Desert Lions

History

Demography

Habitat

Socio-ecology

Behaviour

Dispersal

Historical records of lions in the Skeleton Coast Park

Records of lions inhabiting the northern Namib and along the Skeleton Coast are well documented in the literature. In 1934 Shortridge (1934) observed that lions were common in the coastal regions, mountains, and ephemeral rivers, between the lower Kuiseb River and the Kunene River. In the Kaokoveld and along the Kunene valley, however, Shortridge believed them to be plentiful (Figure 2). The Skeleton Coast Park was proclaimed in 1967 and sporadic sightings of lions were recorded. Bridgeford (1985) observed lions foraging along the beaches, eating seals and cormorants, and in 1984 Steve Braine photographed a male lion feeding on a beached whale (photo).

Photo by Steve Braine - 1984

Figure 2. The distribution of lions in Namibia in 1934, after Shortridge (1934).

Conservation officials, employed by the Ministry of Environment and Tourism (previously Department of Nature Conservation) kept good records of game counts and patrols in the Skeleton Coast Park. Early records were recorded on “punch-cards” (Figure 3) and more recent observations had been captured on a database. The Park Warden (J Patterson) kindly made both the electronic data set and the old “punch-cards” available for analysis.

Figure 3. Example of “punch-cards” completed by conservation officials.

Table 1. A list of the people that recorded lions in the Skeleton Coast Park between 1970 -1991.

Between 1970 and 1991 (22 years), there were 238 observations of lions and a total 477 lions were recorded (Table 1). The frequency of sightings was highest during the 1980s (Figure 4), with an average of 18 sightings per year (range: 5-37). It was not possible to control for the potential bias associated with variable effort between years. As a result, the substantial peak in the number of sightings during the 1980s may partly be a function of increased patrol effort and vigilance by Park staff, instead of an increase in the number of lions.

Figure 4. The number of lion observations in the Skeleton Coast Park between 1970 and 1999.

Figure 5. Average group size of lions observed in the Skeleton Coast Park between 1974 and 1999. (Error bars indicate the minimum / maximum range)

Overall the average group size of lions observed is 2.1 lions (SD = 1.61, range 1-9). The mean annual group size, however, appears to decline between 1974 and 1991 (Figure 5). This may suggest a steady decline in the size of the lion population when considering the Resource Dispersion Hypothesis (Macdonald 1983), where group size is a function of food richness. The age structures of lions indicate mainly adult lions, but the records suggest three birth peaks during the 1980s (Figure 6). The preponderance of cubs during observations in 1984 and 1988 is followed by and increase in sub-adults two years later, lending credibility to the data set. The sex ratios of observations suggest an unusual abundance of females (Figure 7). Observations of lions in the Skeleton Coast Park were most common during the dry season (May – October; Figure 8) when prey animals generally concentrate along the ephemeral river systems.

Figure 6. The average age structure per year of lions observed in the Skeleton Coast Park between 1979 and 1991.

Figure 7. The average sex ratio per year of lions observed in the Skeleton Coast Park between 1980 and 1990.

Figure 8. The monthly frequency of lion observations in the Skeleton Coast Park between 1970 and 1999. (Red line indicate the expected frequency).

The distribution of observations shows that lions were recorded throughout the Skeleton Coast Park (Figure 9). Lions were most regularly seen in the Hoanib River. The southern river systems (Ugab, Huab, Koigab, & Uniab Rivers) produced consistent sightings throughout the 22-year period. Observations in the northern rivers (Hoaruseb, Khumib, Secumib, Nadas, Munutum Rivers) declined towards the end on the 1980s. It is interesting to note that a single lion was recorded at the mouth of the Kunene River in 1983 (2 observations) and then again in 1989.

Figure 9. The distribution of lion sightings during 8 periods in the Skeleton Coast Park, between 1970 and 1991.

1970 - 1975
1976 - 1980
1981 - 1982
1983 - 1984

1985 - 1986

1987 - 1988

1989 - 1990

1991 - 1999

Last data analysis & update - March 2007