Walking and Epaulette Sharks: Intriguing Fish With Muscular Fins

Updated on February 23, 2020
AliciaC profile image

Linda Crampton is a writer and teacher with an honors degree in biology. She loves to study nature and write about living things.

An epaulette shark (Hemiscyllium ocellatum)
An epaulette shark (Hemiscyllium ocellatum) | Source

Unusual and Interesting Fish

Walking sharks are unusual fish with an elongated shape and muscular fins on the lower part of their body. The fins enable the fish to "walk" along the ocean floor. In the case of at least one species, they enable the animal to move over land as well. The body of walking sharks is decorated with spots, blotches, or stripes. The animals belong to the genus Hemiscyllium. Researchers have recently announced the existence of four new species of walking sharks, bringing the total number to nine.

Though most people probably think of sharks as fierce and fast-moving predators that are occasionally dangerous for humans, many more benign species (from our point of view) exist. Walking sharks are one example. When the fish are "walking", the front part of their body resembles that of a moving salamander. They aren't believed to be closely related to the amphibian, however. In this article, I highlight the epaulette shark, which is the best known species in its genus and the one known to leave the water and travel over land.

The genus Hemiscyllium belongs to the family Hemiscylliidae. This family is also known as the longtail carpet shark family. Carpet sharks (or carpetsharks) are named for the fact that the pattern on their body surface resembles that of an ornate carpet.

Fins of a typical shark
Fins of a typical shark | Source

Fins and Features of a Walking Shark

The illustration above shows the type of shark that is probably most familiar for many people. The fish has:

  • two dorsal fins on its back
  • a pectoral fin on each side near the gills
  • a pelvic fin on each side underneath the body and towards the rear end
  • an unpaired anal fin behind the pelvic fins
  • a caudal fin, which forms the tail; the upper lobe of this fin is larger than the bottom one

The body shape of a walking shark is different from that of the torpedo-shaped animal shown above. A walking shark is long and slender. It has a long "tail" or caudal peduncle behind the last dorsal fin. The caudal peduncle is the narrow area in front of the caudal fin of a fish.

Walking sharks have the same fins as the classical shark. The pectoral and pelvic fins are muscular and paddle-shaped, however. In addition, the caudal fin has only one lobe. The dorsal fins are located far back on the body and the anal fin is located near the caudal one.

The new announcement that nine species of walking sharks exist is based on a twelve-year study. Researchers suspect that more fish belonging to the genus Hemiscyllium will be discovered. The known species live in warm water on the coast of Australia, New Guinea, and Indonesia.

The Epaulette Shark

The epaulette shark lives in water around Australia and New Guinea. Unconfirmed reports suggest that it also lives in other areas nearby. The fish is light grey or brown in colour and has darker spots. Its name comes from a large black spot encircled with white that is located on each side of its body just behind the pectoral fin. The spot reminded earlier biologists of military epaulettes. It's thought that it may act as a distraction for predators. It looks like a large eye from a distance. It's easy to imagine that the "eye" belongs to a bigger animal than the shark. The animal's real eye is much smaller.

The adult fish is generally no longer than a metre. It has the long caudal peduncle that is typical of its genus. Its snout is noticeably rounded and has barbels at its tip. Barbels are fleshy extensions that are believed to act as sense organs and to play a role in detecting food.

An opening called a spiracle is located under and behind each eye. The spiracle absorbs water and sends it to the gills. The blood vessels in the gills absorb oxygen from the water. They also send carbon dioxide waste made by the shark's body into the water. The water then returns to the ocean through the gill slits on the side of the animal.

An epaulette shark in a public aquarium
An epaulette shark in a public aquarium | Source

Surviving on Land

The epaulette shark is usually found in shallow water. It swims through the water and walks on the ocean floor and on land. Though walking sharks don't walk in the way that we do, their muscular fins have a wide range of motion and are a useful aid to propulsion on a solid surface. The walking movement of the epaulette shark is thought to resemble that of the first four-legged animals that appeared on land.

The shark can survive for an amazingly long time with a low oxygen level in its body. This means that it can exploit habitats that other fish are unable to reach. It can reportedly stay out of water for up to an hour. Some researchers claim that the time is even longer. The features that enable the fish to survive under these conditions are still being studied. It seems to have multiple adaptations that enable it to live on land, including the ones listed below.

  • The breathing rate decreases.
  • The heart rate also decreases.
  • Blood flow to the heart increases.
  • Blood vessels going to some parts of the brain dilate, allowing more oxygen to reach the organ. Blood flow to less vital areas of the brain is decreased, however.
  • Nerves continue to function in a low-oxygen environment.

On land, the fish sometimes dampens its body as it travels through tide pools and into puddles in the coral reef. It also moves over dry sand, however, which would seem to be a less hospitable environment. Its survival abilities are impressive.

Diet of an Epaulette Shark

Epaulette sharks are mainly bottom feeders and feed mostly on invertebrates, such as crabs, shrimp, and polychaete worms. They also eat small fish, including ones trapped in tide pools. By coming onto land as well as feeding in the ocean, epaulette sharks are able to find food items that are unavailable to most other fish. They sometimes chew their prey before swallowing it, which is an unusual behaviour for a shark.

Researchers have discovered that the sharks are active at any time during the day or night but are most active during crepuscular (dawn or dusk) conditions. They detect their prey by using their sense of smell or by detecting the weak electric currents produced by the muscles of the animals. Sharks have electroreceptors that contain tubes filled with jelly and connect to the outer world via pores in the animal's skin. The receptors are known as the ampullae of Lorenzini.

An epaulette shark on a beach
An epaulette shark on a beach | Source

Behaviour on Land

It might be thought that by coming onto land the epaulette sharks expose themselves to terrestrial predators. If this is the case, it doesn't seem to be hurting their population size. It's known that the sharks sometimes come into conflict with other fish when they are on land. The epaulette shark is not the only species to leave the ocean and survive. Some species of moray eels occasionally come onto land, for example.

Epaulette sharks sometimes travel over sand to reach desirable feeding areas. They may pause and become stationary on the sand for a while. This appears to be the case for the animal in the photo above. The fish face the prevailing air current when they pause. The behaviour is known as rheotaxis. It's not known for certain why epaulette sharks perform this behaviour. Suggestions include improvement of respiration or a way to detect predators.

Egg and fetus of Scyliorhinus canicula (a type of catshark)
Egg and fetus of Scyliorhinus canicula (a type of catshark) | Source

The beautiful photo above shows a typical egg case of a shark and the developing animal inside it. Epaulette shark egg cases and the moving youngsters inside them are shown in the video below.

Reproduction

In their natural environment, epaulette sharks breed from July or August to December. Fertilization is internal, as in other sharks. The male inserts sperm into the female's body with his claspers. A clasper is an elongated structure under each pelvic fin. It can be seen in the illustration of shark fins shown above. Sperm leaves the male's body, travels along a groove in a clasper, and enters the female's cloaca.

Epaulette sharks lay eggs and are therefore said to be oviparous. Two eggs are generally laid for every mating incident, which sometimes happens as often as every two weeks. The female ignores the eggs after they are released. She may lay as many as fifty eggs in total during the breeding season, though there is some debate about this number.

Each egg is enclosed in a case that is sometimes known as a mermaid's purse. Fibrous extensions on the case help to attach it to the surroundings. Gestation lasts for around 120 days. The young sharks that emerge from the cases are decorated with black and white bands. These break up into spots as the fish mature. The animals may live for twenty years or more.

Population Status

Thankfully, the epaulette shark population appears to be doing well. The fish is not of much interest to commercial fisheries. It's captured for the aquarium trade, however, and is sometimes collected by local people who need food.

Some people pick up the fish for amusement when they find it. This is potentially harmful for two reasons. The fish is sometimes injured when it's handled. In addition, it's not advisable to pick up any shark, no matter how docile it seems to be. Although the epaulette shark is often said to be harmless to humans, it may bite when it's frightened. In Australia, some of the animal's habitat is located in marine reserves, which is probably helpful for its numbers.

The IUCN (International Union for Conservation of Nature) classifies the shark in its Least Concern category and says that its population is stable. The assessment is based on data obtained in 2015. It's good to know that the fish seems to be safe at the moment.

The epaulette shark has some fascinating features. More research is needed to clarify some of the facts about the fish and to solve the puzzles linked to its life. Hopefully more information about the animal and more discoveries about walking sharks in general will soon appear.

References

Questions & Answers

    © 2020 Linda Crampton

    Comments

      0 of 8192 characters used
      Post Comment
      • AliciaC profile imageAUTHOR

        Linda Crampton 

        6 weeks ago from British Columbia, Canada

        Thank you, Paula. I appreciate your visit and comment very much.

      • fpherj48 profile image

        Paula 

        6 weeks ago from UpstateWestern,New York

        Linda/Alicia.....Well, my dear, looks like you are bound & determined to make all your readers, highly-informed/knowledgeable individuals! Thanks for this fascinating read. Your research and efforts are much appreciated.

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        6 weeks ago from British Columbia, Canada

        Hi, Genna. I think all sharks are interesting, though I agree that the smaller species look less intimidating! Thank you for the visit.

      • Genna East profile image

        Genna East 

        6 weeks ago from Massachusetts, USA

        Hi Linda. the smaller variety of these critters look so cute. But sharks still scare me -- walking or not. :-) This is such an interesting article; it's amazing to learn how various species adapt in order to survive oin their environment.

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        7 weeks ago from British Columbia, Canada

        Hi, Flourish. The fish do have an interesting method of reproduction! Thank you for the comment.

      • FlourishAnyway profile image

        FlourishAnyway 

        7 weeks ago from USA

        Very interesting and the name “mermaid purse” is so cute. Laying eggs every two weeks during breeding season sounds exhausting! But I guess since it’s only two at a time and you don’t have to raise them that may me okay.

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        2 months ago from British Columbia, Canada

        Hi, Kari. I'd like to visit Cape Cod. It has always sounded like an interesting place to me.

      • k@ri profile image

        Kari Poulsen 

        2 months ago from Ohio

        Thanks for all the good information! I think I used to see "mermaid purses" on the beach while vacationing in Cape Cod.

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        2 months ago from British Columbia, Canada

        Thank you very much, Denise. Blessings to you as well.

      • PAINTDRIPS profile image

        Denise McGill 

        2 months ago from Fresno CA

        I believe I've heard of this shark before but didn't pay much attention. This is great information. Thanks.

        Blessings,

        Denise

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        2 months ago from British Columbia, Canada

        Hi, Bill. I think the shark is a fascinating creature, too, as well as any other fish that can survive on land. Thank you very much for the visit and the comment.

      • bdegiulio profile image

        Bill De Giulio 

        2 months ago from Massachusetts

        What a fascinating creature, Linda. I was remotely aware of some fish and shark species that could travel on land, but have never heard of the epaulette shark. You continue to amaze me by introducing us to these amazing creature.

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        2 months ago from British Columbia, Canada

        Thank you very much for the kind comment, Dora. I appreciate your visit.

      • MsDora profile image

        Dora Weithers 

        2 months ago from The Caribbean

        Congratulations on your 2019 HubAward! Your articles always inform and educate us. As usual, it is fascinating to know about these different kinds of sharks and their habits.

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        2 months ago from British Columbia, Canada

        Hi, Peggy. A fish walking on land is an interesting thought! Sharks have some surprising features. They're not as simple as some people believe.

      • Peggy W profile image

        Peggy Woods 

        2 months ago from Houston, Texas

        Thanks for introducing me to another interesting sea creature, Linda. It must be amazing to see such a creature walking on land!

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        2 months ago from British Columbia, Canada

        Hi, Nithya. I think the sharks are amazing animals. I hope researchers learn more about them.

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        2 months ago from British Columbia, Canada

        Hi, Rachelle. Thanks for the comment. I read lots of biology articles and enjoy exploring nature in real life. I often get ideas for writing topics when I do this.

      • Vellur profile image

        Nithya Venkat 

        2 months ago from Dubai

        I did not know about the epaulette shark until I read this article. The photos are amazing. The adaptations of these sharks to survive out of the water for nearly an hour must be amazing. It is great that the population of these sharks is stable.

      • Rachelle Williams profile image

        Rachelle Williams 

        2 months ago from Tempe, AZ

        A shark that leaves the water and travels to land areas... First and foremost, where in the world did you first learn about these creatures? Second, thank you for introducing me to these little baby monsters, because I'd never heard of them before and third, please let's hope the SyFy channel doesn't catch wind of them....

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        2 months ago from British Columbia, Canada

        Hi, Mary. I think they're interesting fish, too. They are kept in some commercial aquariums, though I don't know how much room they have to walk in their tanks in these facilities. I hope they have enough space to be reasonably comfortable.

      • aesta1 profile image

        Mary Norton 

        2 months ago from Ontario, Canada

        I have not seen these sharks. I have seen moray eels but not these. They are quite interesting. I would love to see one walk.

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        2 months ago from British Columbia, Canada

        Thank you very much, Suchismita. I appreciate your visit.

      • Suchismita pradhan profile image

        Suchismita Pradhan 

        2 months ago from India

        Loads of information on walking shark.A well researched article.Keep writing.

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        2 months ago from British Columbia, Canada

        Thanks for the visit and the comment, Heidi. I agree with you. I think a lot of people may not realize how many types of sharks exist. I hope you have a good week.

      • heidithorne profile image

        Heidi Thorne 

        2 months ago from Chicago Area

        Another cool animal friend indeed! I think people have no idea of the variety of sharks out there, big and small. Thank Jaws for that. ;)

        I can't remember if I saw one when I visited our Shedd Aquarium. But it would be cool to see.

        Happy Monday!

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        2 months ago from British Columbia, Canada

        Thank you very much for the kind comment, Linda.

      • lindacee profile image

        Linda Chechar 

        2 months ago from Arizona

        That epaulette shark is quite remarkable. I've never heard of these species. It is amazing that they can walk on the ocean floor, in shallow water and on land. I always enjoy your articles!

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        2 months ago from British Columbia, Canada

        Thank you very much, Chuck. The shark has some fascinating features that are interesting to explore.

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        2 months ago from British Columbia, Canada

        Thanks for the comment, Liz. I think the way in which the fish move is very interesting. Life in the ocean seems to hold many surprises for us.

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        2 months ago from British Columbia, Canada

        Thanks for the comment, Pamela. I think that sharks are a fascinating group of animals that are worth exploring.

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        2 months ago from British Columbia, Canada

        I agree, Raymond! It is great to hear about a species that is doing well. The animal is extraordinary, as you say.

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        2 months ago from British Columbia, Canada

        Hi, Manatita. I'm not sure what sound you're referring to. Life on Earth is certainly awesome. There's a lot of beauty to be found here. Thank you for the comment.

      • Chuck profile image

        Chuck Nugent 

        2 months ago from Tucson, Arizona

        This is a great Hub about a fascinating creature. I had never heard of this type of shark before and enjoyed reading your article. You did a great job of researching and writing this.

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        2 months ago from British Columbia, Canada

        Hi, Louise. I think the ocean is fascinating to explore. As you say, it contains some lovely creatures!

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        2 months ago from British Columbia, Canada

        Hi, Bushra. I think it's a fascinating animal, too!

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        2 months ago from British Columbia, Canada

        Hi, Devika. Thanks for the comment. The epaulette shark has some very interesting features. I think it's worth studying.

      • Eurofile profile image

        Liz Westwood 

        2 months ago from UK

        This is a very detailed and informative article. I have learnt a lot from reading it. I had no idea about epaulette sharks before. Thank you for enlightening me about their existence. I shall keep an eye out for them in future when visiting aquariums. I was especially amazed at their ability to 'walk' and survive for short periods out of the water.

      • Pamela99 profile image

        Pamela Oglesby 

        2 months ago from Sunny Florida

        I have never heard of a walking shark before and I didnot know there were so many types of sharks. I found the epaulette shark to be quite interesting. Thanks a wealth of new informaiton.

      • raymondphilippe profile image

        Raymond Philippe 

        2 months ago from The Netherlands

        Isn’t it great, for a change, to read a particular species is doing well instead of disappearing from the earth’s surface. What an extraordinary shark.

      • manatita44 profile image

        manatita44 

        2 months ago from london

        Fascinating! This sound that I hear in the videos, is it their breathing? They leave me in awe and all the more reverential to the Higher Intelligence, which some call God. We live with so much beauty! Just a little more in human hearts and we will enjoy an amazing universe. Gratitude.

      • Coffeequeeen profile image

        Louise Powles 

        2 months ago from Norfolk, England

        I've never seen a shark like this before, but I think it's really cute. It's amazing the amount of lovely creatures in the ocean.

      • Bushra Iqbal profile image

        Aishatu Ali 

        2 months ago from Rabwah, Pakistan

        What a fascinating animal! Thank you for posting this article here.

      • profile image

        Devika Primic 

        2 months ago

        Hi Linda an amazing write up here on this fish. I had no idea of it and somehow you got to it and informed me of such an interesting and fascinating . Facts are intriguing and a thorough research into the life of this fish tells me you know it better than I

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        2 months ago from British Columbia, Canada

        Thank you for the visit and the comment, Eman.

      • Emmy ali profile image

        Eman Abdallah Kamel 

        2 months ago from Egypt

        It is really an unusual and interesting fish. I enjoyed reading this educational article.

      • AliciaC profile imageAUTHOR

        Linda Crampton 

        2 months ago from British Columbia, Canada

        Thank you, Umesh. I appreciate the comment.

      • bhattuc profile image

        Umesh Chandra Bhatt 

        2 months ago from Kharghar, Navi Mumbai, India

        Well researched and exhaustive. Nice work. Thanks.

      working

      This website uses cookies

      As a user in the EEA, your approval is needed on a few things. To provide a better website experience, owlcation.com uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

      For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at: https://maven.io/company/pages/privacy

      Show Details
      Necessary
      HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
      LoginThis is necessary to sign in to the HubPages Service.
      Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
      AkismetThis is used to detect comment spam. (Privacy Policy)
      HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
      HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
      Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
      CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
      Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the googleapis.com or gstatic.com domains, for performance and efficiency reasons. (Privacy Policy)
      Features
      Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
      Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
      Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
      Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
      Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
      VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
      PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
      Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
      MavenThis supports the Maven widget and search functionality. (Privacy Policy)
      Marketing
      Google AdSenseThis is an ad network. (Privacy Policy)
      Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
      Index ExchangeThis is an ad network. (Privacy Policy)
      SovrnThis is an ad network. (Privacy Policy)
      Facebook AdsThis is an ad network. (Privacy Policy)
      Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
      AppNexusThis is an ad network. (Privacy Policy)
      OpenxThis is an ad network. (Privacy Policy)
      Rubicon ProjectThis is an ad network. (Privacy Policy)
      TripleLiftThis is an ad network. (Privacy Policy)
      Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
      Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
      Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
      Statistics
      Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
      ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
      Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)
      ClickscoThis is a data management platform studying reader behavior (Privacy Policy)