The big cats' roar is growing louder.

And zoo director Terry Lincoln was hearing them Friday as he gave a pair of visitors a guided tour of the work-in-progress exhibit that will house snow leopards and tigers and open this summer. The $1.2 million exhibit is the centerpiece of Dakota Zoo's "Make the Big Cats Roar" campaign that was responsible for bringing big cats to Bismarck.

Two public viewing areas are taking shape, as is a separate den area.

One snow leopard, Jerry, is at the zoo, but in seclusion. A second snow leopard is waiting in a Des Moines, Iowa, facility and probably will be here in mid-May.

Three 7-month-old tiger cubs are being housed at a big-cat facility in Myrtle Beach, S.C. Lincoln expects them to arrive at the zoo closer to summer. May also is when the side-by-side but separate enclosures should be finished.

If all goes as planned, the exhibit should open the first week of July, Lincoln said.

Work started last July and continued through most of the winter, including Friday.

The 300- by 400-foot tiger enclosure will feature one viewing area that will overlook the grounds, which will feature a waterfall and a pond.

A 16½-foot fence with a solid overhang will separate people and tigers.

"There's no way a tiger can climb out," Lincoln said.

The adjacent leopard enclosure will be covered, Lincoln said, because "snow leopards are always climbing and jumping." The enclosure will be 65 feet by 130 feet.

Lincoln said he believes both exhibits will be among the largest in the country.

The cats will share a second viewing, allowing zoo-goers to split their time between watching leopards and tigers. Since the big cats will be on exhibit year-round, the viewing areas will be heated.

And like the prairie dog exhibit, both exhibits will feature pop-ups, or bubbles, from which the public can walk through a tunnel and get a look from inside the enclosure.

To prevent the tigers and leopards from interacting, a solid barrier will separate them.

The separate den area will feature a rock face and give each cat a private area out of the limelight. Zoo keepers have access to them, but it won't be open to the public.

Only the senior keepers will work with the big cats, and they will have a two-week run through of procedures.

"It's all about safety," Lincoln said.

(Reach outdoor writer Richard Hinton at 250-8256 or richard.hinton@;bismarcktribune.com.)