Test your knowledge of king of the deep

Advertiser Staff

Betcha didn't know: Sharks attack submarines.

Are you a shark expert? Do you know whether most sharks are dangerous to humans? Take our quiz and find out. Advertiser library photo

Submarines and their towed sonar equipment have been bitten many times by sharks, and so have various types of underwater cables, according to the state Department of Land and Natural Resources. The sharks are believed to be attracted to electromagnetic fields, visual stimuli or sounds produced by these objects.

But you knew that, right? You're in the ocean. Surrounded by it. You know what's going on. You rock! But ... care to quiz yourself or a friend?

Do you think sharks cause more deaths in Hawaiian waters than any other animal?

If you do, pay extra attention to The Advertiser's Shark Week. Fact is, more people drown picking 'opihi than are killed by sharks. Fatal shark bites are extremely rare — and the DLNR Web site goes as far as stating that 'opihi might be considered Hawai'i's most dangerous sea creature.

Check your shark knowledge by taking this quiz, provided by the DLNR Division of Aquatic Resources.

1. Sharks have poor vision. True or False

2. Most sharks are dangerous to people. True or False

3. All sharks are carnivores. True or False

4. Tiger sharks are known to hunt people. True or False

5. All sharks give birth to live young. True or False

Sharks may look fierce, but in Hawai'i, more people are killed every year while picking 'opihi than by shark attacks. Associated Press

7. Most sharks have to keep swimming to breathe. True or False

8. Shark teeth are embedded in sockets in their jaws. True or False

9. Sharks are mostly found in murky waters. True or False

10. You can hit a shark to make it go away. True or False

11. You're more likely to be struck by lightning than bit by a shark in Hawai'i. True or False

12. Sharks may be attracted to any type of human body fluid. True or False

13. Sharks must roll over to bite. True or False

14. Sharks are not too smart. True or False

Answers:

1. False. Sharks can see fairly well if the water is clear. Some sharks are able to see colors.

2. False. Of the more than 380 species of sharks, only about 30 are believed to have been responsible for biting people. And only three (white, tiger and bull) are considered particularly dangerous.

3. True. Although some sharks (like tigers) will feed on almost anything, including dead animals, all sharks are carnivores to some extent. Sharks that feed on plankton are eating small animals, including fish.

4. False. People are not part of any shark's natural diet. As with most sharks, tiger shark bites may often be cases of mistaken identity. Considering how many opportunities tiger sharks have to bite people, the low numbers of bites that actually occur suggest tiger sharks mostly avoid people.

5. False. Some sharks, especially bottom-dwelling species, lay eggs by producing various forms of egg cases, but most sharks are live-bearing.

6. True. Shark skeletons are made entirely of cartilage, not bone.

7. True. Most sharks have to swim to force water over their gills. But many bottom-dwelling species have muscles in their throat that enable them to pump water over their gills while they're not moving.

8. False. Shark teeth are attached to fibrous connective tissue, which is attached to the jaw. There is no direct attachment between the teeth and jaws.

9. False. Sharks are found in any kind of water, regardless of how clear or murky it might be.

10. True. Sharks are vulnerable in some areas, like the eyes, snout, and gills, and hitting a shark there may make it leave. On the other hand, it could make the shark more aggressive. Studies have shown that much more often than not, hitting a shark will have the desired effect, but it should be a last resort. Use an available object as a weapon if you can.

11. False. Sorry, it's a trick question. Although that's true for most of the rest of the world, Hawai'i has very few electrical storms and people are almost never hit by lightning. But you are more likely to be injured by a falling coconut than by a shark.

12. True. But the operative word is "may." Blood will certainly attract the attention of a shark. Other body fluids, such as urine or sweat, can probably be detected by sharks. But whether sharks find them "attractive" is unknown.

13. False. Most sharks take prey in an upright and level body position. The loose attachment of a shark's jaws to its skull makes it possible for sharks to bite in any position.

14. False. Some sharks have brains that are larger than those of birds and mammals of similar sizes and have been reported to learn at about the same rate as some birds and mammals. They have been trained to swim mazes and perform other tasks for food. The megamouth shark, on the other hand, has a very small brain (about half the size of an adult human thumb), so it's hard to speculate on its capacity for learning.

Grading scale: 0-2 correct — Congrats, you must be from the Midwest. 3-5 — You've attained hammerhead status. 6-8 — You are the tiger shark of trivia. 9-11 — Great whites, beware! 12-14 — The Discovery Channel needs you!

For more information, see www.hawaii.gov/dlnr/dar/sharks/index.html.