Discussing methods and drugs in tranquilizing a lion or other big cat with a dart

I was prompted to write about this topic after reading a new story, today, about a lion, Kimba, which escaped from a circus near Ladispoli, north-west of Rome, Italy. The lion prowled the small town’s streets resulting in a curfew for the residents. The police were called and they contacted an expert, Bisegna, on tranquilizing large animals using tranquilizer darts fired from a rifle.

Kimba an escaped lion who was tranquilised with a dart gun
Kimba an escaped lion who was tranquilised with a dart gun. Images in the public domain (deemed).
Two useful tags. Click either to see the articles:- Toxic to cats | Dangers to cats

The intention was to subdue the animal and allow the authorities to transport him back to the circus where, incidentally, there were protesters demanding that the enslaved animals be released. I, for one, am wholeheartedly for the protesters and against circuses and even zoos for that matter but that is another discussion.

Bisegna travelled to the location of the lion where he discovered that another marksman had tried to tranquilize the lion but the dart hit the foot and made him jumpier. Kimba became more excitable which is not an untypical reaction to being darted with a tranquilizer which doesn’t work properly.

A police helicopter with an infrared camera located the lion. Bisegna spotted Kimba in the vegetation using an infrared scope on his rifle and was about 35 m away which was a little too far when using a tranquilizer dart from a rifle. However, there was a slight wind behind Bisegna and he aimed high to compensate for the dipping trajectory. He succeeded in hitting Kimba who walked for about 800 m before he fell asleep.

The dart had a GPS tracking chip inside it so the authorities were able to find him and return him to the circus.

The anaesthetic lasted for about 40 minutes, ample time for the task.

The information above tells us that about 35 meters is the limit to dart a large animal with a rifle.


Firing a tranquilizing dart at large cats with a rifle is problematic. I can recall in the past a puma (mountain lion) being tranquilized because they had wandered into a village and the rangers inadvertently killed the cat because there was too much tranquilizing drug in the dart. The quantity is critical.

In another incident, one that you might recall, a private zoo owner in America, Thompson, released all of his animals in an act of rage and defiance against the authorities. This allowed several large big cats to roam loose and a veterinarian was called to tranquilize them. She fired a dart at a 300-pound tiger. She said, “The dart’s anaesthetic did nothing to subdue the big cat”. The cat just went crazy and “sort of exploded”. The tiger was shot dead as were the other animals; all of them as I recall.

What kind of drugs are used to tranquilize animals using darts?

A range of drugs are used on my research. Online, there is a very useful study about tranquilizing jaguars in the wild. The jaguar is of a very similar size to lions and tigers albeit a little bit smaller. The author of the study provides a table reviewing anaesthesia dosages from previous literature for the “chemical immobilisation of free-ranging jaguars”. I have reproduced it below.

Another study tells me that lions in the wild in north-eastern and north-western Rhodesia as it was then called (now Zimbabwe) were tranquilized using darts containing the drugs Sernylan, Rompun and Acetylpromazine. The study is dated 1977 so these drugs may have been superseded by more modern drugs or their names changed.

RELATED: Puma captured and tranquilized in California backyards (video). No shooting. Great.

Targeted area of the body

The targeted area on the body of the animal should be carefully considered and my research indicates the preference should be for the rump area (upper rear limb). But even there are some dangers because the dart might impact the femoral bone and/or the sciatic nerve. The length of the dart is going to be important to avoid this kind of damage.

Shooting the dart into a forelimb risks missing and hitting the neck or head of the animal where serious harm can be inflicted.


The conclusion that I bring to this page about tranquilizing big cats with darts shot from rifles is that it is problematic or to put it another way, it’s dangerous both for the rifle man or woman and the big cat or other big animal as they are dangerous animals. They are top predators. A dart shot into them can excite them and make them more aggressive. Or the animal can be killed.

RELATED: Side effects of cat tranquilizers

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