One of the biggest difficulties researchers and rehabilitators face when studying an animal in its natural habitat is making sure that the animals sufficiently fear humans. Or, for the bigger critters, that they don't chomp down on a scientist's leg.

So, how do well-meaning scientists and wildlife caretakers get around these sticky issues? They play dress-up — all in the name of science, of course.

By looking and even smelling like an animal — and more importantly, not like a human — these folks are giving animals a chance at a normal life.

Scientists in panda suits

Scientists at China's Wolong Panda reserve in Sichuan Province outfitted themselves with panda suits in an effort to successfully introduce captive-bred cubs into the wild.

Instead of humans raising the pandas in captivity, the panda mothers are raising their cubs in a protected woodland. The hope is that these pandas will develop the skills they need to survive. Scientists monitor the animals on CCTV, always ready to don their panda suits if any show signs of distress or need medical attention.

And while we can’t be sure the panda cubs are fooled by the costumes, we can assume that they wouldn’t know what a real human looked like if they saw one.

Undercover whooping crane parents

For the past 14 years scientists have showed to what lengths they will go to bring a species back from the brink of extinction. With just 550 cranes left in the world (a much better number than the 22 total that existed back in 1940), every crane’s life matters. Many of the birds live in the wild, but about 95 are being bred in captivity by human parents.

These humans don’t just waltz in for feeding time. Instead they wear poncho-like costumes so the babies don’t mistake their human caretakers for parents. The scientists use a whooping crane puppet as a parent to teach the babies skills they will need to survive. The scientists are so dedicated to the task they train the birds to migrate south to Florida using a lightweight plane.

It hasn’t been a flawless plan. "We have great success in doing this in that the birds survive,” said Glenn Olsen, a veterinarian who spends her time in one of those ponchos to care for the birds. “But they seem to be having trouble nesting and raising chicks, and we don't know how much of the component of raising chicks is innate or learned.”

Rehabilitator dresses as bobcat

Since 1994, the devoted folks at the Wildlife Education and Rehabilitation Center in Morgan Hill, California, have been going the extra mile...and then some. To care for bobcat kittens and get them ready for the wild, rehabilitators dress up as great big bobcats, walk on all fours and don’t speak. To really sell the story, according to TreeHugger, the humans then get rubbed down with herbs and dabbed with bobcat urine, all to satisfy the super strong olfactory sense of each kitten.

'Star Wars' costume designer made a moose suit for science

Husband and wife team Joel Berger and Carol Cunningham wanted to find out if the decline of species like wolves and grizzly bears in the lower 48 states would affect how moose react to evidence of natural predators. They tried a variety of ways to get wolf urine and bear dung close to the moose, but just couldn’t get close enough to gauge a reaction, even with the help of slingshots.

The next logical step? Ask a designer who worked on one of the "Star Wars" films to design a moose suit that could fool a moose. Berger took the front and Cunningham took the back, allowing the moose-shaped pair to walk right up to their subjects, and even to come nose to nose with one.

They found that moose in the lower 48 didn’t have much of a reaction to wolf urine or bear dung, but that moose up in Alaska, where those predators are still common, immediately reacted. With the wolf urine, the northern moose would be on high alert, looking around for minutes at a time. With the bear dung, Berger said the moose "freaked out, basically."

A rover dressed as a penguin

It's doubtful that a 150-pound scientist in a penguin suit could convince a group of 30-pound penguins that he’s one of the gang. So, instead of dressing up a person, a group of scientists studying king penguins in Adelie Land, Antarctica dressed up a rover as a baby penguin.

The fluffy faux baby drove around on four wheels collecting readings from heart rate monitors that were attached to 24 penguins. As this species of penguin is quick to startle, the rover was a perfect way to get within two feet of each penguin, the distance required to obtain a reading.

The heart rate measurements enabled the researchers to determine which kinds of human interference caused the most stress. They found that humans were the biggest stresser. Robots that weren’t dressed as baby penguins were a little less suspicious. The fluffy penguin robot? A big win, not provoking a stress response from the group.

"Chicks and adults were even heard vocalizing at the camouflaged rover, and it was able to infiltrate a crèche without disturbance,” said one of the researchers.

A boat disguised as a crocodile

How much poop do 4,000 hippopotamuses create? Enough to kill.

Scientists saw that fish were occasionally dying in large numbers in Kenya’s Mara River and thought it might be caused by the hippos using the river as their personal toilet. In order to get sample readings, the scientists had to get close to the hippos, not exactly a safe thing to do.

Instead, they outfitted a 2-foot-long, 13-pound boat with a foam crocodile head and green fabric so that it could swim near the 3,000-pound behemoths. And it worked. Mostly, the boats were ignored and scientists collected their samples leading them to discover that the poop was indeed responsible for the mass deaths of fish.

One hippo, however, was not impressed by the boat and actually gave chase. See the excitement in the video below.

Related on MNN:

6 scientists who play dress-up for animals
By looking and even smelling like an animal, these folks are giving animals a chance at a normal life.