Horse
Depending on breed, management and environment, the modern domestic horse has a life expectancy of 25 to 30 years. Uncommonly, a few animals live into their 40s and, occasionally, beyond. The oldest verifiable record was "Old Billy", a 19th-century horse that lived to the age of 62. In modern times, Sugar Puff, who had been listed in "Guinness World Records" as the world's oldest living pony, died in 2007 at age 56.
Namib Desert Horse
The Namib Desert Horses were originally forced to compete with domesticated livestock turned loose by farmers onto the same ground where the horses grazed. Due in part to this competition for limited forage, the horses nearly became extinct. However, they were saved in part due to the efforts of Jan Coetzer, employee of Consolidated Diamond Mine (CDM or DBCM), mining in part of Sperrgebiet. Garub was a station for the re-filling of steam locomotives until 1977, when diesel locomotives took over the route. The horses, who had previously survived on water pumped for the locomotives, were placed in danger when the pumping stopped, with several horses dying of dehydration. Coetzer petitioned CDM to supply the horses with water, which they did in 1980, installing holding tanks and a water trough. Between 1964 and 1984, population estimates ranged between 50 and 200 horses, but generally averaged 140 to 160. In 1984, an aerial count was made that distinguished 168 horses, while ground-based observations in 1988 estimated between 150 and 200 animals.
In the mid-1980s, the horses' habitat was made part of Namib-Naukluft Park, the largest game reserve in Africa. In 1986, after the expansion to the park, a movement was made to remove all horses (which were considered an exotic species); public outcry prevented this from happening. The following year, 10 horses were removed from the park for research purposes and 8 others for use as patrol horses in Etosha National Park, although they were unsuccessful in the latter use. In 1992, as Namibia gained its independence and a drought enveloped southern Africa, a decision was made to reduce the population, then estimated at 276 animals. In June, 104 animals were captured unselectively and sold, but many did not adjust well to their new habitats and by 1997 at least half had died. In 1997, with the feral population at 149 horses, 35 horses, selected for age, gender and degree of genetic relationship, were removed, with the intent being to sell them at auction. The horses were kept in holding pens for six weeks, during which time the stallions became very aggressive and had to be separated; after this, the auction was cancelled and the horses released back to their range. Beginning in December 1993, semiannual population counts have been completed. Between 1993 and 2005, herd numbers ranged between 89 and 149 animals, with the 1999–2001 counts providing sub-100 population numbers. Although several attempts were originally made to exterminate the horses, due to a possible threat to oryx habitat, they are now protected by the South West Africa/Namibia Directorate of Nature Conservation. The Namib Desert Horse is likely the only herd of feral horses in Africa.
There is concern in some quarters that the horses are a negative influence on their habitat, through overgrazing and competition with native species. While exotic species, such as the Namib Desert Horse, are generally unwanted in the Namib-Naukluft Park, the horses are a special case, given their close ties with Namibian history, their popularity with visitors, and their appeal as subjects for case studies of feral horse bands. Studies during 2003 and 2004, however, found that while an area of approximately around the watering area at Garub has been affected by the horses, there was no significant disturbance of the area outside this radius. The amount and species of vegetation found outside the watering area appear more affected by rainfall then by the horses, probably due to the low population density and natural rotational grazing. Due to the lack of effect on vegetation by horses, it is unlikely that they significantly influence small mammal populations. The horses also appear to have no measurable effect on any vulnerable or endangered plant or animal species, which in several cases are more threatened by human influence. As the horses are restricted to a certain grazing area and native large herbivores are not, the horses do not pose a danger to the latter species. The horses in the Namib Desert were originally known by the local population as "ghost horses", as they mostly stayed away from human habitations and were rarely seen. However, when their grazing grounds were made part of the game reserve, a policy of limited intervention was put in place that encouraged support to be given to the horses when necessary, bringing the horses into closer contact with humans. This also included closer contact with tourists to Namibia, who frequently see them at the watering area at Garub and near the main road that traverses their grazing grounds. While the horses are credited with bringing tourist dollars to Namibia, there are also concerns about negative horse-human interactions, including vehicle accidents, disruption to sensitive areas by people looking for the horses and disruption of herd dynamics due to becoming too used to or dependent upon humans.