# Spoor density as a measure of true density of a known population of free-ranging wild cheetah in Botswana

> Can you count cheetahs by their tracks? In a Botswana game reserve where every cheetah was known, researchers drove more than 8000 km of sandy roads counting spoor and compared it with the real population. Track counts underestimated the cheetahs, and a correction that worked in one wet season overshot the next, showing how rain, prey and cubs change the way cheetahs leave their tracks.

Summary by Kersey Lawrence, Original Wisdom. Updated 9 November 2026. Page: https://www.originalwisdom.com/tracking-literature/2009-houser-somers-spoor-density-measure-true/

## Citation and access

- **Authors:** A. M. Houser, M. J. Somers and L. K. Boast
- **Year published:** 2009
- **Journal or source:** Journal of Zoology
- **Full citation:** Houser, A. M., Somers, M. J. and Boast, L. K. 2009. Spoor density as a measure of true density of a known population of free-ranging wild cheetah in Botswana. Journal of Zoology 278(2): 108–115.
- **DOI:** 10.1111/j.1469-7998.2009.00554.x
- **Access status:** Publisher link only
- **Where to find it:** https://doi.org/10.1111/j.1469-7998.2009.00554.x

## Tags

- **Species:** Mammals > Brown hyena; Mammals > Cheetah; Mammals > Domestic dog; Mammals > Leopard
- **Region:** Africa > Botswana
- **Tracking:** Individual identification; Track counts; Tracking; Tracks; Tracks and signs identification; Trailing
- **Behaviour and ecology:** Behaviour; Movement
- **Methods and technology:** Analysis of variance (ANOVA); Bootstrapping; Direct observation; Double sampling; Global Positioning System (GPS) collars; Kolmogorov–Smirnov test; Linear regression; Pearson correlation; Population estimation; Radio telemetry; Road transects; Simulation
- **Data type:** New field data
- **Observer qualification:** Reported but not validated
- **Discipline:** Behaviour and ecology; Wildlife tracking
- **Year published:** 2009

## Detailed keywords

- **Species:** Studied: cheetah (Acinonyx jubatus), a known population of two collared or ear-tagged families (F5 and F6) plus unidentified individuals. Other large predator spoor recorded on the transects: leopard (Panthera pardus), brown hyena (Hyaena brunnea) and domestic dog (Canis lupus familiaris). Black-backed jackal (Canis mesomelas) named as one of the reserve’s main predators. Prey counted: blue wildebeest (Connochaetes taurinus), zebra (Equus burchelli), warthog (Phacochoerus africanus), ostrich (Struthio camelus) and all antelope species except eland (Tragelaphus oryx). Species mentioned from other spoor studies: lion, wild dog, spotted hyena, caracal, mountain lion, tiger, black rhino.
- **Location and habitat:** Jwana Game Reserve, Jwaneng, southern Botswana (24°33′09.3″S, 024°43′38.0″E). Study area 180.31 km², plus 32.62 km² of the fenced Debswana Diamond Mine, which was assumed to be little used. Game-fenced, but predators move freely through warthog holes and under fences; surrounded by cattle posts, with Jwaneng city centre 5 km south of the mine. Flat sandveld of open semi-wooded savannah with moderate to thick bush (Acacia mellifera, Acacia luedritzii (as spelled in the paper), Boscia albitrunca); desert sand soils; sandy roads with two calcrete main roads; no lions or spotted hyenas. Rainfall 581 mm in 2006.
- **Topics:** spoor surveys as an index of abundance; calibrating spoor density against true density (double sampling); correction factor; road penetration (sample intensity); sample effort; spoor frequency; seasonal differences in cheetah movement and road use; cheetah family groups spreading out up to 50 to 100 m apart; open population with breeding females and cubs; prey density; rainfall effects. Inconsistencies in the paper: (1) the trend line equations in the text (wet season y = 0.403x − 0.071; dry season y = 0.569x − 0.406; both wet seasons y = 1.450x + 0.676) do not match those in Figure 5 (wet 1 y = 0.4029x + 0.0713; dry y = 0.5934x − 1.0268; wet 2 y = 0.5692x + 0.4058; wet 1 and 2 y = 0.6455x − 0.2864); the text’s dry season equation matches the figure’s second wet season line; (2) the paper does not show how the predicted 10.84 cheetahs per 100 km² was worked out from the wet season equation; (3) Figure 5’s true density axis runs only to 4.5, while Table 1 gives true densities of 3.33 to 8.89 per 100 km²; (4) the abstract gives spoor density as 2.32 per 100 km², the results as 2.32 per 100 km of road; (5) the abstract and survey design put the dry season at April to September, the study area description at April to October (wet season November to March); (6) the population is said to have been monitored since November 2003 in one place and October 2003 in another; (7) the paper calls the wet and dry season relationships linear, but neither was statistically significant (P = 0.147 and P = 0.121).
- **Statistics or models:** Spoor frequency (km per individual spoor) and spoor density (spoor per 100 km), after Stander (1998); Monte Carlo resampling with 1000 replicates (a form of bootstrap analysis) in PopTools 2.7.5 to set sample intensity; coefficient of variation (CV) to set sample effort; Kolmogorov–Smirnov test for normality; Pearson correlation; one-way analysis of variance (ANOVA) with post hoc tests between transects; linear trend lines (regression) of true density against spoor density; SPSS 11.0.1.
- **Data type:** New field data: spoor survey October 2005 to September 2006 (first wet season October 2005 to March 2006; dry season April to September 2006), with a test season October to December 2006. Cheetah population monitored since 2003 by radio telemetry, GPS cell collars and sightings. Prey counts March to December 2006.

## Synopsis

### 1. What they did

Counting tracks along roads is a cheap and practical way to monitor large carnivores, but spoor counts only give a relative index. To turn them into a real density, the index has to be calibrated against a population whose true size is known. Earlier work had done this for lion, leopard and wild dog, but not for cheetah, whose home ranges, daily movements and road use differ.

The authors did this in Jwana Game Reserve, southern Botswana, where the cheetah population had been monitored since 2003:

- Knowing the true population. Cheetahs were caught in box traps, ear-tagged, microchipped and photographed so they could be recognised by their spots. One female (F5) wore a cell collar that sent Global Positioning System (GPS) locations one to four times a day. A second family (F6) was seen about every 12 days. On average 89% of cheetahs present each month were known individuals. Researchers, game park staff and tourist photographs accounted for the rest. Spoor that seemed to belong to a new animal was followed to try to see and trap it.

- The spoor survey. The reserve was split into four sections with three 9 km transects each (12 transects, 108 km). One transect per section was driven each day, so each was left at least 48 hours between surveys. One or two four-wheel-drive vehicles drove at 8 to 12 km per hour from one hour after sunrise until 11:30. The roads were not swept beforehand. All large predator spoor was recorded, with a minimum of two people per vehicle. Each cheetah counted as a separate spoor, even when walking in a family group, and each animal was counted only once a day.

- Calibrating and testing. They compared spoor density with true density for the first wet season (October 2005 to March 2006) and the dry season (April to September 2006). They did this for one family, for two families and for all cheetahs. They then used a second wet season (October to December 2006) to test the wet season correction factor.

- Prey counts. From March to December 2006 an extra observer counted prey animals seen from the transects.

### 2. What they found

Survey effort

- 8226 km were driven, and 191 individual cheetah spoor were found: one spoor every 43.07 km, or 2.32 spoor per 100 km.

- There was no significant difference in spoor frequency between transects, although some were driven about twice as often as others.

- Results became reliable once there was at least 1 km of road surveyed for every 3.34 km² of study area.

- In the wet season about 38 spoor (1296 km of driving) gave a precise and accurate result. The dry season needed about 90 spoor (3636 km). The second wet season needed 50 spoor (864 km).

True density versus spoor density

- True density averaged 5.23 cheetahs per 100 km². It ranged from 3.33 to 7.78 and rose from 3.80 in the wet season to 6.67 in the dry season, when one female’s five cubs joined the counts.

- Spoor density also rose, from 1.45 spoor per 100 km in the wet season to 3.10 in the dry season.

- Spoor density was lower than true density in both seasons, unlike earlier lion and leopard studies, where spoor overestimated density.

- Trend lines linked spoor and true density in both seasons, but neither was statistically significant on its own.

The test

- In the second wet season spoor density was 4.44 per 100 km. The first wet season correction factor predicted 10.84 cheetahs per 100 km², but the true density was 7.22. The correction factor overestimated the population.

- Spoor counts rose by 306% while true density rose by only 190%. The first wet season had 364 mm more rain than the second.

- Combining both wet seasons gave a significant relationship between spoor and true density (r = 0.968, P = 0.002).

Prey and movement

- Prey density was 52 animals per km² in the wet season and 21 per km² in the dry season.

- Collar data showed female F5 used a larger area and spent more time outside the reserve in the dry season.

- The two main families followed a regular cycle: each month they overlapped in one area for up to a week, then moved to different parts of the park.

- Cheetahs in families and coalitions did not walk in a line along roads. They often spread out up to 50 to 100 m apart.

### 3. What they concluded

- A measurable relationship between spoor density and true density exists for cheetahs, separately for wet and dry seasons. Spoor counts underestimated the population.

- The authors suggest the underestimate may be because family members spread out, so all of them are rarely on the road at the same time. The differences from lion and leopard studies may be species related.

- The dry season needs more sampling. In the wet season, cheetahs may stay in smaller areas, with taller grass for stalking and thick bush for resting. In the dry season, prey moves to find water, so cheetahs may need to travel further and use a larger area.

- The wet season correction factor had to be revised with the second wet season’s data. Rainfall changed the habitat and water points, which may have changed prey movements and how cheetahs behaved and used roads.

- Limitations: a small study area, few animals, and an open population with breeding females. Cubs arriving and sub-adults and females leaving may have changed spoor density, so studies need to run long enough not to underestimate the population. The dry season line could not be tested with a second dry season.

- Spoor surveys with correction factors can work for long-term monitoring, but should be used with caution. Calibration studies need repeating many times so the correction factor captures changes in season, habitat, prey and behaviour.

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

Tracking was the core of the study. Teams drove sandy roads and identified the spoor of cheetah, leopard, brown hyena and domestic dog. Where possible they identified individual cheetahs from their spoor, using group size, cub age, known GPS locations and, for one family (F6), the females’ distinctive round hind feet. Spoor thought to come from a new cheetah was followed to try to see and trap the animal. The paper does not describe how cheetah spoor was told apart from leopard or other spoor.

### 5. Tracker or observer certification

Reported but not validated. Spoor was identified by “trained researchers”. The lead researcher had three years of experience in spoor tracking, and trained and tested the other researchers on spoor identification. No certification, test method or test results are reported. Staff members thanked in the acknowledgements guided international volunteers on the daily spoor surveys. The authors accept there may have been some errors in spoor detection and identification.

### 6. Other technologies, skills or innovations

- GPS cell collar on one female, radio telemetry, ear tags and microchip transponders, and spot-pattern identification from photographs, including tourists’ photographs.

- Double-ended box traps with live bait in a separate holding cage.

- Monte Carlo resampling in PopTools (an Excel add-in) to decide how much road to survey for a reliable spoor frequency.

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

- Cheetahs were listed as vulnerable, and like most large carnivores their numbers are declining, so accurate, repeatable and affordable ways to measure population trends and density are needed.

- Spoor surveys are less invasive and cheaper than direct methods and suit low-density species such as cheetah, but they need a correction factor to give true density.

- Correction factors must be tested and refined over time, because animals change their behaviour with season, habitat and prey.

- Cheetah density here was higher than in a Kgalagadi Transfrontier Park spoor study, perhaps partly because there were no lions or spotted hyenas. Cheetahs are known to survive better outside protected areas, where there is less competition from these large predators.

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

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

- The study shows how much behaviour shapes a track count: the same cheetahs left very different amounts of spoor on the roads depending on rain, prey and whether cubs were present. A tracker’s knowledge of how animals use roads in different seasons matters as much as the count itself.

- Identifying spoor to individual cheetahs (here helped by one family’s distinctive round hind feet) linked tracks to known animals, which is what made the calibration possible.

- Observer skill was described but not tested in a reported way. Formal evaluation of the trackers would make results like these easier to compare with other spoor studies.

## Cite this summary

Lawrence, K. 2026. Summary of: Spoor density as a measure of true density of a known population of free-ranging wild cheetah in Botswana (Houser and Somers et al., 2009). Original Wisdom, Tracking Literature. https://www.originalwisdom.com/tracking-literature/2009-houser-somers-spoor-density-measure-true/