Gorillas
More than 150 wildlife rangers have died on the job in the last 20 years.
A scientist called the recent viral video of Koko "highly misleading."
"What does it mean?"
WHAT'S HAPPENING
Just wait until they start playing Angry Birds.
"It was a really fun interaction."
Scientists studying Koko the gorilla witnessed a range of remarkable vocal behaviors.
Photographer agrees: "He really does look a bit cheesed off."