Striped Hyaena

Appearance

It is the smallest of the true hyenas and retains many primitive viverrid characteristics lost in larger species, having a smaller and less specialised skull. Though primarily a scavenger, large specimens have been known to kill their own prey, and attacks on humans have occurred on rare instances. The striped hyena is a monogamous animal, with both males and females assisting one another in raising their cubs. A nocturnal animal, the striped hyena typically only makes itself visible in complete darkness, and is quick to return to its lair before sunrise. Although it is often considered a cowardly animal, it has been known to stand its ground against larger predators such as leopards in disputes over food.

Distribution

The striped hyena's historical range encompasses Africa north of and including the Sahel zone, eastern Africa south into Tanzania, the Arabian Peninsula and the Middle East up to the Mediterranean shores, Turkey, Iraq, the Caucasus, Iran, Turkmenistan, Uzbekistan, Tajikistan, Afghanistan and the Indian Subcontinent. Today the species' distribution is patchy in most ranges, thus indicating that it occurs in many isolated populations, particularly in most of west Africa, most of the Sahara, parts of the Middle East, the Caucasus and central Asia. It does however have a continuous distribution over large areas of Ethiopia, Kenya, and Tanzania. Its modern distribution in Pakistan, Iran and Afghanistan is unknown.

Status

It is listed by the IUCN as near threatened, as the global population is estimated to be under 10,000 mature individuals which continues to experience deliberate and incidental persecution along with a decrease in its prey base such that it may come close to meeting a continuing decline of 10% over the next three generations.

Behavior

The striped hyena is a primarily nocturnal animal, which typically only leaves its den at the onset of total darkness, returning before sunrise. Striped hyenas typically live in groups of 1-2 animals, though groups of up to seven animals are known in Libya.

They are generally not territorial animals, with home ranges of different groups often overlapping each other. Home ranges in the Serengheti have been recorded to be 44 km2 -72 km2, while one in the Negev desert was calculated at 61 km2. When marking their territory, striped hyenas use the paste of their anal pouch to scent mark grass, stalks, stones, tree trunks and other objects.

In aggressive encounters, the black patch near the thoracic and lumbar vertebrae is erected. When fighting, striped hyenas will bite at the throat and legs, but avoid the mane, which serves as a signalling device. When greeting each other, they lick the mid-back region, sniff each others noses, extrude their anal pouch or paw each others throats. The species is not as vocal as the spotted hyena, its vocalisations being limited to a chattering laugh and howling.The striped hyena may dig its own dens, but it also establishes its lairs in caves, rock fissures, erosion channels and burrows formerly occupied by porcupines, wolves, warthogs and aardvarks. Hyena dens can be identified by the presence of bones at their entrances.

The striped hyena hides in caves, niches, pits, dense thickets, reeds and plume grass during the day to shelter from predators, heat or winter cold. The size and elaboration of striped hyena dens varies according to location; dens in the Karakum have entrances 0.67-0.72 m wide and are extended over a distance of 4.15–5 m, with no lateral extensions or special chambers. In contrast, hyena dens in Israel are much more elaborate and large, exceeding 27 m in length.

Reproduction

The striped hyena is monogamous, with the male helping the female to establish a den, raise young and feed her when cubs are born. The mating season varies according to location; in Transcaucasia, hyenas breed in January–February, while those in southeast Turkmenia breed in October–November. In captivity, breeding is non-seasonal. Mating can occur at any time of the day, during which the male grips the skin of the female's neck.

The gestation period lasts 90–91 days. Striped hyena cubs are born with adult markings, closed eyes and small ears. This is in marked contrast to newborn spotted hyena cubs which are born almost fully developed, though with black, unmarked coats. Their eyes open after 7–8 days, and leave their dens after one month. Cubs are weaned at the age of 2 months, and are then fed by both parents. Despite the males' assistance, female hyenas are very protective of their cubs, and will chase their mates away from the cubs if they approach too closely. By autumn, the cubs are half the size of their parents. In the wild, striped hyenas can live for 12 years, while in captivity they have been known to reach 23.

Food

The striped hyena is primarily a scavenger which feeds mainly on ungulate carcasses in different stages of decomposition, fresh bones, cartilages, ligaments and bone marrow. It crushes long bones into fine particles and swallows them, though sometimes entire bones are eaten whole.

The striped hyena is not a fussy eater, though it has an aversion to vulture flesh. It will occasionally attack and kill any defenseless animal it can overcome. It hunts prey by running it down, grabbing its flanks or groin and inflicting mortal wounds by tearing out the viscera.

Predators

The striped hyena competes with the gray wolf in Israel and central Asia. In the latter area, a great portion of the hyena's diet stems from wolf-killed carcasses. The striped hyena is dominant over the wolf on a one to one basis, though wolves in packs can displace single hyenas from carcasses. Both species have been known to share dens on occasion. Red foxes may compete with striped hyenas on large carcasses. Red foxes may give way to hyenas on unopened carcasses, as the latter's stronger jaws can easily tear open flesh which is too tough for foxes. Foxes may harass hyenas, using their smaller size and greater speed to avoid the hyena's attacks. Sometimes, foxes seem to deliberately torment hyenas even when there is no food at stake. Some foxes may mistime their attacks, and are killed.

The species frequently scavenges from the kills of felids such as tigers, leopards, cheetahs and caracals. A caracal can drive a subadult hyena from a carcass. The hyena usually wins in one-to-one disputes over carcasses with leopards, cheetahs and tiger cubs, but is dominated by adult tigers.

Evolution

The species may have evolved from "H. namaquensis" of Pliocene Africa. Striped hyena fossils are common in Africa, with records going back as far as the Middle Pleistocene and even to the Villafranchian. As fossil striped hyenas are absent from the Mediterranean region, it is likely that the species is a relatively late invader to Eurasia, having likely spread outside Africa only after the extinction of spotted hyenas in Asia at the end of the Ice Age. The striped hyena occurred for some time in Europe during the Pleistocene, having been particularly widespread in France and Germany. It also occurred in Montmaurin, Hollabrunn in Austria, the Furninha Cave in Portugal and the Genista Caves in Gibraltar. The European form was similar in appearance to modern populations, but was larger, being comparable in size to the brown hyena.