The animals do not simply role over and let you place collars on them. The methods for immobilizing animals usually include a dart gun and a tranquilizer. However, bears can run in excess of 30 miles an hour so sometimes you have to dart them from the air. This adds a definite cost to the project and inherently increases the danger or risk factor for the people involved. Once the animal is down it must be handled in a way that will not result in injury and all attempts are made to reduce the animals stress.
Critical data is recorded as the animal is processed and the collar put in place.
Animals may have to be caught annually to replace batteries or power systems that run the collars. Collars must also be tested to see if they are being detected by the satellites and that data transmission is working. Satellite systems that now play a major role in this technology are a very recent addition. This allowed scientists to track animals on a daily basis and get real time data on a variety of other scientific data. The first collar units were big and bulky.