Table 4.
Potential mammalian predators (cat, fox, and pig) and antagonists (herbivorous ungulates) of rattlesnakes on Santa Catalina Island (194 km2), California, USA, including dates for introduction to and removal from the island, and highest historical population estimates (N) and density (island-wide N/km2). a All are introduced species with the possible exception of the fox.
| Species | Introduction | Removal | Highest N | Highest Density | Distribution | Source |
|---|---|---|---|---|---|---|
| Cat (Felis catus) | 1800s | extant | 600–750 | 3.1–3.9 | island-wide | [69] |
| Island fox (Urocyon littoralis catalinae) |
7100–9200 years ago | extant | 1115–1342 | 5.7–6.9 | island-wide | [70,71,72] |
| Pig (Sus scrofa) | early 1930s | 2004 | 1260–5000 | 6.5–25.8 | island-wide | [73,74,75,76] |
| American bison (Bison bison) | 1924 | extant | 400–524 | 2.1–2.7 | currently east end | [76,77,78,79] |
| Black buck (Antilope cervicapra) |
1967–1973 (uncertain) |
2014 | <25 | ~0.1 | east end | [80,81,82] |
| Cattle (Bos taurus) | 1800s | 1950s | >5225 | 26.9 | island-wide | [76,78,83] |
| Goat (Capra hircus) | early 1800s | 2003 | 30,000–50,000 | 154.6–257.7 | island-wide | [76,84,85,86] |
| Horse (Equus caballus) | 1800s | unknown | 240 | 1.2 | unknown | [76] |
| Mule deer (Odocoileus hemionus) |
1928 | extant | 2000–3285 | 5.4–16.9 | island-wide | [76,87,88] |
| Sheep (Ovis aries) | 1800s | 1920s | 22,000 | 113.4 | island-wide | [76,78,86] |
a Domestic dogs (Canis lupus familiaris) were likely common at one time [62], but currently exist in human residential areas without a substantial feral population.