Photo: Awashima Marine Park/Getty Images
One might think that such a long-bodied fish like this must related to an eel, an oarfish or some kind of mythical sea serpent but nope, it's definitely a shark! Frilled sharks are named for their gill slits, which have a tendency to extend and "frill" out. Because they typically live at depths below 600 meters, it's rare to see them alive near the surface. The image above, taken in Awashima Marine Park, shows a 1.6-meter-long frilled shark that was found by a fisherman in the nearby bay of Numazu, Japan in 2007.
Photo: name/Getty Images
While these little guys might appear oddly cute and endearing in the images above, the reason these small dogfish-type sharks are called "cookiecutters" has little to do with baking holiday cookies at grandma's and a lot to do with their grotesque feeding habits. Using their wide, strong jaws, these parasites bite circular chunks of flesh out of their unlucky victims. The resulting wound is so neat and cleanly cut that it's almost as if a cookie cutter was used.
Photo: Chris Gotschalk/Wikimedia
This creature may appear terrifying, but no worries — basking sharks are slow-moving gentle giants that use their gaping mouths to passively collect and filter zooplankton and other small marine creatures. One fascinating behavior found in basking sharks is breaching, which means jumping entirely out of the water like a dolphin or a whale. While scientists aren't exactly sure why they do this, some speculate it's to dislodge parasites attached to their bodies (cue glare towards the cookiecutter sharks).
Photo: Toru Yamanaka/Getty Images
There are few images of living megamouth sharks simply because only 59 specimens of this rare deepwater species have been spotted or caught since their initial discovery in 1976. One thing scientists do know about these filter feeders is that they possess luminous photopores around their jaw — a feature that is most likely used to attract plankton and other prey.
Photo: Dianne Bray/Museum Victoria/Wikimedia
These rare sharks are the last living species of the Mitsukurinidae family, an ancient lineage of sharks that dates back to 125 million years ago. Because they still retain some of their family's primitive traits, they're considered to be living fossils. Like many deep-sea creatures, goblin sharks are occasionally pulled in as bycatch by deepwater fisheries, but there is still so much to learn about them (well, aside from the fact that they're excellent at inducing nightmares).
Photo: Richard Ling/Wikimedia
This bottom-dwelling family of sharks contains 12 different species that typically live in the shallow, warm waters of the Pacific and Indian oceans. Thanks to the colorful carpet-like patterns adorning their bodies, these sharks are great at camoflauging themselves on the ocean floor. The name "wobbegong" is derived from the Australian Aboriginal word meaning "shaggy beard" — an obvious reference to the growths surrounding the shark's mouth.
Photo: Gary J. Wood/Wikimedia
Ah, yes, the faithful hammerhead shark! Of all the "weird" sharks on this beautiful planet, this is the one that most easily comes to mind. There are several different species within this family, including the great hammerhead (above), the scalloped hammerhead and the winghead shark. Their most distinctive feature and namesake — the flat, hammer-shaped head with eyes propped up on either end — is believed to enhance their senses. Several of these species are listed as endangered or vulnerable due to overfishing and the demand for shark fin soup in countries where it is considered a delicacy.
Photo: name/Getty Images
The sawshark is known for its distinct saw-shaped snout, and it most definitely should not be confused with the sawfish (which actually happens to be a type of ray). One way to distinguish a sawfish and a sawshark is to note the position of their gill openings. A sawshark's gills are located on either lateral side of its body (like other sharks), while sawfish gills are located on its underside (like other rays).
Photo: Nick Long/Wikimedia
With their flat bodies and broad, wing-like pectoral fins, it might be tempting to classify these bottom-dwelling creatures as rays based simply on their looks, but that would be a mistake for the same reason why a sawshark and a sawfish are different (explained above).
Sure, this ancient shark species may be extinct, but the legendary Cenzoic predator still deserves a place on this list considering it once ruled Earth's seas with its massive, fearsome jaws. Often imagined as a larger version of the great white shark, the megalodon is considered by many scientists to be the most powerful predator in vertebrate history.
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