Abstract

The Florida panther (Puma concolor coryi) is one of the most endangered mammals in the world. The free-ranging population is estimated to be between 30–50 adult animals. Historically, this species of mountain lion ranged from eastern Texas or western Louisiana and the lower Mississippi River Valley east through the southeastern United States, including Arkansas, Louisiana, Mississippi, Alabama, Georgia, Florida and parts of Tennessee and South Carolina. Up until 1966, they were hunted to protect livestock and for sport. South Florida landscape has undergone significant changes including habitat loss from human development, changes in land use to housing and citrus groves, fragmentation by roads, and introduction of exotic plants and animals. The Florida Game & Fresh Water Fish Commission began studying the panther in 1972 and it was listed by the United States Fish & Wildlife Service as an endangered species in 1981. Panthers are now only known to inhabit south Florida and a subset of the population has been studied using radio telemetry since 1981.

Between 1981 and 1998, 72 panthers have been anesthetized multiple times (1–10 times per cat) for a total of 183 capture events. Panthers have ranged from 6-mo- to 16-yr-old. Direct or indirect capture related mortality has only occurred in 3 (0.016 %) of the 183 captures. These mortalities included: a cat that died less than 8 min after being darted and was most likely a result of either a negative anesthetic reaction or a dose miscalculation; a cat died of a cellulitis and toxemia which resulted from a dart that penetrated the abdomen; and a cat that died approximately 3 days post handling but was to autolytic to evaluate further.

The field capture event involved a core capture team composed of a houndsman, veterinarian, and two biologists. The first phase involved the hound man who, with two to six hounds, located the felid scent and pursued the panther until it “treed.” Actual chases were relatively short and usually ranged from 5–10 min. The second phase involved rapidly assessing the cat’s physical condition, determining the appropriate anesthetic drugs and dose, and the preparation of a 3-cc dart with 1.5x30 mm uncollared needle. A CO₂ powered rifle with scope (Teleinject, Saugus, California, USA) was used to deliver most darts. The third phase usually involved catching the anaesthetized panther in a net as it fell from the tree. If the fall distance was greater than about 5 m, a portable wildlife cushion was used.¹ Occasionally an anaesthetized cat would remain in the tree and a biologist had to climb up and lower the cat to the ground with a rope. The fourth phase involved biomedical monitoring and research and involved: physical examination and collection of blood, hair, feces, urine, and external parasites; full thickness skin punch biopsies were taken. Panthers were vaccinated for rabies, panleukopenia, calicivirus and rhinopneumonitis. Anthelmintics were usually administered. Panthers may also have received long-acting penicillin, vitamins, and iron. Intravenous and/or subcutaneous saline was usually administered. Panthers were then fitted with radio collars (Telonics, Inc., Mesa, Arizona, USA). These collars are equipped with both an activity switch and a mortality sensor. The cats were usually monitored 3 days/wk through aerial telemetry. For additional permanent identification the cat’s ears were tattooed and a subcutaneous transponder chip was implanted. Body measurements were taken and the animal was weighed. Special studies such as semen evaluation by electro ejaculation may periodically have been conducted. Handling time to complete these tasks has ranged from 12 min to 3 hr.

Since 1981, anesthesia on the panthers has been conducted by one biologist and eight veterinarians. Not all records have complete information and the brand of the specific drug may not have been listed. Anesthetic drugs used on free-ranging Florida panthers have included acepromazine (10 mg/ml), ketamine (100 mg/ml or 200 mg/ml) (Ketaset, Fort Dodge Laboratories Inc., Fort Doge, Iowa, USA), tiletamine hydrochloride/zolazepam hydrochloride (100 mg/ml) (Telazol, Fort Dodge Laboratories Inc., Fort Doge, Iowa, USA), diazepam (5 mg/ml), midazolam (5 mg/ml) (Versed, Roche Laboratories, Mutley, New Jersey, USA), and xylazine hydrochloride (100 mg/ml). Drugs were reconstituted with sterile water as necessary.

Ketamine & Acepromazine

Ketamine (5.5–11.3 mg/kg) and acepromazine (0.01–0.1 mg/kg ) were used on the first eight panther captures. Usage of this combination was discontinued when a panther died approximately 6–8 min post dart injection. Necropsy of this animal did not reveal any significant lesions that would have otherwise explained this mortality, and thus it was assumed to be from either a dose miscalculation or an unusual reaction.

Ketamine

Ketamine at was administered for initial dart in 48 panthers. Doses ranged from 6.1–12.9 mg/kg. The initial dose and/or only one supplemental dose provided satisfactory results in 15 (31%) panthers. However, the initial dose and multiple supplements (two to nine) were necessary in 33 (69%) panthers to collect biomedical samples. Seizures were occasionally observed to occur. Biologists frequently reported the panthers had prolonged recovery and were still at or within 200 yards of the capture site for 1–7 days post capture. Three juvenile panthers were orphaned or temporarily orphaned due to their prolonged recovery for the anesthesia causing their inability to keep up with their mothers.

Ketamine & Midazolam

Combinations of ketamine (9.5–14 mg/kg) and midazolam (0.02–0.06 mg/kg) were administered to five panthers. All cats required multiple supplements (two to four).

Ketamine & Diazepam

Combinations of ketamine (7.3–12.6 mg/kg) and diazepam (0.05–0.25 mg/kg) were used on four captures. No supplements were needed. However, according to the biologist, extremely prolonged recovery times occurred.

Ketamine & Xylazine Hydrochloride

Combination of ketamine (6.4 mg/kg) and xylazine hydrochloride (0.71 mg/kg) was used on one panther. Multiple supplements (3) were needed.

Tiletamine Hydrochloride/Zolazepam Hydrochloride

Tiletamine hydrochloride/zolazepam hydrochloride (4.8–7.8 mg/kg) alone was used on 14 panthers. This was predominantly administered to male panthers to undergo electro ejaculation. The initial dose and or only one supplemental dose provided satisfactory results in 10 (71%) of these panthers. The initial dose and multiple supplements (two to five) were necessary in four (29%) panthers to collect biomedical samples.

Ketamine & Tiletamine Hydrochloride/Zolazepam Hydrochloride

Ketamine (15.5–4.0 mg/kg) and tiletamine hydrochloride/zolazepam hydrochloride (2.5–0.6 mg/kg) were used in combination for 86 panther captures. Induction time was usually within 4–8 min. Anesthetic times ranged from 12 min to several hours. The cats are usually sternal and trying to get on their feet at 45 min to 1 hr. Records note that 63 (73%) of these panthers were adequately anaesthetized with the initial dose or the initial dose and one supplemental dose. The initial dose and multiple supplements (two to six) were necessary in 23 (27%) of these panthers. However, most of these repeated supplements were needed before experience allowed appropriate dose adjustments.

The combination of ketamine (7.0 mg/kg ) and tiletamine hydrochloride/zolazepam hydrochloride (0.9 mg/kg) has been used successfully on more than 40 captures and is currently being used. If the cat is high up in a tree, the dose of tiletamine hydrochloride/zolazepam hydrochloride is slightly decreased. This has resulted in less of a fall to some cats as they are able to hang by their front feet and lowering themselves 5–6 feet closer to the net. This provides approximately 45 min of handling time. In addition, to routine biomedical procedures this dosage is adequate for minor surgical procedures such as suturing wound. No juveniles have been orphaned with this combination and the resulting shorter anesthesia time. Biologists report that the cats have usually move 0.5 mile or more by the next telemetry flight.

Acknowledgments

We acknowledge additional telemetry work, capture efforts, and data collection of D.S. Maehr, J.W. McCown, J.C. Roof, S. Bass, D. Jansen, M. Dunbar, and R.C. Belden. We also thank houndsman and marksman R. McBride for his expertise. D. Boon assisted with the database. Funding for this study was provided through the Florida Panther Research and Management Trust Fund, Florida Nongame Wildlife Trust Fund, and the Federal Endangered Species Project E-1.

Literature Cited

1.  McCown JW, DS Maehr, J Roboski. 1990. A portable cushion as a wildlife capture aid. Wildlife Society Bulletin. 18: 34–36.