SCIENCE

Frilled sharks are rarely seen denizens of the deep that resemble their dinosaur-era ancestors. (National Geographic News)

Use our resources to learn more about some dinosaur-era “Sea Monsters.”

Teachers, scroll down for a coloring page and a quick list of key resources in our Teachers’ Toolkit.

Discussion Ideas

• Read our activity “Sea Monsters: Unpack the Evidence.” Review its central questions and concepts: What is evidence? What is inference?
  • Evidence is data that can be measured, observed, examined, and analyzed to support a conclusion.
  • An inference is an explanation derived by reasoning.

• Take a look at the frilled shark in the photo below, then adapt the questions in the “Unpack the Evidence” activity to the new specimen of frilled shark caught off the coast of southeastern Australia.

• Offer some evidence about the frilled shark, based on the photo and the Nat Geo News article.
  • Some pieces of evidence based on the photo might include:
    • The frilled shark has a long, thin body.
    • The frilled shark has rows of sharp, backward-facing teeth.
    • The frilled shark does not have a triangle-shaped dorsal fin rising from its back, like many other sharks.
    • The frilled shark does not have a fan-shaped tail, like many other sharks.
  • Some pieces of evidence based on the article might include:
    • A frilled shark was caught in the resort town of Lake Entrance, Victoria, Australia.
    • The Australian frilled shark was about 2 meters (6 feet) long.
    • The frilled shark is rarely spotted and even more rarely caught.
    • The frilled shark lives in the mid-to-deep ocean.

• Based on the evidence you’ve presented about the frilled shark, make some inferences.
  • Why do you think the shark has backward-facing teeth?
    • Dozens of rows of sharp, backward-facing teeth make it difficult for prey to escape. A quote in the article makes this a good inference: “[O]nce you’re in that mouth, you’re not coming out,” said Simon Boag of Australia’s South East Trawl Fishing Association.
  • Why do you think the fish is called the frilled shark?
    • The “frills” are its long gill slits, which stretch across the fish’s throat.
    • Another possible inference might be that the frilled shark was named for its frills of teeth. This is a reasonable inference based on the evidence available (photo and article), but acquiring more evidence would prove this inference to be wrong.
  • Do you think the frilled shark is indigenous to Australia?
    • It is. The fact that the shark is rarely spotted, and many of the spottings have happened in Australia make this a good inference. Frilled sharks are actually thought to be indigenous in pockets of coastal areas throughout the Atlantic and Pacific Oceans.
  • Do you think the frilled shark is an endangered species?
    • It isn’t. The IUCN lists the frilled shark as “near threatened,” which is not an endangered category. There just seem to be a naturally small number of the fish, possibly—here’s an inference—due to their long gestation period and few offspring. (Scientists think the frilled shark may have the longest gestation period of any vertebrate—three-and-a-half years!)
    • Another possible inference might be that the frilled shark is endangered because it’s such an unusual thing to catch. This is a reasonable conclusion based on the evidence available (photo and article), but acquiring more evidence would prove this inference to be wrong.

• How can you gather more evidence to make more educated, accurate inferences about the frilled shark?
  • Read about it! The “frilled shark” article in Wikipedia has that green + symbol in the upper right corner, which means it’s a “good article.” This is a great place to start.
  • The library is always your best resource, and librarians are your second-best. Find your local public library here.
  • Look at images of frilled sharks in books or on film. National Geographic can get you started with this great photo gallery! And here’s what Shark Week has to say about the frilled shark!
  • Visit an aquarium (this is the best!) or natural history museum. Although no aquarium has a live frilled shark, staff there can definitely offer some great information, and point you in the right direction. Find a zoo or aquarium here, and here’s a list of some natural history museums.
  • Ask an expert! Talk to people who know what they’re talking about. Fishermen and ichthyologists—scientists who study fish—are usually happy to talk about their favorite subject. You can start getting familiar with academic literature by simply doing a search for “frilled shark” in Google Scholar, and contact your local Fish & Wildlife office to learn more about fishing.

TEACHERS’ TOOLKIT

Nat Geo: Rare Shark That Inspired Sea Monster Myths Is Caught

Nat Geo: Unpack the Evidence: What are evidence and inference?

Wikipedia: Featured articles (best of the best)

U.S. Census: Find a Public Library

Association of Zoos and Aquariums: Find an AZA-Accredited Zoo or Aquarium

Google Scholar

U.S. Fish & Wildlife Service: Fish and Wildlife in Your State