Dr. Brady Barr, host of National Geographic's Danger Encounters, is kind of crazy like Steve Irwin (the Croc Hunter) was. He doesn't wrestle crocodiles but like Irwin did, however he will resort to unusual methods to examine animals up close.

Recently Barr filmed a segment for his show that had him hiding out in a wild hippopotamus suit as he attempted to get close enough to a herd to collect some of their secretion samples. He had good reason though: these hippos are unique creatures in that they are not affected by the hot African sun and never experience infections, even from severe wounds. Barr wants to know why and claims no one has ever taken samples from one of the live animals before.

Unfortunately, finding the answers to his questions may not be part of Barr's imminent future. He was forced to abandon efforts after several days of hiding out in the suit (including one six hour session) yielded no results and Barr ended up requiring rescue after he and his contraption sunk in some mud and required rescuing.

"That's when I realised the suit was just too heavy and I had to give up my experiment," said Dr Barr."The worse was just being inside for long, long hours. The boredom and monotony were just unbearable and it reached over 100 degrees in there. I'm used to working with crocodiles. They are my comfort zone. Hippos are much more stressful but we are definitely going to work with them again."

Working with hippos is more stressful than playing with crocodiles? I wouldn't have dreamed it possible, but supposedly it may be true. David Letterman also had a response to Barr's efforts. Click on the clip below to see Dave's words for Dr. Barr.

» Telegraph