Robert Lobato, 49, of Valencia, trekked up one of Towsley Canyon's hiking trails as the Monday afternoon heat began to let up.

The seasoned hiker loves the canyon for its lush foliage and trees - not to mention the wildlife that he says most other Santa Claritans rarely take the time to see.

"They're really missing part of nature that's in their back yard," Lobato said at the beginning of his 5.1-mile hike. "Further up, pockets of oil are bubbling up from the earth."

He was talking about the black goo that seeps up from cracks in the ground and shimmers on the surface of some of the canyon's creeks.

Parts of the western Santa Clarita Valley had been rich in oil before drillers depleted it by the early 1900s.

Today, Towsley Canyon is part of the 3,050-acre Santa Clarita Woodland Park, which includes East, Rice, Pico and Towsley canyons and Mentryville.

Black bears, coyotes, mountain lions, bobcats, foxes, badgers and deer live in the sprawling wilderness area, said Rorie Skei, a spokeswoman for the Santa Monica Mountains Conservancy, which operates the parks.

In the springtime, dozens of species of colorful flowers bloom. Hikers can view fault lines and sandstone formations along the trails.

"It's such a nice respite," Skei said. "It's just minutes from the populous San Fernando Valley, but it is a slice of true wilderness."

Ed Davis Park in Towsley Canyon has few amenities aside from its grassy lawn and picnic area. People who hike one of the nearby trails said that's one of the things they like about it.

The trails also serve for some as a scenic place to exercise for free.

"I go to a gym, too, but it's so much more interesting here," said Tom Murphy, 68, of Newhall, just as he returned from a nearly two-mile trek.

Murphy has seen coyotes, snakes, lizards and other wildlife in a decade of walking along the rugged Towsley Canyon trails at least a couple of times a week.

And he credits the hikes with helping him drop more than 30 pounds.

"A treadmill gets boring," he said. "I never get bored here."