Collaring Wildlife

October 19, 2023

Question: How do wildlife collars work and what factors are taken into consideration before the California Department of Fish and Wildlife (CDFW) attaches them?

Answer: CDFW attaches collars to animals to study their behaviors, movements and habitat use as a population or as an individual. Collars can also be used to track and manage animals that have the potential of becoming involved in conflict with humans.

Age, health and the weight of the animal are major factors in the decision to attach collars. Collars can appear bulky, but CDFW ensures it does not put anything on an animal that is more than five percent of its body weight. More often collars are between one and three percent of the animal’s weight. Collars are specifically designed for the species, age, weight and purpose of the data collection needs. Generally, younger animals are equipped with lighter collars that are worn for a shorter duration. Adult animals may wear collars for up to two years. Most collars are programmed to drop off after they’ve gathered and sent enough data and prior to battery failure. If an animal begins to outgrow the collar it’s wearing, CDFW can trigger a drop-off mechanism that frees the animal from the device. Cotton spacers integrated into the belting are commonly used as a failsafe in the event of collar failure.

CDFW currently has hundreds of collars on a wide variety of wildlife including desert bighorn sheep, bears, deer, elk, mountain lions, bobcats, gray wolves, Sierra Nevada red fox and others. CDFW partners with the Fresno Chaffee Zoo in a project that even has collars on blunt-nosed leopard lizards.

Wildlife collars communicate with CDFW scientists in two ways. Some use VHF radio signals, which require researchers to be relatively close to detect the signal. More advanced collars that use GPS can send data via satellite to computers hundreds of miles away. Those collars also receive signals if CDFW would like to alter settings or have the collar drop off the animal. When collars fall off or are removed in the wild, CDFW retrieves those devices for later use.