Escaped tiger drill at Chengdu Zoo in China

Yesterday our news feeds were filled with updates about Rusty, a red panda who had escaped from the National Zoo. He was found in a bush in a nearby neighborhood and returned to the zoo, but it was a reminder that animals sometimes can outwit even a well-designed exhibit. Zoos prepare and practice for these uncommon events, as Vetstreet's Linda Lombardi knows firsthand.

One thing I learned about working at a zoo is that you need to be prepared for the unexpected. Take the time I walked out of my building into the path of an escaped lion.

Fortunately for me, the "lion" was actually a person in an orange vest with a sign that said "LION" on the back — because this happened when the zoo was doing an escaped animal practice drill.

You might imagine capturing an escaped zoo animal as involving a lot of running around and shooting tranquilizer guns. Dart guns are sometimes part of it, but not nearly as often as you might expect. And minimizing running is a big part of the strategy.

Safely recapturing a loose animal requires knowledge about animal behavior, starting with the fact that for most zoo animals, being outside their exhibits is not exactly good news. They're in an unfamiliar place that doesn't feel safe, and they probably didn't really mean to go there in the first place.

Barriers to Roaming

Dave Bernier, general curator at Lincoln Park Zoo, says that in his experience, escapes are usually a side effect of some other problem, not because it's an animal's goal to run free. For example, one escape was the result of a group of gazelles fighting. "This animal jumped out because it was being pursued," he says. "It didn't want to go there, but that's where it ended up."

Once away from the conflict, the gazelle didn't keep running — it just lay down. That's when the staff needed to react quickly, with the goal of keeping the animal still and restricting its options. "A lot of times animals will seek to go back to their enclosure if given the opportunity, so we try to give them a choice where they can do that," he says.

For a large animal that isn't life-threatening, the zoo uses a variety of equipment to keep it contained and encourage it to move in the preferred direction, without getting close enough to spook it or risk human injury. One approach is to set up a perimeter around the animal using barn curtain material that's stored in large spools in various locations throughout the zoo so it's ready when needed.

"We can make a visual barrier with this material that's like 25 or 30 feet long with only a few people," Bernier says. "The animals don't know how solid they are, and they generally don't test them as long as you provide them with enough room to move and they don't feel threatened."

Since the barrier is flexible, it can be used to funnel the animal where you want it to go. Another kind of moving barrier can be made by carrying wooden boards with handles. "We have all different sizes, from small shield size to full 4-by-8 boards with handles and eye cutouts, all the way to rolling baffle boards," he says.

With all these barriers, the idea is to take as much time as needed and to not spook the animal, which requires attention to its flight distance, or how close you can get before it will bolt. But sometimes a quicker result is needed.

"We also use everyday items like CO2 fire extinguishers and air horns," Bernier says. "If you need to keep an animal away from a downed person or away from an open gate, the CO2 extinguisher is loud and very visual. It really gets their attention and can stop them in their tracks."

Linda Lombardi at zoo

While all this is going on with the animal, the behavior of people is just as important — and sometimes problematic. "I know from my own personal experience as a teenager that if there was an animal escape, I would definitely go to it, and I think a lot of people respond the same way," Bernier says. So staff members who are not immediately involved in the recapture are trained to bring visitors into a building and to get people to leave the zoo grounds.

Practice Makes Prepared

A coordinated effort like this needs to be practiced in advance because it's better to make your mistakes when the "lion" is only a curator in a vest. That's where the drills come in. While drills aren't as big a surprise as a real escape and people generally know that one is planned, they don't know the details. 

"I'll keep it to myself, what I'm going to have the escaped animal actually do, so people can't too much mentally prepare for what to expect," Bernier says. He will then be in contact with the "animal" and give it instructions depending on how he sees staff responding. "If response at one gate is slow, I might have it go toward that gate," he says. "If someone who comes to the scene seems to violate the flight distance of the animal, I might have it move."

For an animal that's too dangerous to approach on foot even with barriers, that's where tranquilizer darts come in, which they practice shooting out of zoo vehicles. Surprisingly, though, it can be the smallest animals that are the most difficult. Bernier says they don't usually do drills for those, though they sometimes get practice when people dump an animal like a chicken or rabbit on zoo grounds.

"It's extremely challenging to get little animals," he says. "Animals are very quick to recognize what's going on when they're being pursued and there's nets around. You coordinate as a team, you have yourself in the right position, but you just happen to have your net down when the animal turns right and runs into your net. People look at you like you're an expert, but the person who nets it says, 'I got lucky.'"

After each drill there's a meeting to discuss what went right — and what didn't. In my case, I survived my encounter with the orange-vested curator and let my bosses know about the miscommunication that resulted in my walking out of the building before the "lion" was recaptured.

"That's really the value of doing the drills," Bernier says. "It's a learning process."

Read more Vetstreet pieces featuring zoos and animal parks:

What Zoos Do to Prepare for Natural Disasters

A Behind-the-Scenes Look at Treating Animals at Busch Gardens

How Zoos and Aquariums Help Endangered Species