Animals almost always leave a 'trail", a path that they almost always take to a specific destination (water, food, etc). it can be subtle, and sometimes takes an experienced tracker to find them.
but once found, you just set up an automatic camera to monitor the path.
Now, for STILL cameras, there are plenty of options. you can find automatic still cameras in Survival magazines or Hunting magazines, and at many gun shops or hunting shops.
Automated MOTION cameras are harder to find. They usually require some kind of short range (1 - 2 mile) radio link to a computer that then records the transmitted motion pictures digitally to the hard disk.
Once they get the picture they ant, they go in and gather up the equipment.
I saw one documentary where the cameraman mad a small "blind" (a place to hide) for his camera using MIRRORS to reflect the surrounding trees and grasses, thus hiding the camera from the animal.
Also- they use cameras with night vision capability. Sometimes they may wait in a hidden area to see if the animal will walk by (once they know it's habits.)
They set cameras up in places they know where the animals are going to be and then leave them there over night. Then they go back and collect their hardware.
Like on those nature shows like how do they get footage of animals that only come out at night.
