Equus zebra
mountain zebra

There are two distinct subspecies of mountain zebras (Equus zebra): Cape mountain zebras, E. z. zebra, and Hartmann's mountain zebras, E. z. hartmannae. Cape mountain zebras are found only in South Africa. Natural populations are found in the Mountain Zebra National Park (MZNP), Gamka Mountain Reserve, and in the Kamanassie Mountains. Populations of Cape mountain zebras have also been established in Karoo National Park, Karoo Nature Reserve, Commando Drift Nature Reserve, De Hoop Nature Reserve, and Tsolwana Game Ranch. Hartmann’s mountain zebras range from South West Africa into extreme southwest Angola. Their distribution is highly discontinuous. (Klingel, 1990; Lloyd, 1984; Nowak, 1999; Penzhorn, 1988)

Mountain zebras inhabit slopes and plateaus in mountainous areas of South Africa and Namibia (South West Africa). Cape mountain zebras may occur up to 2,000 meters above sea level, but move to lower elevations in the winter. The habitat in South Africa provides regular precipitation and a fairly constant food-supply year round. Hartmann’s mountain zebras differ from Cape mountain zebras in that they occupy an arid region in a mountainous transition zone on the edge of the Namib Desert. Surface water is patchy in this area and as a result, E. z. hartmannae must wander between the mountains and sand flats in order to find patches of grass. (Klingel, 1990; Nowak, 1999; Penzhorn, 1988)

Equus zebra is a fairly large-sized, striped member of the horse family. Adult mountain zebras have a head and body length of 210 to 260 cm, and a tail length of 40 to 55 cm. Shoulder height ranges from 116 to 150 cm. Mountain zebras typically weigh between 240 and 372 kg. Adult Cape mountain zebra mares average 234 kg and stallions usually weigh 250 to 260 kg. Adult Hartmann's mountain zebrasare slightly larger, with mares averaging 276 kg, and stallions averaging 298 kg. Stallions 7 years and older have a mean weight of 343 kg, and a mean shoulder height of 144.5 cm.

The ground color on the body is white, with black to deep brown stripes which continue through the short, erect mane. The stripes on the head and body are narrow and more numerous than those on the rump, and the legs are striped to the hooves. The posterior portion of the dorsal stripe forms a distinctive “gridiron” pattern that continues onto the tail and extends to the whisk near the tip. The muzzle is black.

Both subspecies of E. zebra are good climbers and have exceptionally hard and pointed hooves compared to other equines. The most distinguishing characteristic is the presence of a dewlap, or fold of skin, hanging from the throat.

The color pattern of E. zebra is intermediate between Burchell’s zebra and Grevy’s zebra. Equus zebra can be distinguished from E. burchelli by having a dewlap; narrower and more numerous stripes on the head and body; broader stripes on the hindquarters with no “shadow” stripes; a “gridiron” pattern on the rump; white under-parts with a mid-ventral black stripe on the chest and belly; and ears that are more than 200 mm long. (Joubert, 1974c; Klingel, 1990; Nowak, 1999; Penzhorn, 1988)

Cape mountain zebras are slightly smaller than Hartmann’s mountain zebras. The upper 2 to 3 dark stripes on the rump are very broad, whereas they are less so in Hartmann’s mountain zebras, where some of the white stripes may be more broad than the dark stripes. (Klingel, 1990; Nowak, 1999; Penzhorn, 1988)

The life span of mountain zebras in the wild is usually 20 or more years. The oldest documented mountain zebra in captivity is an E. z. hartmannae that was 29 years and 6 months. (Klingel, 1990; Nowak, 1999)

Equus zebra is a social species with populations consisting of breeding herds and bachelor groups. Mountain zebras are non-territorial but breeding herds occupy home ranges with extensive overlap. When a breeding herd separates, the home ranges of the resulting herds include the home range of the original herd, but are larger. Penzhorn (1982a) found that this illustrates the role of mares in delimiting group activities, and therefore, in defining the home range of a breeding herd.

There are social hierarchies within a breeding herd. The stallion is the dominant member of the herd, with an evident linear hierarchy existing among mares of small herds. In newly established herds, the stallion must actively prevent mares and foals from leaving. In larger, often longer-established herds, the stallion's role is relatively passive, and social hierarchies are harder to determine because each herd member appears to know its relative position. Although dominant mares are more likely to initiate most herd activities, there is no straightforward correlation between dominance and leadership.

In Cape mountain zebras, estrus and the birth of a foal can influence the social hierarchy by causing mares to temporarily rise in standing. However, Penzhorn (1984) found that reproductive success is not essential for social dominance. A foal's hierarchical position is more or less determined by its size, but foals also receive some benefits from the status of the mother when she is nearby.

Bachelor groups also have a rank hierarchy, but it is less stable than that of breeding herds. (Joubert, 1972a; Klingel, 1990; Nowak, 1999; Penzhorn, 1982a; Penzhorn, 1984; Penzhorn, 1988)

Both subspecies of mountain zebra are predominately diurnal, and are active in the early morning and late afternoon to sunset. Grazing and resting occupy most of the daylight hours. Resting is done either standing up or lying down. Mountain zebras usually drink once or twice per day. During cold weather, they often look for shelter in wooded ravines and shallow caves, and visit east-facing slopes on cold mornings to sun themselves.

Breeding herds of E. z. zebra show seasonal differences in their selection of certain vegetational communities. Selection may not be just for food, but also for shelter, drinking spots, and mineral licks. Rainfall pattern also affects the distribution of mountain zebras. (Joubert, 1972b; Klingel, 1990; Nowak, 1999; Penzhorn, 1982b; Penzhorn, 1984)

Individual grooming takes the form of shaking, rubbing, scratching, nibbling, and localized muscle contractions. Individuals also usually take a dust bath daily. Mountain zebras participate in mutual grooming, which not only has a practical function, but is also important in maintaining group cohesion. Mutual grooming takes place most often between mares and foals. However, it also occurs between foals and herd stallions, mares and herd stallions, and between pairs of mares. (Joubert, 1972b; Penzhorn, 1984; Penzhorn, 1988)

Although play has rarely been recorded in E. z. zebra, it is more common in E. z. hartmannae. Play patterns include racing and chasing, challenge games, and play-fighting. Challenge games usually consist of nasonasal contact followed by mutual grooming or body rubbing. (Joubert, 1972a; Penzhorn, 1984; Penzhorn, 1988)

Home Range

In the winter, breeding herds have a grazing area of 6 to 20 km2 with summer grazing areas being considerably smaller. Herds of E. z. hartmannae may cover more than a couple of thousand square miles annually searching for forage. In MZNP, the home range of E. z. zebra averages 9.4 km2 and ranges from 3.1 to 16 km2. (Klingel, 1990; Penzhorn, 1982a; Penzhorn, 1988)

Mountain zebras communicate using mainly visual and auditory cues. Because no two individuals have identical stripe patterns, body pattern can be used for individual indentification. At close range, individuals can also be recognized by smell.

Among all members of the horse family, the positioning of the ears, the stretching of the corners of the mouth, the exposure of the teeth, the opening of the mouth, and the positioning of the head and tail serve as signals of an individuals’ mood or intentions. Ears laid flat back against the head signal threat, especially when accompanied by a lowered head and open mouth. During greeting rituals, mountain zebras touch noses and communicate rank by the positioning of the ears. As a gesture of inferiority, younger individuals hold their ears to the side and make chewing motions with exposed incisors when greeting adults. (Klingel, 1990; Penzhorn, 1988)

Mountain zebras make a variety of vocalizations. Stallions make a high-pitched alarm call or snort to alert herd members to danger. Bachelor stallions make a drawn-out squeal when confronted by a herd stallion. In order to express contentment when feeding, mountain zebras make a soft sound caused by forcing air between closed lips. (Joubert, 1972a; Penzhorn, 1984; Penzhorn, 1988)

Both subspecies of mountain zebra are herbivorous. The primary diet consists of grass but also includes browse. In MZNP, E. z. zebra directs its selection at greener plant species with a high leaf:stalk ratio. Even so, they are still coarse grazers and will exploit both stem and leaf parts of chosen grasses. Grobler (1983) found that they feed on only 26% of the available plants, and only 7 of 17 grass species present at feeding sites. The primary grass eaten is Themeda triandra. Other grasses consumed include: Cymbopogon plurinodis, Heteropogon contortus, Setaria neglecta, and Enneapogon scoparius. Cape mountain zebras of all ages also frequent mineral licks, especially during the summer. (Grobler, 1983; Nowak, 1999; Penzhorn, 1982b; Penzhorn, 1988)

The dominant stallion alerts other herd members to danger with a high-pitched alarm call or snort. He then takes up a defensive position to the rear of the herd while a mare, usually the one with the youngest foal, leads the rest of the herd away. Flight is the most common response to threat, and is sometimes accompanied by a defensive kick. Pulling the ears flat back against the head, lashing the tail, and lowering the head with the neck outstretched and teeth bared, is the form taken for threat behavior. Although fighting is rarely seen, it consists of biting at the opponent's head, neck, legs, and hindquarters. Mountain zebras act in response to the flight and or alarm signals of black wildebeest (Connochaetes gnou). However, they rarely respond to similar signals of smaller antelope species. (Joubert, 1974a; Klingel, 1990; Nowak, 1999; Penzhorn, 1984; Penzhorn, 1988)

Especially at high temperatures, the striped pattern of E. zebra may serve as camouflage, as an adaptation to to the resultant "waviness" of the air (Klingel, 1990). At a distance of a few hundred yards, the stripes make a mountain zebra appear indistinct. To some degree, stripes may also provide protection against blood-sucking insects that transmit disease such as bot-flies and ticks. (Klingel, 1990)

In addition to serving as prey for certain mammalian carnivores, mountain zebras also serve as hosts for a variety of tick, bot-fly, nematode, and cestode species. They also associate with several species of birds that presumably remove external parasites from them. As grazers, mountain zebras may also aid in seed dispersal, and the creation of habitat for smaller animals including mesopredators. (Joubert, 1972a; Penzhorn, 1988)

Historically, E. z. zebra was hunted for its hide, and because the species competed with livestock for grazing, interfered with agricultural interests, and allegedly broke fences. (Nowak, 1999; Penzhorn, 1988)

Mountain zebras bring in money from ecotourism, and some are still harvested for their skins. (Nowak, 1999; Penzhorn, 1988)

The IUCN Red List indicates that the entire species E. zebra is vulnerable (1994). The IUCN, and U.S. federal list both indicate E. z. zebra as endangered. It is also listed as endangered by CITES and is placed on Appendix I. Equus zebra hartmannae is listed as threatened by the IUCN, U.S. federal list, and is listed on Appendix II by CITES.

The major threats to E. zebra include habitat loss and degradation, invasive alien species, harvesting, persecution, and intrinsic factors such as a restricted range. Mountain Zebra National Park and other reserves were established for the protection of E. Z. zebra. As of 1995, they were estimated at over 700 individuals. During the 1950s, numbers of E. z. hartmannae were estimated at 50,000 to 75,000 individuals. In 1992 they were estimated at only about 8,000. (Nowak, 1999; Penzhorn, 1988)