Vitamin A concentrations in serum and liver from Florida panthers

Many of the anomalies and clinical signs afflicting the Florida panther (Felis concolor coryi) are suggestive of vitamin A deficiency. Our objectives in this study were to determine if a vitamin A deficiency exists in the free-ranging panther population and to determine if there are differences in vitamin A levels among various subgroups of free-ranging panthers. Retinol concentrations were used as an index to Vitamin A concentrations and were determined in serum and liver from free-ranging (serum, n = 45; liver, n = 22) and captive (serum, n = 9; liver, n = 2) juvenile and adult Florida panthers from southern peninsular Florida (USA), and in liver from free-ranging cougars (F. concolor subspp.) from Washington (USA) and Texas (USA) between November 1984 and March 1994. Combined juvenile (6- to 24-mo-old) and adult (> 24-mo-old) free-ranging Florida panthers had mean +/- SD serum retinol concentrations of 772.5 +/- 229 pmol/ml. Adult free-ranging Florida panthers had mean liver retinol concentrations of 4794.5 +/- 3747 nmol/g. Free-ranging nursing Florida panther kittens (age < 1 mo) had mean serum retinol concentrations of 397.9 +/- 69 pmol/ml. Among subgroups of free-ranging Florida panthers, females had higher corrected mean serum retinol concentrations than males and adult free-ranging Florida panthers had higher mean liver retinol concentrations than juveniles. Retinol concentrations in free-ranging Florida panthers did not differ significantly from those in captive panthers (liver and serum) or other free-ranging cougars (liver). Based on limited published values and our controls, a vitamin A deficiency could not be demonstrated in the Florida panther population nor were any subgroups or individuals considered deficient.     

Causes of mortality of free-ranging Florida panthers

The Florida panther (Puma concolor coryi) is one of the most endangered mammals, with the entire population estimated to consist of only 30-50 adult animals. Between 1978 and 1999, 73 free-ranging Florida panther carcasses were submitted for postmortem evaluation, of which 47 (64%) were radiocollared and 26 (36%) were uncollared cats. Overall, mortality of panthers > 6-mo-old was due to vehicular trauma in 25 (35%), intraspecific aggression in 19 (26%), illegal kill in seven (10%), research activities in two (3%), infectious diseases in two (3%), esophageal tear in one (1%), pleuritis in one (1%), pyothorax in one (1%), aortic aneurysm in one (1%), atrial septal defect in one (1%), and causes of death were undetermined in 13 (18%) due to autolysis. Of the 25 panthers that were killed by vehicular trauma, 20 (80%) died between October and April. This coincides with increased number of winter visitors to south Florida. Among radiocollared panthers, intraspecific aggression was the primary cause of mortality for 19 (41%) dead cats. Of these cats, 16 (84%) were males and 14 (88%) were either less than 3 or more than 8-yr-old. These animals were probably fighting to establish or retain territory. Among the 26 uncollared panthers, vehicular trauma was the primary cause of mortality and was responsible for 16 (62%) deaths. This study documents the causes of mortality and the age, sex, and seasonal mortality trends for both radiocollared and uncollared free-ranging endangered Florida panthers over a 21-yr-period.     

Florida Panther Habitat Selection Analysis of Concurrent GPS and VHF Telemetry Data

Abstract: Florida panthers (Puma concolor coryi) are listed as an endangered subspecies in the United States and they exist in a single Florida population with <100 individuals; all known reproduction occurs south of Lake Okeechobee. Habitat loss is the biggest threat to this small population and previous studies of habitat selection have relied on very high frequency (VHF) telemetry data collected almost exclusively during diurnal periods. We investigated habitat selection of 12 panthers in the northern portion of the breeding range using 1) Global Positioning System (GPS) telemetry data collected during nocturnal and diurnal periods and 2) VHF telemetry data collected only during diurnal periods. Analysis of both types of telemetry data yielded similar results as panthers selected upland (P < 0.001) and wetland (P < 0.001) forested habitat types. Our results indicated that forests are the habitats selected by panthers and generally support the current United States Fish and Wildlife Service panther habitat ranking system. We suggest that future studies with greater numbers of panthers should investigate panther habitat selection using GPS telemetry data collected throughout the range of the Florida panther and with location attempts scheduled more evenly across the diel period. Global Positioning System radiocollars were effective at obtaining previously unavailable nocturnal telemetry data on panthers; however, we recommend that panther researchers continue to collect VHF telemetry data until acquisition rates and durability of GPS collars improve. (JOURNAL OF WILDLIFE MANAGEMENT 72(3):633–639; 2008)     

Parasitic helminths of black bear cubs (Ursus americanus) from Florida

Twenty-two Florida black bear (Ursus americanus floridanus) cubs (< or = 12 mo old) from Florida were examined for endoparasites between 1998 and 2003. Eleven species of helminths were found (8 nematodes, 2 trematodes, and 1 acanthocephalan). The most prevalent helminths were Ancylostoma caninum (64%), Macracanthorhynchus ingens (36%), Strongyloides sp. (27%), Baylisascaris transfuga (23%), and A. tubaeforme (14%). New host records include A. tubaeforme and Brachylaima virginianum. This is the first report of B. transfuga in black bears from Florida.     

A Conservation-Based Approach to Compensation for Livestock Depredation: The Florida Panther Case Study

Calf (Bos taurus) depredation by the federally endangered Florida panther (Puma concolor coryi) on ranches in southwest Florida is an important issue because ranches represent mixed landscapes that provide habitat critical to panther recovery. The objectives of this study were to (1) quantify calf depredation by panthers on two ranches in southwest Florida, and (2) develop a habitat suitability model to evaluate the quality of panther hunting habitat on ranchlands, assess whether the model could predict predation risk to calves, and discuss its potential to be incorporated into an incentive-based compensation program. We ear-tagged 409 calves with VHF transmitters on two ranches during 2011–2013 to document calf mortality. We developed a model to evaluate the quality of panther hunting habitat on private lands in southwest Florida using environmental variables obtained from the Florida Natural Areas Inventory (FNAI) Cooperative Landcover Database and nocturnal GPS locations of panthers provided by the Florida Fish and Wildlife Conservation Commission (FWC). We then tested whether the model could predict the location of calf depredation sites. Tagged calf loss to panthers varied between the two ranches (0.5%/yr to 5.3%/yr) and may have been influenced by the amount of panther hunting habitat on each ranch as the ranch that experienced higher depredation rates contained a significantly higher probability of panther presence. Depredation sites of tagged calves had a significantly greater probability of panther presence than depredation sites of untagged calves that were found by ranchers in open pastures. This suggests that there may be more calves killed in high risk environments than are being found and reported by ranchers and that panthers can hunt effectively in open environments. It also suggests that the model may provide a means for evaluating the quality of panther hunting habitat and the corresponding risk of depredation to livestock across the landscape. We suggest that our approach could be applied to prioritize and categorize private lands for participation in a Payment for Ecosystem Services program that compensates landowners for livestock loss and incentivizes conserving high quality habitat for large carnivores where livestock depredation is a concern.     

Cryptorchidism in Florida panthers: prevalence,features, and influence of genetic restoration

The overall prevalence of cryptorchidism in Florida panthers (Puma concolor coryi) from 1972-2001 was 49% (24/49), with a significant increase over time. The earliest age at which descent of both testicles was known to occur was 2 mo and the latest was 10-13 mo. Delayed testicular descent was documented in 23% (8/35) of juveniles examined. Most retained testicles were in the inguinal canal. There was no apparent difference in reproductive success between cryptorchid and normal panthers, although no bilaterally cryptorchid panthers were known to have sired litters. Cryptorchidism was thought to be a manifestation of inbreeding and was one of several factors that led to the development of a genetic restoration plan whereby eight female puma from Texas were released into the panther population in 1995. None of the progeny resulting from genetic restoration efforts has been cryptorchid. This report provides evidence that cryptorchidism in panthers is genetically rather than environmentally based, and demonstrates the utility of genetic restoration for eliminating certain deleterious traits that result from inbreeding.     

Transmammary infection of free-ranging Florida panther neonates by Alaria marcianae (Trematoda: Diplostomatidae)

Two freshly-dead female Florida panther (FP) neonates, Puma concolor couguar (=Puma concolor coryi), an 11-day-old and a 17-day-old, were collected in the Florida Panther National Wildlife Refuge (26 degrees 14'N, 81 degrees 36'W), Collier County, Florida. The 2 neonates were siblings and had presumably fed only on milk from the dam since birth. A 12-day-old female FP neonate was collected in the Big Cypress National Preserve (26 degrees 05'N, 81 degrees 15'W), Collier County, Florida and had also fed only on milk from the dam since birth. Milk was the only food item found in the gastrointestinal tract of these neonates. Mesocercariae and diplostomula of Alaria marcianae were collected from the lungs of the 3 neonates, indicating a transmammary route of infection. No mesocercariae, diplostomula, or mature A. marcianae were seen in the stomach or small intestine. The probable paratenic host for the A. marcianae infection in the adult Florida panther is the raccoon (Procyon lotor).     

Intentional genetic introgression influences survival of adults and subadults in a small, inbred felid population

1. Inbreeding and low genetic diversity can cause reductions in individual fitness and increase extinction risk in animal populations. Intentional introgression, achieved by releasing genetically diverse individuals into inbred populations, has been used as a conservation tool to improve demographic performance in endangered populations. 2. By the 1980s, Florida panthers (Puma concolor coryi) had been reduced to a small, inbred population that appeared to be on the brink of extinction. In 1995, female pumas from Texas (P. c. stanleyana) were released in occupied panther range as part of an intentional introgression programme to restore genetic variability and improve demographic performance of panthers. 3. We used 25 years (1981-2006) of continuous radiotelemetry and genetic data to estimate and model subadult and adult panther survival and cause-specific mortality to provide rigorous sex and age class-specific survival estimates and evaluate the effect of the introgression programme on these parameters. 4. Genetic ancestry influenced annual survival of subadults and adults after introgression, as F(1) generation admixed panthers ( = 0·98) survived better than pre-introgression type panthers ( = 0·77) and other admixed individuals ( = 0·82). Furthermore, heterozygosity was higher for admixed panthers relative to pre-introgression type panthers and positively influenced survival. 5. Our results are consistent with hybrid vigour; however, extrinsic factors such as low density of males in some areas of panther range may also have contributed to higher survival of F(1) panthers. Regardless, improved survival of F(1) subadults and adults likely contributed to the numerical increase in panthers following introgression, and our results indicate that intentional admixture, achieved here by releasing individuals from another population, appears to have been successful in improving demographic performance in this highly endangered population.     

Natal Den Selection by Florida Panthers

ABSTRACT Information regarding habitat types selected by federally endangered Florida panthers (Puma concolor coryi) at natal den sites is needed because habitats used for parturition and kitten rearing potentially influence fitness of individuals and viability of the population. We located 51 natal den sites of 30 female panthers and performed a Euclidean distance analysis to determine which habitat types were selected and avoided at dens in south Florida, USA. Panther dens were closer to upland hardwoods, pinelands, and mixed wet forests (P ≤ 0.003) and farther from freshwater marsh-wet prairie (P = 0.009). We recommend that habitat protection efforts prioritize blocks of land that have abundant patches of upland hardwood, pinelands, and mixed wet forests to maintain preferred panther denning habitat.     

Roles of maternal condition and predation in survival of juvenile Elk in Oregon

Abundant evidence supports the benefits accrued to the Florida panther (Puma concolor coryi) population via the genetic introgression project implemented in South Florida, USA, in 1995. Since then, genetic diversity has improved, the frequency of morphological and biomedical correlates of inbreeding depression have declined, and the population size has increased. Nevertheless, the panther population remains small and isolated and faces substantial challenges due to deterministic and stochastic forces. Our goals were 1) to comprehensively assess the demographics of the Florida panther population using long-term (1981–2015) field data and modeling to gauge the persistence of benefits accrued via genetic introgression and 2) to evaluate the effectiveness of various potential genetic management strategies. Translocation and introduction of female pumas (Puma concolor stanleyana) from Texas, USA, substantially improved genetic diversity. The average individual heterozygosity of canonical (non-introgressed) panthers was 0.386 ± 0.012 (SE); for admixed panthers, it was 0.615 ± 0.007. Survival rates were strongly age-dependent (kittens had the lowest survival rates), were positively affected by individual heterozygosity, and decreased with increasing population abundance. Overall annual kitten survival was 0.32 ± 0.09; sex did not have a clear effect on kitten survival. Annual survival of subadult and adult panthers differed by sex; regardless of age, females exhibited higher survival than males. Annual survival rates of subadult, prime adult, and old adult females were 0.97 ± 0.02, 0.86 ± 0.03, and 0.78 ± 0.09, respectively. Survival rates of subadult, prime adult, and old adult males were 0.66 ± 0.06, 0.77 ± 0.05, and 0.65 ± 0.10, respectively. For panthers of all ages, genetic ancestry strongly affected survival rate, where first filial generation (F1) admixed panthers of all ages exhibited the highest rates and canonical (mostly pre-introgression panthers and their post-introgression descendants) individuals exhibited the lowest rates. The most frequently observed causes of death of radio-collared panthers were intraspecific aggression and vehicle collision. Cause-specific mortality analyses revealed that mortality rates from vehicle collision, intraspecific aggression, other causes, and unknown causes were generally similar for males and females, although males were more likely to die from intraspecific aggression than females. The probability of reproduction and the annual number of kittens produced varied by age; evidence that ancestry or abundance influenced these parameters was weak. Predicted annual probabilities of reproduction were 0.35 ± 0.08, 0.50 ± 0.05, and 0.25 ± 0.06 for subadult, prime adult, and old adult females, respectively. The number of kittens predicted to be produced annually by subadult, prime adult, and old adult females were 2.80 ± 0.75, 2.67 ± 0.43, and 2.28 ± 0.83, respectively. The stochastic annual population growth rate estimated using a matrix population model was 1.04 (95% CI = 0.72–1.41). An individual-based population model predicted that the probability that the population would fall below 10 panthers within 100 years (quasi-extinction) was 1.4% (0–0.8%) if the adverse effects of genetic erosion were ignored. However, when the effect of genetic erosion was considered, the probability of quasi-extinction within 100 years increased to 17% (0–100%). Mean times to quasi-extinction, conditioned on going quasi-extinct within 100 years, was 22 (0–75) years when the effect of genetic erosion was considered. Sensitivity analyses revealed that the probability of quasi-extinction and expected time until quasi-extinction were most sensitive to changes in kitten survival parameters. Without genetic management intervention, the Florida panther population would face a substantially increased risk of quasi-extinction. The question, therefore, is not whether genetic management of the Florida panther population is needed but when and how it should be implemented. Thus, we evaluated genetic and population consequences of alternative genetic introgression strategies to identify optimal management actions using individual-based simulation models. Releasing 5 pumas every 20 years would cost much less ($200,000 over 100 years) than releasing 15 pumas every 10 years ($1,200,000 over 100 years) yet would reduce the risk of quasi-extinction by comparable amount (44–59% vs. 40–58%). Generally, releasing more females per introgression attempt provided little added benefit. The positive effects of the genetic introgression project persist in the panther population after 20 years. We suggest that managers contemplate repeating genetic introgression by releasing 5–10 individuals from other puma populations every 20–40 years. We also recommend that managers continue to collect data that will permit estimation and monitoring of kitten, adult, and subadult survival. We identified these parameters via sensitivity analyses as most critical in terms of their impact on the probability of and expected times to quasi-extinction. The continuation of long-term monitoring should permit the adaptation of genetic management strategies as necessary while collecting data that have proved essential in assessing the genetic and demographic health of the population. The prospects for recovery of the panther will certainly be improved by following these guidelines. © 2019 The Authors. Wildlife Monographs published by Wiley Periodicals, Inc. on behalf of The Wildlife Society.     

Cysticerci (Cestoda: Taeniidae) from white-tailed deer, Odocoileus virginianus, in southern Florida

Metacestodes (cysticerci) of Taenia omissa Lühe, 1910, and Taenia hydatigena Pallas, 1776, were found in 9 and 1 of 124 white-tailed deer, respectively, in southern Florida in 1984-1986. Intensities of T. omissa varied from 1 to 15 (mean = 4.6); only 1 cysticercus of T. hydatigena was collected. No significant difference in the prevalences of T. omissa according to sex, age, or locality was observed.     

Does genetic introgression improve female reproductive performance? A test on the endangered Florida panther

Genetic introgression has been suggested as a management tool for mitigating detrimental effects of inbreeding depression, but the role of introgression in species conservation has been controversial, partly because population-level impacts of genetic introgressions are not well understood. Concerns about potential inbreeding depression in the endangered Florida panther (Puma concolor coryi) led to the release of eight female Texas pumas (P. c. stanleyana) into the Florida panther population in 1995. We used long-term reproductive data (1995–2008) collected from 61 female Florida panthers to estimate and model reproduction probability (probability of producing a litter) and litter size, and to investigate the influence of intentional genetic introgression on these parameters. Overall, 6-month probability of reproduction (±1SE) was 0.232 ± 0.021 and average litter size was 2.60 ± 0.09. Although F₁ admixed females had a lower reproduction probability than females with other ancestries, this was most likely because kittens born to F₁ females survive better; consequently, these females are unavailable for breeding until kittens are independent. There was no evidence for the effect of ancestry on litter size or of heterozygosity on probability of reproduction or litter size. In contrast, earlier studies have shown that genetic introgression positively affected Florida panther survival. Our results, along with those of earlier studies, clearly suggest that genetic introgression can have differential effects on components of fitness and highlight the importance of examining multiple demographic parameters when evaluating the effects of management actions.     

Helminths of the ocelot from southern Texas

In the USA, the ocelot (Leopardus pardalis) is a highly endangered felid found only in a few remaining vestiges of native thornshrub brushland in the Lower Rio Grande Valley (LRGV) of extreme southern Texas. From 1987-1998, carcasses of 15 adult ocelots that died of vehicular accidents or natural causes were examined for helminths. All cats had 1-8 (mean = 3) helminth species. All were infected with 1-101 (mean +/- SE = 32 +/- 7) Toxascaris leonina. Other helminths from these ocelots were Alaria marcianae, Brachylaima sp., Mesocestoides lineatus, Taenia rileyi, Oncicola canis, Dirofilaria immitis, Physaloptera rara, Ancylostoma tubaeformae, Cylicospirura chevreuxi, Vogeloides felis, and Metathelazia californica. Additionally, two cats had scarring of the aorta with lesions typical of those caused by Spriocerca lupi, although larval nematodes were not seen. A clinal variation in size of nearly three orders of magnitude was noted in the diplostomatid trematodes in the small intestine of one adult male ocelot. Despite the differences in size, all specimens appeared morphologically identical and were regarded as A. marcianae. Helminth prevalences and abundances, including those of potentially pathogenic species like D. immitis, were low. Although a single heartworm infection may have contributed to the death of one ocelot, helminth infections in general seemed to be of no great consequence to this endangered ocelot population. The helminth fauna of ocelots in the LRGV is reflective of that from wild felids in general; all have been reported previously from the bobcat (Lynx rufus) and mountain lion (Puma concolor) elsewhere in Texas.     

Prevalence of Bartonella henselae antibody in Florida panthers

Serum samples from 28 free-ranging Florida panthers (Puma concolor coryi) and seven mountain lions from Texas (P. concolor stanleyana) living in south Florida (USA) between 1997 to 1998 were tested for antibodies to Bartonella henselae. Twenty percent (7/35) of the samples were reactive to B. henselae antisera with a subspecies prevalence of 18% (5/ 28) for Florida panthers and 28% (2/7) for cougars from Texas (USA). There was not a significant sex related difference in infection rates among the Florida panthers. Antibody prevalence was higher in panthers <2-yr of age (40%) compared to panthers >2-yr (13%). Compared to studies of antibody prevalence in mountain lions (P. concolor) from California (USA), overall seroprevalence was lower as was prevalence in panthers >2-yr-old. However, the seroprevalence in animals <2-yr from southern Florida was similar to prevalences reported in mountain lions or domestic felids in California.     

Molecular detection and characterization of Cytauxzoon felis and a Babesia species in cougars from Florida

Piroplasms, morphologically indistinguishable from Cytauxzoon felis, previously were detected in 36% of cougars in Florida. We utilized a nested 18S rRNA assay, which amplifies DNA from all piroplasms, to screen blood samples collected from 41 cougars from Florida (39 native Florida panthers [Puma concolor coryi] and two translocated Texas cougars [P. c. stanleyana]) from 1989-2005. Thirty-nine of the 41 cougars (95%) were positive for piroplasms; however, sequence analysis and restriction enzyme digestion revealed that only five were positive for C. felis. Samples from 32 cougars were positive for a Babesia sp. Two cougars were co-infected with both C. felis and the Babesia sp. Phylogenetic analysis of 18S rRNA gene sequence indicated that the Florida panther Babesia sp. was most closely related to a Babesia sp. reported from Ixodes ovatus from Japan, Babesia divergens, and Babesia odocoilei. This study indicates that Florida panthers harbor two distinct piroplasms, C. felis and a Babesia sp., and that some individuals are infected with both organisms. The infectivity and pathogenicity of this Babesia sp. for domestic cats is unknown. This represents the first report of a feline Babesia sp. in North America.     

Parasitic helminths of Eurasian collared-doves (Streptopelia decaocto) from Florida

Sixty-three Eurasian collared-doves (ECDs) (Streptopelia decaocto) from Florida were examined for parasitic helminths from June to December 2001. Nine species of helminths were identified (5 nematodes, 2 cestodes, and 2 trematodes). The most prevalent helminths were Ascaridia columbae (73.0%), Fuhrmannetta crassula (28.6%), Ornithostrongylus quadriradiatus (12.7%), and Bruscapillaria obsignata (11.1%). The helminths with the greatest mean intensity were Tanaisia bragai (13.5), A. columbae (9.3), and O. quadriradiatus (7.1). In Florida, the mean intensity of A. columbae in ECDs (9.3) was similar to that found in white-winged doves (Zenaida asiatica) (9.1) (P = 0.461), and both the intensities were significantly higher than that in the native mourning doves (Zenaida macroura) (3.7) (P = 0.001 and 0.005, respectively). Fuhrmannetta crassula is reported for the first time in columbids from Florida.     

Hematologic effects of cytauxzoonosis in Florida panthers and Texas cougars in Florida.

Cytauxzoon felis is a long-recognized hemoparasite of free-ranging Florida panthers (Puma concolor coryi), but its prevalence and effect on the population has not been assessed. Red blood cell indices and white blood cell counts were compared between infected and noninfected Florida panthers and Texas cougars (Puma concolor stanleyana) from 1983-1997 in Florida (USA). The prevalence of cytauxzoonosis for both populations was 39% (11/28) for Texas cougars, 35% for Florida panthers (22/63) and 36% overall. Thirteen hematologic parameters were compared between C. felis positive and negative panthers and cougars. Florida panthers had significantly lower mean cell hemoglobin count (MCHC) and higher white blood cell (WBC), neutrophil, monocyte and eosinophil counts (P < or = 0.05) than Texas cougars. Infected Florida panthers had significantly lower mean cell hemoglobin (MCH) and monocyte counts and higher neutrophil and eosinophil counts than infected Texas cougars. Although statistically significant differences were measured for hematologic parameters in C. felis positive panthers and cougars, biologically significant differences were not likely because values were generally within expected reference ranges for healthy animals. Cytauxzoonosis does not appear to have a negative effect on the hematologic parameters of chronically infected panthers and cougars. Potential transient changes during initial infection were not evaluated.     

Transmission of Ancylostoma caninum and Alaria marcianae in coyotes (Canis latrans)

One of seven female coyotes (Canis latrans) captured in Webb County, Texas during September 1986 and confined and mated in holding facilities at Millville, Utah whelped the following spring. The maternal female (greater than 5-yr-old) and her five neonates were killed at 22 days postparturition. All were infected with adult Ancylostoma caninum and were passing eggs in their feces. Also, the neonates and maternal female were infected with immature and adult Alaria marcianae, respectively. These findings suggested that the transmammary route is an important transmission mechanism for acquisition of these species of helminths in coyotes. The lack of overdispersion in the frequency distribution of these parasites and infection of the entire litter indicated that transmission from the infected female was nonselective among the pups.     

The genetic rescue of the Florida panther

We examine the consequences of panthers introduced from Texas into south Florida, an area housing a small, isolated, inbred and distinct subspecies ( Puma concolor coryi ). Once part of a continuous, widespread population, panthers became isolated in south Florida more than a century ago. Numbers declined and the occurrence of genetic defects increased. Hoping to reverse the genetic damage, managers introduced eight female panthers from Texas into south Florida in the mid-1990s. This action was highly controversial and we explain the arguments for and against the intervention. We synthesized data systematically collected on the Florida panthers from before, during and after this management intervention. These data include information on movements, breeding, mortality, survivorship and range. There is no evidence that purebred Florida females produce fewer kittens at a later age or less often than do hybrid cats (i.e. those with a Texas ancestor). Hybrid kittens have about a three times higher chance of becoming adults as do purebred ones. Hybrid adult females survive better than purebred females; there is no obvious difference between the males. Males die younger than females, are more often killed by other males and are more likely to disperse longer distances into habitats that are dangerous to them. Hybrids are expanding the known range of habitats panthers occupy and use.