According to the professor, where did the researchers place the cameras for the experiment?

Listen to part of a lecture in an Ecology class.
Professor: The activities of humans are increasingly entering closer to the natural habitats of many wild animals. Today I want to talk about how this increased human interference affects the way animals behave around humans. Well, many wild animals live in groups, and we know that it’s common for these types of animals to live in a social hierarchy. This social hierarchy dictates how the members of the group function since every member of the group is assigned a rank.
    Okay, now let’s explore and elaborate further. The leader, the alpha, is mostly the dominant male or female that commands all of the other animals in its group. The hierarchy may change if a member is forced to leave from the pack or if the pack accepts a new member. In addition, if an alpha dies or gets replaced, the alpha position is always filled from within the pack. Also, don’t forget that there is also the second in command, the beta. The beta is submissive only to the alpha and dominates every other member of the group. Being alpha has certain privileges, like being the first one to eat food, subordinate members all have to wait their turn. And the alpha is usually the biggest or the strongest member of the group. So what happens to a group of animals living in a social hierarchy when they come into contact with humans? How does their behavior change? Does it change? Let’s now discuss an interesting experiment done out in the Arizona desert. Land development in the area is bringing the human population very close to indigenous animals. Let’s discuss one of these aboriginal species further.
    Coyotes are an animal that are being forced to come into increased contact with humans. They are animals living in a social hierarchy, so the scientists wanted to see how human presence affected their behavior. They also wanted to be as non-intrusive as possible, so they set up camera traps in the....
S1: Wait, I’m sorry, you mentioned camera traps. What is that?
P: Oh, sure, camera traps are cameras that have infrared triggers. The infrared beams are invisible, so animals can’t see them. When an animal crosses the beam, the camera takes a picture of it, so the camera traps a picture, not the animal.
S1:Oh, it’s a relief.
P: All right. So the researchers placed these camera traps all over the coyote pack’s territory and in a few areas outside its territory. Guess what happened? After leaving the cameras out in the open for some time, the researchers went back to collect the pictures they had taken. The researchers recovered a lot of pictures of the subordinate members, inside and outside of their territory. But they only got a few pictures of the alpha outside of its territory, and they got no pictures of the alpha within its territory, not even one. And this puzzled the researchers. Does anyone have any idea how this might have happened?
S2: Maybe the camera placements were too random or something? I mean, maybe the natural trails that the alpha coyotes used were too far away?
P: No, but good guess, The cameras were intentionally placed directly on the paths of known coyote trails, and, actually, specifically on the trails used by the alpha.
S1: Then, could it be the age of the animal? Maybe the older animals had more experience with humans, so they knew to be more careful than the younger animals?
P: No, and remember, being the alpha doesn’t necessarily mean that the animal is the oldest animal in the pack.
S2: Maybe the alpha was alpha because it had the keenest sense? So maybe it could smell the humans?
P: Hmm, no, but you’re getting close. You’re almost there. Think about the alpha. The alpha is the only animal in the pack that can freely roam over its territory unrestricted....
S1: Oh, I got it! The alpha saw the humans setting up the cameras!
P: Yes! The alpha had actually seen the humans setting up the cameras and was instantly wary of them. Remember, only the alpha has the burden of being required to know absolutely everything that is going on in its territory. So the alpha knew to avoid the cameras but didn’t quite see the cameras as a threat. Human interference did cause a change in its behavior, which implies that animals don’t just ignore human invasion into their territory. And we have to acknowledge this as we keep expanding our territories. The animals would have had a greater reaction had the camera traps actually caused harm to any of the subordinates.