Over the last thirty years, the improvement in miniaturization of electrical equipment has shrunk the transmitters. Batteries are smaller and now last for weeks and months instead of just a few days. Even now, with all the improvements in the radios and batteries, the biologist is still frustrated by equipment failures. An animal might appear to have settled, so the researcher sets off to investigate. Most researchers have spent many frustrating hours tracking down an animal through thick brush only to discover the radio transmitter lying on the ground.
Animals have the amazing ability to get the most secure radio collar off of their necks.
Another problem that occurs is that the animal might move before the biologist can take a second fix. To over come this problem, tracking is often done by two researchers working together. Electrical signals don't always come from where they seem to be coming from because radio signals bounce off of objects. Trees, wire fences, cliff faces, and electrical pylons are just a few of the objects that might cause the signal to appear to be coming from the wrong spot. The researchers often assume that they know where they are while tracking the animal.