Hyaena hyaena

3. Striped Hyena Hyaena hyaena French: Hyéne rayée / German: Streifenhyane / Spanish: Hiena rayada Taxonomy. Canis hyaena Linnaeus, 1758, India. Of the extant hyaenids, the Striped Hyena is most closely related to the Brown Hyena, and its lifestyle, reproduction, and social behavior more closely resemble those of Brown Hyenas than those of Spotted Hyenas or Aardwolves. Some authorities provisionally recognize five subspecies, distinguished mainly by differences in size and pelage (hyaena from India, barbara from NW Africa, dubbah from NE Africa, sultana from the Arabian Peninsula, and syriaca from Syria, Asia Minor and the Caucasus). However, other authorities argue that current morphological data and other evidence do not support multiple subspecies. Distribution. The Striped Hyena has a very large range, covering much of Africa and western Asia. Although they do not occur in the central Sahara, these animals occur at low density in patches throughout eastern, western and northern Africa, including Algeria, Benin, Burkina Faso, Cameroon, Chad, Djibouti, Egypt, Ethiopia, Ghana, Kenya, Libya, Mali, Nigeria, Mauritania, Morocco, Niger, Senegal, Tanzania, and Tunisia. Striped Hyenas also occur in the Middle East and Central Asia. Middle Eastern and Asian countries included in the modern distribution of the Striped Hyena are Afghanistan, Armenia, Azerbaijan, Georgia, India, Iran, Iraq, Israel, Jordan, Lebanon, Nepal, Oman, Pakistan, Saudi Arabia, Tajikistan, Turkey, Turkmenistan, Uzbekistan, and Yemen. The current distribution of this species is patchy, and usually appears to occur in small, isolated populations. Descriptive notes. The Striped Hyena is the smallest of the three bone-cracking hyaenids, but is substantially larger than the Aardwolf. Head-body 100-115 cm,tail 30-40 cm, shoulder height between 66-75 cm; weight 26-41 kg (males) and 26-34 kg (females). Among the provisional subspecies, body mass and body size are only well studied in syriaca in Israel and dubbah in Kenya. In these populations, there was no significant sexual dimorphism in body size. However, in one recent study in Israel, sexual dimorphism accounted for 39% of the variation in adult body size. Like the other hyaenids, the Striped Hyena has a sloping back because the forelegs are longer than the hindlegs, and has well-developed anal glands used for scent marking. Large ducts from the anal glands open into an anal pouch dorsal to the anus. As in the other bonecracking Hyenas, the head, neck, and shoulders are relatively massive and powerful. The fur is pale gray or straw-colored, with black vertical stripes on the sides of the body. Like the Brown Hyena, the Striped Hyena has longer fur than the Spotted Hyena, giving it a rather shaggy appearance. The Striped Hyena has a black muzzle and a black patch on the throat. It has five to nine vertical stripes on the flanks, two cheek stripes, and clear black transverse and horizontal stripes on all four legs. The head is roundish with a pointed muzzle and long, pointed ears. It has a gray or blond mane that runs along its dorsal midline from the ears to the tail; the mane can be erected to increase the animal’s apparentsize by over 30%. The mane in this species is more pronounced than that in any other hyaenid, with hairs up to 20 cm long. The black and white tail is long and bushy, with hair that is generally coarse and long. Females have two or three pairs of teats, but if they have three, only the caudal two pairs are functional. Juvenile females have well-defined labia-like folds anterior to the vagina. These ridges are hairless and darker and rougher than the surrounding tissue. Juvenile males have smaller, smooth, hairless skin folds along the middle septum close to, but anterior to, the scrotum. Unlike Spotted Hyenas, these genital characteristics are not severe enough to confuse sexing of juveniles, and adult genitalia appear normal. Subspecies descriptions are based on limited data except for syriaca in Israel and dubbah in Kenya. In general animals living in the northern parts of the range tend to be slightly larger than those living in southern regions. Variation in pelage color appearsslight, although the Lebanese population is reported to have a reddish coat color, and hyenas on the Arabian Peninsula are described as having a yellow mark below the eyes and a mixed gray and black dorsal crest. Habitat. In most ofits range the Striped Hyena occurs in rugged, arid habitat or light thorn bush country. These animals drink regularly where wateris available, but they can also survive in many waterless areas. In North Africa they prefer open woodlands and bushy and mountainous regions. The central Arabian and Sahara Deserts are not suitable habitat. In central Asia, Striped Hyenas avoid high altitudes and dense thickets and forests. The maximum elevations recorded are 2250 m in Iran, 2500 m in India and 3300 m in Pakistan. In the Caucasus region, Turkmenistan, Tadzhikistan, and Uzbekistan, prime habitats include savannah and semi-desert regions up to an elevation of 2100 m, mountain areas with strong relief, valleys with abundant caves or other resting sites, and riverine areas. The Striped Hyena avoids areas with minimum temperatures ofless than —15°C to —20°C and more than 80-120 days offrost per year. In Israel, Striped Hyenas are present even close to dense human settlements. In West Africa, they occur in dry scrub savanna and Sahel woodland, particularly in the belt of Acacia raddiana woodland that extends from Senegal to Chad. In eastern Africa, Striped Hyenas are found in a variety of habitats ranging from open savanna to rugged, bush-covered mountain terrain. Food and Feeding. The diet of Striped Hyenas apparently varies considerably from one part of their range to another, but these animals are clearly scavengers with catholic tastes. They are primarily carrion-eaters; their diet consists mainly of dried flesh and bones from carcasses of large vertebrates. They scavenge carrion and the remains of kills made by other predators, including Spotted Hyenas, Cheetahs, Leopards, Lions, and Tigers. The Hyena’s massive cheek teeth and supporting musculature easily permit the gnawing and breaking of bones, as well as the carapaces of tortoises and turtles. Striped Hyenas have also been reported to consume a wide variety of invertebrates, vegetables, fruit, garbage, and small vertebrates that the Hyenas hunt themselves. In central Kenya, analysis of bone fragments and hairs from fecal samples indicated that hyenas regularly consume small mammals and birds that are unlikely to be scavenged. The limited available diet data may underestimate the importance of active hunting in the lives of these animals. In various parts of eastern Africa, Striped Hyenas are reported to supplement their diet with Balanites fruits. The proportion of scavenged and killed prey items in the diet is still a matter of debate as there has been no detailed research on these Hyenas’ food intake. Some authors suggest that only individuals from the three larger subspecies, barbara, syriaca and hyaena, kill large prey, including livestock,as there is no evidence that the smaller subspecies, dubbah and sultana, attack large herbivores. In Turkmenistan the Striped Hyena has been reported feeding on Wild Boar, Kulan, porcupine, and particularly tortoises. In Uzbekhistan and Tadzhikistan, seasonal abundance of oil willow fruits (Eleagnus angustifolia) is reflected in the diet; in the Caucasus region the diet includes abundant grasshoppers. In Israel the Striped Hyena feeds on garbage, carrion, and fruits, particularly dates and melons. In eastern Jordan, the main sources of food are carcasses of feral horses and water buffalo and refuse from localvillages. The Striped Hyena can drink water of very variable quality, from fresh water to soda and salt water, but it may also satisfy its water requirements with melons or otherfruits. Very little is currently known about the hunting behavior of Striped Hyenas, but those few hunts that have been observed involved simple chases and grabs at prey. Seasonal influxes of Striped Hyenas follow migrations of large herds of domestic and wild ungulates in Turkmenistan, suggesting that the Hyenas cover long distances on foraging trips. In Egypt they are known to move along ancient caravan roads where the chance of locating dead camels is high. In Serengeti and in southern Kenya, they spend most of the night actively searching for food or moving between established foraging sites. Striped Hyenas apparently can remember the locations offruiting trees, garbage dumps and other established feeding sites, although the routes taken to re-visit such food sources are seldom repeated on consecutive foraging trips. They are also able to locate tortoises in their hiding places during periods of aestivation and hibernation. Striped Hyenas frequently cache bones or pieces of skin, using their snouts to push these items deep into clumps of grass or stands of dense shrubs. They may also carry food items back to their dens. Bone collections are common at den sites used by Striped Hyenas, although it is often unclear whether these collections represent scavenged or killed prey, and whether the bones collected play a significant nutritional role in the lives of these animals. Several studies have inferred diet by combining data from bone collections and fecal samples. In central Kenya, however, bone collections indicated a much broader range of prey than did scat analysis, and significant portions of bone assemblages were very old bones unlikely to represent material scavenged from fresh kills. From fecal analysis alone, several researchers have found remains of prey items that are more likely to have been scavenged than hunted, and larger mammals are represented far less often in the analysis of hairs in fecal material than would be expected based only on bone collections at dens. Striped Hyenas appear to be strictly solitary foragers, although multiple individuals occasionally gather at rich food sources such as large carcasses or refuse pits. These animals are sometimes found in small groups while resting, but there is no indication that they ever forage cooperatively. Genetic relatedness among members of groups seen feeding together has not been investigated. Foraging activity in Kenya and Tanzania is restricted to hours of darkness except during rain or unusually cloudy weather. Under those circumstances, Striped Hyenas may return to previously visited kills or carcasses, but do not embark on full foraging forays. In many areas, and for many centuries, Striped Hyenas have been described as raiding human graves and carrying away bones. Fruit and vegetable crop raiding by Striped Hyenas is currently considered a serious problem in some parts of Israel. While foraging, Striped Hyenas zigzag across the landscape and do not appear to follow set routes, even when returning to the same food source on multiple nights. Minimum mean distance travelled per night is 19 km at speeds of 2-4 km/h, occasionally trotting at speeds of up to 8 km /h, or running at a maximum of 50 km /h. Overall, the evidence indicates that Striped Hyenas are solitary foragers for which carrion, insects, fruits and vegetable matter represent significant portions of the diet. Activity patterns. The Striped Hyena is almost strictly nocturnal, although it does occasionally engage in some activity after dawn and before dusk. Some authorities suggest Striped Hyenas may be moststrictly nocturnal in areas characterized by relatively intensive anthropogenic activity, and where they are directly persecuted by humans. Movements, Home range and Social organization. In Serengeti, Striped Hyenas travel an average of 19 km per night (range 7-27 km), either following established animal tracks or zig-zagging cross-country. A similar pattern was observed in southern Kenya, where Striped Hyenas followed by human observers covered large distances, but stopped frequently to paste or to investigate grass clumps, carcasses, and other things found on the ground along the way. Home range sizes of one female and one male in the Serengeti were 44 km * and 72 km? respectively. There was little evidence of territorial behavior. Home range size was calculated for a single female in the Negev Desert in Israel to be approximately 61 km?; this range partly overlapped those of two other individuals. In the Laikipia District of Kenya, the mean home rangesize for 12 males was 82 km?, and for eight females was 71 km? with no significant difference in home range sizes between sexes. No evidence ofterritorial defense has been recorded in any studied population, but in some populations these hyenas are known to scent-mark frequently within their home ranges while traveling, and also to defecate in “latrines” near feeding sites and along travel routes. Striped Hyenas are the least well-studied of the extant hyaenids, and their social behavior is very poorly understood. They are most often reported to be solitary. Nevertheless, there appears to be considerable variability with respect to patterns of social grouping among Striped Hyena populations. In some areas, such as central Asia, these animals are reported to form short-term monogamous pair bonds for breeding, with a resulting family unit that may endure for several years. Such family units may sometimes contain offspring from multiple litters. Under these circumstances, both parents and the older offspring may be observed provisioning den-dwelling cubs. Typical group sizes are one or two in all subspecies, but groups of up to seven have been reported in Libya. In Israel, Striped Hyenas are generally solitary, but occasionally several are seen together at a carcass, including both males and females, or females with large cubs. Age-specific foraging data are extremely limited, but cubs have occasionally been observed accompanying their mothers on foraging trips away from the den by 6-12 months of age. Otherwise, foraging is strictly solitary. Almost invariably described as solitary in sub-Saharan Africa, it was recently discovered that Striped Hyenas in the Laikipia District of Kenya are behaviorally solitary but exhibit a polyandrous system of space use. These animals form groups of up to four adults; each group contains one adult female and one to three adult males. Females in both wild and captive populations appear to be highly intolerant of one another, starting around the time they reach puberty. The overall adult sex ratio in the Laikipia population was three males to two females. Members of these groups share a common home range and may be found resting together during daylight hours. The home ranges of group-mates exhibit 85% overlap, whereas their ranges overlap only 22% with those of animals in other groups. Individual group members spend more than 90% of their time alone. Adult male group-mates included both closely-related and distantly related individuals. In contrast to spatial patterns of relatedness documented in other carnivores, pairs in non-adjacent groups tended to be more closely related genetically than pairs living in adjacent groups. This was true for females as well as males. As these animals are usually found alone, very little has been recorded regarding direct social interactions except for captive situations. In this species, males are slightly larger than females, and males also appear to be socially dominant to females in resource competition. The long dorsal hairs of the mane may be erected to enhance the apparentsize of the individual during confrontations with conspecifics. Both mane and tail hairs are erected when the animal assumes a defensive posture, but also when it adopts an aggressive stance. The mane is also commonly bristled whenever the animal pastes. When Striped Hyenas fight they bite at the throat and legs, rather than at the mane. During an agonistic interaction, the subordinate individual may hunch its body, lower its mane, and swing or turn its head from side to side whereas the dominant animal remains bristled and stands erect. The Striped Hyena exhibits a number of visual displays, the moststriking of which is the erection of the mane and bristling ofthe tail like a bottle brush. The mane and tail thus serve as signalling devices during social interactions. When members of the same social group meet after being separated, they engage in “meeting ceremonies”, which involve investigation and licking of the mid-back region and sniffing of the nose and extruded anal pouch. The tail is often held vertically during meeting ceremonies. Meeting ceremonies may also involve repeated pawing of the throat of the greeting partner. The well-developed anal pouch is inverted during scent marking, called pasting, and also during greetings. In scent marking, the anal pouch produces a pungent yellow to beige paste which is deposited at nose-height on grass stalks, stones, tree-trunks, or sticks. Foraging Striped Hyenas pause to paste at frequent intervals, and these scent marks appear to be deposited throughout the home range rather than exclusively at its borders. Pasting has also been observed at large carcasses in the wild, and, in captivity, on food bowls. Some Striped Hyena vocalizations resemble those of Spotted Hyenas, although calls emitted by Striped Hyenas tend to be much softer, and the sounds carry shorter distances. The vocal repertoire of the Spotted Hyenais also far more elaborate than that of the Striped Hyena. Most ofits vocalizations are uttered in the presence of conspecifics. Cubs whine while they are nursing. Giggling or yelling may occur when a Striped Hyena is frightened or being chased by another predator. A long, drawn-out lowing sound sometimes accompanies the defensive posture, and growling may occur during fighting or play-fighting with conspecifics. Breeding. Females are polyestrous and breed throughout the year. Estrus is reported to last one day. No detailed descriptions of sexual behavior in the wild have been reported, but during matings in captivity, females may mate several times at intervals of at least 15 minutes. In the wild, litter size varies from one to four (median of three), after a gestation period of 90-91 days. Average litter size in captivity is 2-4, with a range of one to five. Parturition is preceded by intensive digging behavior by the female. Cubs weigh approximately 700 g at birth; they have adult-like markings but lack manes, and instead have only black spinal stripes. They are born with eyes and ears closed, and they are barely able to crawl, so they are far more altricial than Spotted Hyena cubs at birth. Their eyesfirst open after five to nine days, and cubs may emerge from the den at around two weeks of age. Deciduous teeth start to erupt on day 21. Cubs begin to eat meat at the age of 30 days. In the wild cubs are known to nurse for over one year. They reach reproductive maturity during the second year oflife. The mating system is promiscuous or polyandrous. In the Laikipia population in Kenya, females appear to mate with both group males and males that reside elsewhere. It is not known whether sires contribute in any way to parental care in this population, but lactating females are usually found alone at dens with their cubs, males do not spend significant periods of time at dens, and females appear to be solely responsible for care of young. Multiple paternity in this population occurred in half of sampled litters, and extra-group males sired roughly one third of the cubs born to group females. Striped Hyenas usually use caves, ravines or other sheltered rocky places as dens, although earthen dens may also be used. Den entrances are fairly narrow and may be hidden by large boulders. Two dens were measured in the Karakum Desert. The entrances were 0-67 m and 0-72 m wide. The dens sloped downward 3 m and 2bm and were 4-15 m and 5 m long, with no lateral extensions or special chambers. These simple constructions contrast with much more elaborate dens found in Israel, which can exceed 27 m in length. Status and Conservation. Listed as Near Threatened on The IUCN Red List. Despite their broad distribution, the basic biology of Striped Hyenas, including their abundance in most parts of their range, remains very poorly known. Throughout its range, the Striped Hyena occurs at low densities. There have been only two local estimates of Striped Hyena density in Africa, and it is considered either threatened or data deficient throughout its African range. In Serengeti and Laikipia, density was estimated to be 0-02 per km? and 0-03 adults per km?, respectively. Remarkably little information is available on the species. This is undoubtedly due to its shy, nocturnal, mostly solitary nature, its apparent affinity for rugged terrain, its generally negative reputation, and frequent confusion with, or lack of differentiation from, Spotted Hyenas where the two species overlap. Most adult mortality is directly caused by Lions and humans. Striped Hyenas, particularly those inhabiting areas where natural prey are usually or seasonally sparse, may attack livestock, and as a result they are shot, snared, speared, or poisoned in many parts of their range by ranchers and pastoralists. It appears that the Striped Hyena is already extinct in many localities, and that populations are generally declining. The major reasonsfor this decline appear to be decreasing natural and domestic sources of carrion due to declines in the populations of other large carnivores and their prey, and changes in livestock practices. Moreover, the low densities and associated large home ranges of these animals are likely to increase the chances that populations will become frag