# Competition and coexistence in sympatric bobcats and pumas

> Do bobcats steer clear of pumas? In the Huachuca Mountains of Arizona, a study built on tracks and scats found bobcats active in every habitat whether or not pumas had passed, but their diets told another story. Bobcats ate mostly rabbits and rodents, pumas mostly deer, and one puma scat held the remains of a bobcat.

Summary by Kersey Lawrence, Original Wisdom. Updated 9 November 2026. Page: https://www.originalwisdom.com/tracking-literature/2009-hass-competition-coexistence-sympatric-bobcats/

## Citation and access

- **Authors:** Christine C. Hass
- **Year published:** 2009
- **Journal or source:** Journal of Zoology
- **Full citation:** Hass, C. C. 2009. Competition and coexistence in sympatric bobcats and pumas. Journal of Zoology 278(3): 174–180.
- **DOI:** 10.1111/j.1469-7998.2009.00565.x
- **Access status:** Publisher link only
- **Where to find it:** https://doi.org/10.1111/j.1469-7998.2009.00565.x

## Tags

- **Species:** Mammals > Bobcat; Mammals > Mountain lion
- **Region:** North America > United States
- **Tracking:** Scat; Sign surveys; Track counts; Tracking; Tracks; Tracks and signs identification
- **Behaviour and ecology:** Behaviour; Carnivore coexistence; Competition; Feeding; Interspecific competition; Intraguild interactions; Predation
- **Methods and technology:** Bootstrapping; Global Positioning System (GPS)
- **Data type:** New field data
- **Observer qualification:** Not reported
- **Discipline:** Behaviour and ecology; Wildlife tracking
- **Year published:** 2009

## Detailed keywords

- **Species:** Studied: bobcat (Lynx rufus) and puma (Puma concolor). Prey found in scats: cottontails (Sylvilagus spp., printed “Syvilagus” in the text), jackrabbits (Lepus spp.), deer (Odocoileus hemionus and Odocoileus virginiana, identified only to genus), peccary (Pecari tejacu, as spelled in the paper), coati (Nasua narica), hog-nosed skunk (Conepatus leuconotus), Mephitis skunks (Mephitis mephitis and Mephitis macroura), spotted skunk (Spilogale gracilis), ringtail (Bassariscus astutus), turkey (Meleagris gallopavo), rock squirrel (Spermophilus variegatus), gray squirrel (Sciurus arizonensis), pocket gophers (Thomomys spp.), woodrats (Neotoma spp.), cotton rats (Sigmodon spp.), small rodents (Peromyscus spp., Baiomys taylori and Reithrodontomys spp.), small birds and snakes. A bobcat was found in one puma scat, and juvenile puma remains in puma scats. Likely scavenged and excluded: cow (Bos taurus) hair in one bobcat scat, black bear (Ursus americanus) hair in one puma scat. Other felids discussed from the literature: African golden cat, leopard, jaguar, cheetah and lion.
- **Location and habitat:** In and near the Huachuca Mountains, about 130 km south-east of Tucson, Arizona, United States: Fort Huachuca Military Reservation, Coronado National Forest and San Pedro Riparian National Conservation Area (about 300 km²). Riparian forest, grassland, savanna, mesquite bosque and desert scrub at about 1400 m, and Madrean oak and pine woodland up to 2800 m. The region meets the northern end of the Sierra Madre and the southern end of the Rocky Mountains.
- **Topics:** intraguild predation; interference competition; exploitative competition; carnivore coexistence; space use by habitat; spatial avoidance; diet composition, dietary niche breadth and dietary overlap; prey size; juvenile prey; scat analysis (hair, claws, teeth and bone fragments); sign surveys on transects; track sets per km as an activity index.
- **Statistics or models:** Track sets per km of transect as an activity index, with means and 95% confidence intervals from bootstrapping (10,000 resamples). Brillouin diversity index (Hb) with resampled diversity and incremental change curves to test whether enough scats were collected. Per cent occurrence of prey items. Levins dietary niche breadth, standardized by Hurlbert (Bs). Mean weight of vertebrate prey (MWVP, geometric mean). MacArthur and Levins dietary overlap index and Pianka’s composite overlap index, with bootstrapped 95% confidence intervals. Possible inconsistencies: (1) the Discussion says 89% of the puma diet was ungulates, but the Results say 89% was ungulates and small to medium carnivores together, and Table 2 and the Abstract give ungulates as 69%; (2) bobcat track rates with and without puma sign on the same survey are given with identical means and confidence intervals (0.28, 95% CI 0.13 to 0.60), which may be a copying error; (3) the study is dated 1997 to 2002 overall, while the transect surveys ran October 1998 to January 2000 (Figure 1 says 1998 to 2000).
- **Data type:** New field data. Sign surveys on 27 transects (90 surveys) from October 1998 to January 2000; scats collected 1997 to 2002 on the surveys and opportunistically during other field studies, with some puma scats collected by H. Shaw.

## Synopsis

### 1. What they did

Bobcats and pumas share much of western North America, and pumas are known to kill bobcats. Pumas are three to six times larger, so on body size alone the two cats should not compete much, yet both are known to eat prey ranging from small rodents to deer. The author asked whether pumas affect where bobcats are active, how their diets compare, and whether interference competition (one predator harming or killing another) shapes their relationship.

The study took place in and near the Huachuca Mountains of south-eastern Arizona, an area rich in prey and with 16 species of carnivores.

- Space use. Bobcat and puma tracks and scats were recorded on 27 transects along dirt roads and trails at Fort Huachuca and on loops along the San Pedro River, split by habitat: grassland, desert scrub, riparian forest and oak and pine woodland. Transects were 0.9 to 9.2 km long, and each was surveyed at least three times, at least 2 months apart, between October 1998 and January 2000. Sign was identified by comparison with published field guides and located with a Global Positioning System (GPS) receiver and a topographic map. Activity was measured as track sets per km.

- Diet. Felid scats were collected on these surveys and during other field studies from 1997 to 2002, identified by odour, size and shape, then washed through sieves. Hair, claws, teeth and bone fragments were identified against reference collections.

- Analysis. The author checked that enough scats had been collected, then compared the two cats’ diets: what they ate, how varied the diet was (niche breadth), the average weight of prey, and how much the diets overlapped.

### 2. What they found

Space use

- The 27 transects were surveyed 90 times. Sign of bobcats or pumas was found on all but one transect: bobcats only on 7, pumas only on 1, and both on 18 (67%). Both cats left sign on 30 of the 90 surveys (33%), in every habitat type.

- Bobcat activity was similar across all four habitats. Pumas were more active in riparian forest and woodland than in grassland or scrub.

- Bobcat activity was the same whether or not puma sign was found on the same survey (0.28 track sets per km).

Diet

- 61 bobcat scats held 96 prey items from 17 taxa; 64 puma scats held 73 items from 14 taxa. Both samples were large enough to describe the diet.

- Bobcats ate mainly rodents (33% of items) and lagomorphs such as cottontails and jackrabbits (32%), then ungulates (16%), birds and reptiles (10%) and carnivores (8%). Eight taxa each made up more than 5% of items: cottontails, deer, small rodents, small birds, rock squirrels, pocket gophers, jackrabbits and woodrats. Identifiable juvenile coatis, cottontails and deer made up 7% of the diet, a minimum because juveniles could not always be recognized.

- Pumas ate mainly ungulates (69%) and carnivores (21%). Deer alone made up 55% of the diet, and only deer, coatis and peccaries each made up more than 5%. Remains of a bobcat were found in one puma scat.

- Bobcats had a broader diet than pumas (standardized niche breadth 0.39 against 0.13). Their average vertebrate prey weighed 652 g, against 13,736 g for pumas.

- The bobcat diet overlapped the puma diet by 20%, but the puma diet overlapped the bobcat diet by 56%. The combined overlap was 36%.

### 3. What they concluded

- Bobcats showed little sign of avoiding pumas in space. They may avoid pumas at a finer scale or in time, which this study did not measure. With no data on prey availability, the author could not tell whether the habitat differences reflected preferred prey or avoidance.

- As expected, bobcats ate mostly rabbits and rodents and pumas mostly deer, consistent with earlier studies.

- Because pumas have a narrower diet that overlaps strongly with the bobcat diet, pumas may be more vulnerable than bobcats to changes in prey numbers, for example during drought. Bobcats eat many fast-breeding prey species.

- Bobcats can kill deer, and deer make up a large share of bobcat diets where pumas are absent or rare. Bobcats may kill fewer deer where pumas are present, to reduce the risk of being killed at a carcass.

- Pumas killed and ate bobcats, so interference competition may work through intraguild predation (one predator killing a competitor). The author hypothesizes that bobcats may adjust their foraging or diet to reduce this risk, but could not rule out that their diet and habitat use simply reflected the prey available.

- More studies in other habitats and conditions, including more competitors and prey availability, are needed.

### 4. How tracking was or was not used

Tracking was central to the study. Space use rested entirely on sign surveys: bobcat and puma tracks and scats were found along transects, identified with published field guides, and counted as track sets per km to compare activity between habitats and between surveys with and without puma sign. The diet data came from felid scats identified in the field by odour, size and shape. No trailing was reported. The acknowledgements refer to this work as “the tracking study.”

### 5. Tracker or observer certification

Not reported. The paper does not say who identified the tracks and scats or how skilled they were, beyond comparison with published field guides (Murie 1975; Aranda Sanchez 1981; Rezendes 1999). M. Tuegel is thanked for field assistance and H. Shaw for collecting some puma scats. This matters because both the activity index and the diet comparison depend on telling bobcat and puma sign apart; scat identification was not confirmed with DNA.

### 6. Other technologies, skills or innovations

- Sign located with a GPS receiver and a United States Geological Survey (USGS) topographic map.

- Scat contents identified with microscopes, reference collections and a hair-mounting technique (Carter and Dilworth 1971).

- Resampled diversity curves (Brillouin index) to test whether enough scats had been collected.

### 7. Implications for conservation (from the paper)

- Pumas, with their narrow, deer-based diet, may be more vulnerable than bobcats to changes in prey numbers such as those caused by drought.

- Larger predators can shape the diets and behaviour of smaller ones by killing or intimidating them, effects that may extend to other levels of the food chain.

### 8. Implications for tracking (Original Wisdom's observations)

_These are Original Wisdom's observations, not the authors'._

- The study shows how much a sign survey can reveal about two species at once: tracks gave an index of where each cat was active, and scats gave their diets, including direct evidence that pumas ate a bobcat.

- Bobcat and puma tracks and scats differ mainly in size, and both data sets depend on separating them correctly. The paper does not report who identified the sign or how reliably, so the accuracy of the observers is unknown.

## Cite this summary

Lawrence, K. 2026. Summary of: Competition and coexistence in sympatric bobcats and pumas (Hass, 2009). Original Wisdom, Tracking Literature. https://www.originalwisdom.com/tracking-literature/2009-hass-competition-coexistence-sympatric-bobcats/