Day after day and morning after morning, squirrels scamper across campus almost oblivious to the thousands of passersby on campus, but the question remains. Why are they so tame?

Richard Yahner, professor of wildlife conservation, attributes the fearlessness of on-campus squirrels to two factors: constant feeding and a lack of any real predator.

Wild animals tend to become acclimated to their surroundings and Penn State squirrels are not preyed upon by any other wildlife -- especially not the thousands of people that walk by them daily. Animals learn to save energy and when the squirrels are around students, it is not a worthy cause to exert energy, Yahner said.

This acclimation comes mostly from young squirrels learning from the actions of other squirrels exactly who are their predators, Yahner said.

"There is no fear because there is no predator around," he said. "There are no dogs or cats on campus. And the squirrels are in association with thousands of students everyday and the students don't tackle or chase them."

Kate Farrara (senior-marketing) had a different explanation of the campus squirrel's behavior.

"I really do believe Penn State alumni come back as squirrels. They are following us around to remind us to have a good time," she said.

Asked about the campus squirrels, director of WPSX-TV (Channel 3) Patrick Mansell said, "They have been around people all their lives and those people feed them, they know where their bread is buttered, I grew up here and they were tame then too."

Although the campus may have a surplus of these squirrels, it is to be expected in any area where there are large trees that provide food and nest sites. If there were more evergreen trees around campus, Yahner doubts the number of squirrels would be as high.

Even though the squirrel population on campus is large, the self-regulation exhibited by the adult female squirrels is the primary means of steadying the population. All squirrels know each other by scent and rarely do squirrels from areas outside campus begin living on campus, Yahner said.

While the squirrels really don't need food from students, Yahner said there's really nothing wrong with the occasional popcorn kernel or French fry. In most cases, the feeder may also benefit.

"They don't have to be fed, but in most cases, its just junk food, but it does serve as a way for people to connect to wildlife," Yahner said.

As for concerns of diseases such as rabies, the chances of a gray squirrel carrying rabies is relatively small and those feeding squirrels really don't need to be worried, he added.

One of the greatest benefits of the squirrels, said Krissy Zeiser (sophomore-sociology), may be the joy that they bring to some students.

"It's definitely something people remember about Penn State. ... It brightens the saddest of days to see these crazy squirrels," she said.

But why are there only gray squirrels? While Yahner was not completely sure, he attributed it mostly to a lack of proper habitat for other types of squirrels. More open, wooded areas are needed for fox or red squirrels. In addition, gray squirrels are the most prevalent of all squirrel species in central Pennsylvania.

Paul Ruskin, Office of Physical Plant (OPP) custodial services coordinator, explained in an e-mail message that the squirrels serve as a way to check the actions and evaluate the success of OPP.

"We see squirrels as living proof that OPP landscapers are keeping our campus healthy and green. Squirrels add a peaceful ambience and provide some of the 'parkness' of University Park," he said.

Heather Tyson (freshman-journalism) agreed with Ruskin.

"I think basically it's the whole nature thing. Penn State is already an arboretum, so it just adds to the whole nature element and makes it very homey," she said.

However, the most important job of the squirrels may be bringing nature to the students, Yahner said.

"These gray squirrels bring wildlife to people who have never experienced it. They serve an aesthetic purpose on campus by bringing the urban wildlife to the students.