nowhere is this more clear than at nairobi national park. just miles away from giraffe manor, at 44 square miles, twice yet its parameters are constantly being whittled down. >> that's downtown nairobi. >> reporter: we head into the park with arthur muneza of the giraffe conservation foundation. the rwandan-born researcher is getting his ph.d. at michigan state. >> traffic jam. >> reporter: amidst the monkeys, zebras, hippos and giraffes dotting the landscape, another ubiquitous sight. so this image basically sums it up, doesn't it. that man is encroaching on his habitat. >> yes. if you look up ahead you can see the real problem. those are housing developments coming up. and a few years back you never used to have this, all this was open. animals could migrate that way. now it's inaccessible. >> reporter: that giraffe is completely holding its ground. it's like, uh-uh, i ain't moving. you're in my hood, chump. a giraffe's kick can break a lion's back, but giraffes are being killed off by a far more lethal predator, from trophy hunters to poac