When sneaking up on a silverback gorilla, you want to be quiet and careful.
That's a lesson I learned here in the jungle of the Central African Republic from Angelique Todd, who spends nearly every day of her life with a family of gorillas.
On one particular morning, we were just a few feet from a roughly 500-pound, six-foot-long wild animal, who was alternately daydreaming and nodding off.
"He's sleeping," said Todd. "[The silverback] is the dominant male. So the male gorillas develop this huge size. They're almost double the size of the females."
The silverback in question, named Mikumba, is the head of a family of 11 gorillas.
"So this is one of the infants that we haven't seen yet," said Todd, pointing to a baby gorilla. "He's 2-and-a-half. He spends nearly all his time with his dad."
Todd is something of a modern day Dian Fossey, the American scientist who studied gorillas in Africa and was the inspiration for the movie "Gorillas in the Mist."
But the family of gorillas Todd follows aren't mountain gorillas, the type Fossey studied. They're western lowland gorillas, an animal very few people have ever gotten very close to. Adult males are called silverbacks because their hair turns grey with age.
"For years, all I ever saw was them running away," said Todd. "I didn't see anything at all. Three years. So, whenever I come see them, I'm just so grateful to them for accepting us."
Over many years, Todd -- a researcher with the World Wildlife Fund -- and a team of local Pygmie guides in the Central African Republic have "habituated" the gorillas to human contact.
There is no other place on Earth where you can see the silverback gorilla up close in the wild. It was a difficult, dangerous job, which Todd says involved daily rejection by the gorillas.
"Yes, every day being screamed at," she recalled. "Or being charged and just having to take it and then just moving on. It can be really scary... they can kill you, basically. If you make one charge, for example, if you look too frightened, you never know if he's actually gonna grab you, but you just have to stand there, even though you're really, really scared."
When Mikumba finally roused himself, it became clear why it would be so terrifying to be charged by a silverback gorilla.
Gorillas in All Their Glory
"Nightline" spent a day following as the family of gorillas made its way through the jungle, eating as they went.
"So, silverbacks do a lot of stopping and listening so the females go out ahead... and he stays waiting behind, just listening," explained Todd.
While the family moved forward, the silverback loomed in the back, watching over everyone and listening intently for any signs of danger.
Todd and the Pygmies were constantly cooing and clucking, sounds they've used for years to let the gorillas know they're there and harmless.
While filming, something happened that surprised even Todd. Normally the gorillas can only be seen in heavily wooded areas, but suddenly they entered a clearing, where they could be seen in all their glory.
"Oh, Mubenge!" Todd explained excitedly, recognizing one of the gorillas. Even after nine years of following this family, she says it's thrilling each time the gorilla emerges, especially when the silverback Mikumba arrives.
"Here he comes!" she exclaimed. With a rare clear view, there really was a sense of what a majestic beast he is, with a chest that looks armor-plated and forearms that seem the size of car doors.
Even while enjoying a lazy lunch, Mubenge looked like King Kong.
"I worked with captive gorillas for a long time but I would never imagine that I'd be walking around and that we'd have successfully habituated a group of gorillas just to the point that they have no problem with us," said Todd. "I think it's hard for you to imagine how aggressive they can be. If that male wants to go for us now, he's got huge teeth and he's extremely strong and he could just kill you."
Todd knows that firsthand, as she has had to pay a price for her dedication to animals.
"I was attacked by a chimpanzee, eaten by a chimpanzee, 15 years ago in a zoo," she recalled. "There was a hole in the cage, the chimpanzee managed to ... grab my arm out and bring it into [the] cage and bit my thumb and finger off, nearly half of my arm. I'm actually really lucky I kept my arm. And the annoying thing was even though he ate my finger and my thumb he kind of spat them out. I brought them to the hospital and they couldn't put them back on."
Gorilla Population Threatened by Elephants, Man
Her personal life has also suffered from spending the better part of 10 years in the forest.
"You don't [have a personal life]," she said. "You make huge sacrifices in your life to be in the forest with the gorillas. Once you go down that direction it's tough to turn back and you just hope that someone will turn up. Who knows what will happen. Well, certainly while Mikumba's around, I'll still be here."
While Todd feels safe with the gorillas, she does always have to be on guard for elephants -- possibly the craftiest, most aggressive animal of the jungle. Adult elephants, ever protective of their babies, have attacked Todd and the gorillas before.
An even bigger danger to the gorillas, however, is man.
"If they get the chance, yes, they will eat the gorillas," Todd said of the locals. "And apparently, it's very tasty meat, but I couldn't possibly try it. For people's attitudes here, they're just animals. They don't see that they're sentient beings. They're just meat."
One of the benefits of habituating gorillas is that local people get to spend more time with them and see how near-human they are. Todd's program employs 60 people in the impoverished nation.
However, habituation is controversial because it can make gorillas too trusting and, therefore, more vulnerable to poachers. Bringing tourists in, as Todd sometimes does, can also expose the animals to human diseases.
"I think it's worth the risk," she said. "I really do."
Worth the risk because it gives researchers a chance to study a species that many fear will no longer be with us in 50 years, a species to which Angelique Todd has dedicated her life.