-winning scuba Instructor Trainer, natural history filmmaker, photographer, writer and explorer. His work includes the BBC’s Planet Earth 3, Netflix’s Our Planet and advertising campaigns. Luke is the Owner and Operator of The Dive Gurus — the only PADI 5 Star Instructor Development Centre in La Paz, Baja California Sur, Mexico.

The book

Release date 25 October 2022 | RRP £25 | Paperback | ISBN 978-1-909455-49-8 | 136 pages | 246 x 189 mm

Available now from, online and from retailers.

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Marine Life & Conservation

New feature film tackles Western trade in toxic sharks (Watch Trailer)



“Sharks: In Deep Water is a film to change things,” explains Producer Matt Brierley. The film’s global premiere is 8th Nov 2022 and tickets can be obtained through

Sharks matter. Without the sea’s top predators ocean ecosystems collapse. We are perilously close to creating a tipping point beneath the waves – in many places ocean systems have already collapsed, taking with them people’s livelihoods and their primary source of protein.

This is a topic close to many people’s hearts – but it is also an issue that conjures images of shark finning and Eastern markets. Sharks: In Deep Water tells a new story.

Laws to protect sharks from finning at sea have tragically backfired. Today sharks must have their fins removed on land. That has sparked a global trade in shark meat. As top of the food chain, sharks bioaccumulate human toxicants in concentrations harmful to their health – and ours if we eat them.

Undercover investigation by Sharks: In Deep Water found sharks in Western ports and on menus in high-end UK restaurants. The film conducted DNA analysis of battered fish sold in UK fish and chip shops. The results proved conclusively that Endangered shark is sold under confusing names. The results claimed headlines across the UK.

“Shark livers are also harvested – typically from deep water sharks science knows very little about. Again these are Western market forces not Eastern,” Matt said. “For too long we’ve told shark conservation as a simple story. Sharks are finned at sea by Eastern countries. But the story has moved on and that old narrative is excusing the Western nations who are fishing the shark and selling it – typically – through the Port of Vigo, Spain. The UK and EU are hugely complicit in the greatest underwater extinction event of our time.”

Sharks: In Deep Water is a film that has been designed to educate, inspire and – ultimately – to make a difference. It is uplifting and joyful at times, sad at others, but crucially it is hopeful and an authentic telling of the issues facing sharks present day.

Join Matt, Louise and Samantha and their team as they journey from Morocco to Continental Europe and on into the UK, documenting a trade in sharks closer to home than you ever imagined possible – and finding ways to spark positive change.

Producer Matt Brierley has worked across a suite of Natural History programming including Planet Earth II, Blue Planet II and The Earthshot Prize: Repairing Our Planet.

To watch the film’s trailer, get tickets to the premiere or learn more about the film visit Details of future screenings will also be announced there.

The film team would like to thank Primordial Radio, Bristol Green Capital, Greenpeace, Exeter University, Manchester University, The Daily Mirror, the MCSUK and those who generously supported and publicised their crowdfunding campaigns including Scubaverse.

Producer Matt Brierley is an award-winning Natural History filmmaker who has worked on programmes including Emmy-winning The Serengeti Rules, Attenborough’s Blue Planet II, Planet Earth II and Wild Isles, and Prince Williams’ The Earthshot Prize: Repairing Our Planet. He’s especially passionate about birds, elephants, dinosaurs and, of course, sharks. 

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