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Radio collars on lions

If you go to the Serengeti, Tarangire or Matambwe, you might see a radio-collared lion. Collars are essential for monitoring each of these populations (no collars are necessary in Ngorongoro Crater where the lions are easily located by eye). Here are some of the more common questions about radio-collars.

What is a radio collar?

A radio collar is a wide band of machine-belting fitted with a small radio transmitter and battery. The transmitter emits a signal at a specific frequency that can be tracked from up to 5 kms away. When trying to locate a particular collared lion, the researcher dials the appropriate frequency and drives while listening for the signal (“beep-beep-beep”). A directional antenna is mounted on top of the vehicle, and once the signal is detected, the researcher simply drives in the direction where the signal is loudest.

Why use radio collars?

In most habitats, lions can be difficult to find. Pride territories may be as large as 400 km2, and lions are often hidden in dense vegetation or rough terrain. In order to see each lion every 2–3 days, we therefore rely on radio telemetry. Radio-collars permitted rapid detection of a major disease outbreak in the Serengeti in 1994 and enabled an eventual diagnosis for the cause of the die-off. Subsequently, a large-scale vaccination program for village dogs was established to protect Serengeti wildlife from canine distemper. Similarly, radio tracking revealed the extent to which the Tarangire lion population is affected by retaliatory killing by Maasai pastoralists outside the national park, thereby leading to the large-scale conflict-mitigation program currently underway.

How do we radio-collar lions?

A Serengeti veterinarian uses a dart gun to inject the lion with a drug called Telazol. Once the lion is immobilized, we fit the radio collar and also collect a set of biological samples (blood, urine, saliva, ticks) to measure physiological status. The lion is typically back on its feet after two hours, and the vet remains with the lion until it is fully recovered.

Do collars bother lions?

The lion takes a day or two to get accustomed to the collar, but she soon ignores it (as do domestic dogs). The collar is snug enough to prevent getting stuck in vegetation and loose enough to be comfortable whether the lion is upright, stretched out on its side or curled up in the rain.

Do collars have any negative long-term effects on lions?

Over the past 36 years, we have found no difference in life span or reproduction between collared and un-collared lions. Nevertheless, we have set the strength of the transmitters so that the batteries last for over four years, thus minimizing the number of times that the collar will need to be replaced on each animal.