Sharks have been swimming the planet's waterways since dinosaurs roamed the earth, and they still hold a fascination for humans.

"That word, 'shark', just gets the hairs on the back of your neck standing up," said shark expert Nigel Marven, one of the hosts of Discovery Channel's annual celebration of sharks. "We love our monsters."

For the 17th year, the cable channel offers a weeklong, closeup view of the creatures whose reputation is based on both fiction and fear. Beginning Sunday at 8 p.m. with two episodes, and continuing through Friday, sharks of all stripes star in seven new hour-long specials.

"The fearmonger movies really play up the fear, but a lot of people don't know much about sharks at all," said Abby Greensfelder, Discovery's senior vice-president of programming and development. "What has worked well for us is to explore the science of sharks, not just the blood-lust animals. They're this kind of iconic animal, incredibly intelligent and, in many cases, mysterious."

Greensfelder said the "Shark Week" ratings are typically 60 percent to 100 percent above the network's average and that the weeklong event has become a summertime favorite.

Even for those participating in the shows, the mystique of sharks is alluring.

"When you're in a shark cage , you cannot help but hear that music [the theme from the movie 'Jaws']," Marven said. "But if they were out to get us, we couldn't go in the water anyway. They can detect body electricity, they see and hear us swimming. When you see a Great White turn its bluey-black eye to you, it is unbelievable. You're in awe of them."

Mike deGruy hosts two of this year's episodes. "Their reputation is primitive but they have spent hundreds of millions of years evolving into these torpedoes," he said. "They are so beautifully formed in the water, you have to appreciate them and how good they are at what they do."

DeGruy said he is amazed that "Shark Week" remains so popular. "That tells me people are interested in these creatures, that we've gone away from the 'Jaws' mentality to, my gosh, we're losing these things," he said. "Talk to any scientist doing population studies and they'll tell you the sharks are vanishing.

That people would cut off a shark's fins for soup and throw a live, finless shark back, that's horrendous. I hope people can learn something from these programs about these animals that they didn't know before."

One of deGruy's segments, called "Size Matters," focuses on what he calls "the little guys."

"Most programs that celebrate sharks deal with the more conventional-looking animals, but in California where I live, there are a lot of smaller ones and I would even call them cute," he said.

Some of the sharks spotlighted are no more than a foot long. "With all the diversity and competition, if you're a shark, you have to do something special to survive," deGruy said. "They've adapted to the environment by going deep and running away from the predators."

DeGruy said there are more than 400 types of sharks and only a handful are dangerous to man.

One of those is featured in Marven's segment on the bull shark, which he calls the deadliest of all.

"It is the only big shark that can go into fresh water, and cope with the great changes of salt to fresh water," he said. "It eats anything and if we get in the way where it can't see properly, it can have a go at us even if human flesh isn't on the menu."

The film captured a sudden attack on shark expert Erich Ritter. "We take calculated risks every time we're in the water," said Marven, who interviews Ritter in the segment, discussing the attack and what went wrong.

Both deGruy and Marven believe sharks will continue to lure filmmakers and viewers.

"Of all the varieties of sharks that have been covered by TV, the surface has only been scratched," said deGruy. "A lot of them haven't ever been filmed. I don't see us running out of material anytime soon."

Shark Week On Discovery

Seven new hour-long programs explore a wide array of sharks and situations:

* Sunday: "Primal Scream" at 8 p.m. and "Tiger Shark Attack" at 9 p.m.

* Monday: Monster House: Shark House" at 8 p.m.

* Tuesday: "Great White Shark Uncaged" at 8 p.m.

* Wednesday: "Dive to Shark Volcano" at 8 p.m.

* Thursday: "Bull Shark: World's Deadliest Shark" at 8 p.m.

* Friday: "Sharks: Size Matters" at 8 p.m.