How Shark Species Work from HowStuffWorks

How Bull Sharks Work
Ganges shark. Zambezi shark. Ground shark, shovelnose, freshwater whaler, swan river whaler or slipway grey. No matter what name you call it, the bull shark can be found all over the world. And not just in the ocean: It dwells in lakes and rivers, too. The International Shark Attack File puts the bull shark at No. 3 on the list of unprovoked attacks on humans, with 77 incidents and 25 fatalities as of April 2008. Get the M.O. on the bull shark, from what it eats, how it reproduces, how it survives in fresh water and, of course, what makes it so deadly.

How the Great White Shark Works
Let’s face it. The great white is often typecast to represent everything angry and fierce that lies in the murky ocean waters. But ponder these quick facts you might not know about the notorious great white. First, great whites don’t chew their food. (Prompting the question: How do they eat?) Second, the strength of a shark bite is about 1 ton per square inch. And consider this third intimidating fact: While in the womb, great white shark embryos feast on unfertilized eggs, in a cannibalistic practice known as oophagy.

How Tiger Sharks Work
Identified by biologists in 1822, Galeocerdo cuvier has a pretty cool nickname. While most of us just know it as a tiger shark, its less glamorous moniker is "garbage can of the sea." Besides feasting on seals and turtles, tiger sharks have been known to eat tires, nails, beer bottles and even small animals you’d find on the family farm. Read more interesting and strange facts about this second deadliest shark after the great white.

How Nurse Sharks Work
Nurse shark: The name conjures images of a big-screen cartoon character whose job it is to take care of its saltwater brethren of the ocean. Well, that's not exactly accurate. Sometimes called “slacker of the sea,” the nurse shark is a rather mellow, lazy breed. Averaging 7 to 9 feet in length and with varying colors, these guys would rather stay put and let the food come to them than chase down their dinner. So how do they survive? And how do we identify them? Find out in this article.

How Hammerhead Sharks Work
While there are nine different classifications of hammerhead sharks, only four are common: the great hammerhead, scalloped hammerhead, smooth hammerhead and bonnethead. Of these four, all but the bonnethead are considered to be dangerous to humans. Don’t worry too much, though -- there have only been 38 recorded hammerhead attacks on humans since 1580, only 16 of which were unprovoked. Plus, no one has ever been killed by a hammerhead. But the question on everyone’s mind after viewing one of these guys at an aquarium? Why do these sharks have such oddly shaped heads?

How Angel Sharks Work
Angel shark seems like an oxymoronic term for a creature we typically deem as vicious. And just as strange as their name? The fact that they don’t really look too shark-like at all. In fact, they're often mistaken for rays or skates, given their flattened appearance. But even if they're not as ferocious-looking as other sharks, don't underestimate them. Their sharp teeth and tenacious bite have earned them a more sinister nickname: sand devil.

How Pygmy Sharks Work
It’s an age-old (and often tongue-in-cheek) question: Does size matter? Perhaps if you are part of the sea’s taxonomy, the answer is yes. Compared the great white (averaging 20 feet in length) the pygmy – averaging 7 to 8 inches long – was accurately named. Albeit small, these guys have a few tricks to keep them safe from the jaws of their predators. So why are pygmy sharks rarely seen and not widely studied? Where do they swim, what do they eat and are they a threat to humans? Read on to find out …

How Whale Sharks Work
When many of us think about the biggest shark in the ocean, we often conjure thoughts of the largest jaws. (Does a certain movie poster come to mind?) But the much-feared, 20-foot-long great white has nothing on the whale shark. These guys dwarf any fish in the sea and can grow to be up to 60 feet long. To put this size into perspective, that’s about 20 feet longer than a school bus. So while the whale shark is obviously hard to miss, it is extremely difficult to capture one for researchers to study and there is a lot about this behemoth shark that we still don’t know.