Whether it's public speaking, violence or voices coming from the closet, there is always something out there waiting to scare you. And fear, it seems, doesn't discriminate by age.

With the 37,000-plus enrollment at the UA, one might never know that the 21-year-old next to you in class or behind you in line at the Student Union Memorial Center is still scared of the dark.

Stephen King's "It" had its role in making Mike Landis, a physiological sciences junior, averse to clowns.

"Clowns," said Landis about his childhood, shivering. "I hated clowns. I had a scary-ass clown picture in my house, and I would always see it because it was outside my room."

To this day, Landis shies away from clowns at the circus. When he sees one, he still tells himself it isn't going to hurt him.

"I have some friends that are scared of the dark still," said Landis. "They always have to have a light on, especially if they're sleeping. If they're sleeping, they'll check the doors 10 times ... even if someone's with them in the room. They have to have the light on."

"Fear is a built-in emotional reaction that's largely adaptive," said Jeff Greenberg, a professor of psychology at the UA. "When we're afraid, it sends a 'flight or fight' response."

While the adaptive nature of fear may protect us from danger or cause us to err on the side of caution, it also makes people do things like hide under the covers when they think someone is under the bed or scream when a friend jumps out of the closet.

"When your brain perceives a threat, that stimulates activity in the limbic system, which leads to the release of hormones that create physiological arousal," said Greenberg. "When anyone is afraid, their heart rate increases, which increases the flow of blood."

Greenberg said students often become anxious over exams, fearing the score reflects their overall intelligence. Then there is the dating scene, where individuals become concerned with their acceptance and the potential direction of the relationship.

"I don't like haunted houses at all," said vocal music education junior Angela Carrasco. "I really don't. I get really freaked out, even though I know it's fake."

Carrasco said she also can't watch horror movies, even in the daytime.

"I'll run into the bathroom and start screaming," she explained. "My friends are trying to introduce me to children's Halloween stories so I can start getting used to scary movies."

Juan Brandenburg, a computer and electrical engineering junior who grew up in Culiacan, Mexico, said that from the ages of 8 to 10, he was freaked out about the chupacabra, or "goat-sucker," which is a popular Mexican spook.

"Even the news, the TV news, they would show: 'These farmers were attacked by the chupacabra,'" said Brandenburg. "They would show goats with big holes in their neck with the blood sucked out. It was on the news. It was everywhere. It was like a phenomenon."

Brandenburg said his brother was so scared of the chupacabra that he would cry himself to sleep, a situation not helped when Brandenburg put a dead animal fetus under the bed for his brother to find and draw superstitious conclusions.

Yasaman Vafaei, a pre-pharmacy freshman, said she fears not being successful.

Krystal Francis, a hairdresser at Great Clips in the Student Union Memorial Center, said some students are afraid of getting a jacked-up hair cut because they mistakenly assume the hairdressers are still in training.

Tyler Gesquiere, a physiological sciences sophomore, once had a scary experience at work involving a drunken man and a firearm.

Gesquiere used to work at Sports Park on the north side of Tucson.

"I guess there was a confrontation between two guys playing softball and one guy went to his truck, got a shotgun, came back into the park and started shooting people," said Gesquiere. "He hit a pregnant woman. He hit a couple of people. This happened about four, five or six years ago.'

'It was my first job. After that happened, I was like, 'I don't know if I want to work here anymore.'"

The moral of the story: There is no escaping fear unless you decide to live inside your house and sleep, perchance to dream, your life away in bed.

But even then, there's always Freddy Krueger.