Hyena

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Hyenas
Spotted Hyena
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Hyaenidae
Gray, 1821
Subfamilies and Genera

Hyenas or Hyaenas are moderately large terrestrial carnivores native to Africa and the Indian subcontinent. They are members of the family Hyaenidae. They are known for a chirping, birdlike bark that resembles the sound of hysterical human laughter.

Contents

[edit] Physiology

Although hyenas bear some physical resemblance to wild dogs, they make up a separate biological family which is most closely related to Herpestidae (the family of mongooses and meerkats). The hyena has one of the strongest jaws in the animal kingdom and an adult of the species has only the large cats of the family Felidae (Lions and Tigers) to fear. An adult hyena's bite pressure can reach 50 kilograms per cm² (800 lb per square inch), allowing it to easily crush bone.

Hyenas range in length from 1.2–1.5 meters (3.9–4.9 ft) including the tail, which is 30 cm (12 inches) in length. An adult hyena weighs between 25 and 55 kg (55–120 lb). The pelt can be light to dark-brown on brown hyenas, while the color can be grey, sometimes nearly white on striped hyenas. Aardwolves have a warm, sand-colored coat, while the coats of spotted hyenas can range from dark-brown fur to amber and reddish in color. However, some Hyenas have spots.

Their front legs are longer than their back legs, giving them their distinctive gait. This feature, along with the fact that they have a heart twice the size of an adult lion's, allows them to stalk their prey for many miles at about 10 km/h (6 mph), waiting for it to become exhausted. They can then move in very quickly, at speeds of up to 50 km/h (30 mph).

In ancient times, large hyenas ranged over much of Europe and Asia, but they are much reduced in range and diversity today. Only four species survive: the spotted, brown, and striped hyenas (which together make up the subfamily Hyaeninae), and the aardwolf, which is the only member of the subfamily Protelinae. The Cave Hyena was a prominent predator in much of Eurasia until the end of the last ice age.

Spotted Hyena, Crocuta crocuta.
Spotted Hyena, Crocuta crocuta.

Hyenas are highly intelligent predators, and some scientists claim they are of equal intelligence to certain apes.[1] One indication of hyena intelligence is that they will move their kills closer to each other to protect them from scavengers; another indication is their strategic hunting methods.[2]

One unusual feature of the spotted hyena is that females have an enlarged clitoris called a pseudo-penis. Female hyenas give birth, copulate, and urinate through their protruding genitalia, which stretches to allow the male penis to enter for copulation, and it also stretches during birth. The anatomical position of the genitalia gives females total sexual control over who is allowed to mate with them. Researchers originally thought that one of the things that causes this characteristic of the genitals is androgens that are expressed to the foetus very early on in its development. However, it was discovered that when the androgens are held back from the fetus, the development of the female genitalia was not altered. Other hyena species lack this adaptation, making it a fairly recent one in the hyena line.

[edit] Hunting

Young Spotted Hyenas rest on a road in the Kruger National Park in South Africa.
Young Spotted Hyenas rest on a road in the Kruger National Park in South Africa.
A Spotted Hyena on the run with a jaw salvaged from a nearby carcass.
A Spotted Hyena on the run with a jaw salvaged from a nearby carcass.
Spotted Hyenas feed from a Giraffe carcass amongst a large number of vultures.
Spotted Hyenas feed from a Giraffe carcass amongst a large number of vultures.

The spotted hyenas are an example of how the cooperative form of hunting can be dictated by the type of prey, as well as the predator’s ability to hunt and kill the different types of prey. When hyenas hunt an animal that is bigger than themselves, they may hunt in packs and take down the prey by biting and dragging it to the ground. If they are after smaller prey, they will hunt alone in a fox-like manner. Brown and striped hyena always forage alone, as does the insectivorous aardwolf.

Like dogs, but unlike some other animals in the same habitat, hyenas do not kill their prey directly. Having been chased to exhaustion, their prey is unable to mount any further defence of itself, and is captured and eaten while still alive. Although somewhat distasteful from the human perspective, the speedy disembowelment of the prey means that death often comes sooner than with the methods employed by other predators (for example, suffocation) and is an efficient means of eating which lessens the probability of the kill being lost to another predator.

Hyenas adapt their specific hunting strategy to the environment in which they live. In the Ngorogoro Crater, there is a very rich and concentrated amount of prey, and there are relatively many great beasts such as wildebeest or zebras. These animals are very much bound to one place and don’t migrate. Here, hyenas live in large clans (between 10 and 100 members per clan) and have established hunting territory which they often defend against neighbouring clans. The amount of large prey animals makes cooperative hunting more necessary than in the Serengeti, for example, where the clans often aren’t that large and must follow the herds when they migrate. Hyenas following migrating prey are less territorial, and will often hunt small animals individually as well as large ones in packs. Hunting in packs is proven to be more effective and fast than hunting alone, especially with large prey animals.

It is also common to see that some hyena clans actually have specialized in hunting certain types of prey. One clan may have specialized in hunting wildebeest, whilst another has specialized in hunting zebras. For instance, the “wildebeest hunters” often hunt in small groups (often 2–7 hyenas). When they approach the wildebeest herd, one of them runs into the herd and causes confusion. Then, it picks out a certain animal (usually the oldest, youngest or one that is wounded or weak) it begins to hunt down. The other hyenas then join it, scaring all other wildebeest away and concentrating on the unfortunate chosen one. Such a hunt can go for a couple of kilometres, with a speed up to 64 km/h in short bursts. When the prey is down, the hyenas share the food according to rank and dominance usually without any major fights. In spite of the fact that they are equally hungry, they are tolerant and respect each others’ ranks. The more is usually the better, since the prey can be effectively defended against other predators, such as lions.

The hunting of zebras is slightly different, however, since the social structure of wildebeest and zebra are different. The zebras huddle together when they spot the hyenas, and run away close to each other. A group of hyenas that are after zebras will find this hunt difficult, because the leading stallion fiercely defends his herd with kicks and bites. Again, one single hyena must run up in front and distract the stallion, while another picks out an animal. As soon as this hyena bites, the others will join in, while two hyenas constantly distract the stallion, until it gives up.

An average number of 11 hyenas is often required for such a hunt, but the number doubles up when it is feeding time. There are most often 6 hyenas hunting a wildebeest, but the number on feeding time is the same as with zebras.

The difference in numbers when hunting is connected to how well the prey is able to defend itself. Hyenas only hunt the prey they are able to at the specific time (four hyenas, for example, wouldn‘t try hunting down a zebra). The size and behaviour of the hunting parties is therefore directly connected to the size and behaviour of the prey animals.

[edit] Fighting

Hyenas within the same clan rarely fight in a way that can damage them seriously. Most bickering is settled quickly, even by members that have similar ranking in the social hierarchy. Some loud noises and a couple of light bites is usually enough, and if the fight ever gets out of hand, it is quite normal for a hyena of a higher rank to step in and interrupt the fight. The spotted and brown hyena both live in clans, while the striped hyena and aardwolf rarely socialize outside of immediate family groups. Brown hyena live in smaller and less organized clans, and always give way when faced with groups of spotted hyena or lions.

Even hyenas that are strange to each other would rather avoid battle than recklessly try to kill each other. Usually, scent marking territories avoids conflicts: if a lone hyena should enter a hostile territory anyway, it keeps a low profile and stays out in the borders. Female hyenas are treated with more hostility than males, since males from different clans are needed for breeding in the clan. Strangers are rarely accepted in a clan, but if so, they are usually placed at the bottom of the ranking system.

If a clan member spots an intruder, it will quickly start scent marking, to make the intruder aware of that he is not welcome. Furthermore, the clan member will raise tail and make a whooping noise to warn the rest of the clan. Typically, the intruder will slink away before any physical contact is made.

The situation is different, however, when it comes to two clans fighting each other. The rules are much the same if it is one clan intruding into hostile territory. Hyena clans may try to take over weaker clans' territories, because of lack of prey or peace in their own territory. Human interaction is among the reasons hyena clans do this, because human activities often cause hyena territories to shrink or reduce the available prey population.

When a member of the defending clan spots an enemy clan that has come too close, it calls the whole clan together. Cubs are sent down to their dens and some selected adult females stay and guard them. The other adults, male and female, huddle together with bristling manes and raised tails, making a rumbling "giggle". They form a kind of a wall, to keep the intruders from reaching further into their territory and most importantly, their cubs. The defenders stand their ground and occasionally, one defending hyena rushes out and attacks the enemies. More defenders typically follow, while there are always some hyenas holding their ground, making sure no intruders pass through. The attackers try to push themselves forward as well as possible. If the defenders try to spread them, they typically lunge over the hyena that started the attack to provoke the others and make them unsure.

Fights between clans actually are based on a strict set of rules, and while often portrayed as brutal and reckless, hyena clans will often co-ordinate their attacks. The winning clan is usually the bigger, more numerous one, but not necessarily: If a clan has few members, but those members are extremely bold, they may gain the upper hand.

The rules are slightly different when it comes to two clans on neutral territory. Then it typically is about defending or stealing a kill, but since this isn't as valuable as a territory or young cubs, battles (if there are any) are normally very short and the winner is often the group with most members.

Nevertheless, under normal circumstances, these clan confrontations are rare compared to the many confrontations clans have with lions. When defending territories and dens, the behavior is similar to when the clan is attacked by other hyenas. There is increased attention on the cubs, though, since lions often pay visits to hyena territory to kill their offspring.

Again, the hyenas huddle together to form a wall. It is naturally easier for the lions to break this wall, because of their bulk, but the hyenas quickly form it again as soon as they are spread. If the hyenas are too few, they will not attack the lions, but stay in defense, trying to tire the big cats out.

If the hyenas are numerous enough, however, they lunge forward and aim for the lions' hindquarters and try to rip their haunches and bite their tails off. Since lions have both teeth and claws to fight with, hyenas are more likely to attack from the behind and drag the lion down on the ground, where they attempt to tear the soft belly apart.

If it is the hyenas that are the attackers and are out to kill the lions' offspring, they come in large numbers, distracting most of the adult lions while a couple of quick hyenas snatch the cubs. At least four hyenas are needed to chase off a lioness, while at least six hyenas are required to even up a confrontation with an adult male lion. Again, biting and tearing from behind is preferred rather than facing the big cats' deadly claws.

Similar behavior is seen when stealing a kill, which hyenas are quite successful at. When defending a kill, the hyenas can be the losers when lions are involved, since they don't hunt in extremely large groups but rather prefer to kill several times the same night. The lions often come in large raiding parties to make sure they can steal the hyenas' prey. However, hyenas have learned to deal with this and usually they are fortunate enough to call more of the clan together and take their prey back, unless an adult male lion is present, as male lions seem to truly terrify hyenas and hyenas rarely challenge them.

Stealing kills from cheetahs and leopards and other loners, on the other hand, rarely requires fighting and calling the clan. It can get a bit dramatic when a hyena clan faces a pack of African wild dogs, but not nearly as violent as encounters with lions. Usually, it is the smaller wild dogs that back out. Although smaller species such as the striped and brown hyena are not nearly so formidable as the spotted hyena, they too often find themselves in conflict over food. A group of brown hyena can drive off a solitary spotted hyena or leopard, but quickly back down when faced with more formidable threats. Striped hyena are solitary hunters, but can occasionally drive a leopard or cheetah from a kill. In parts of their range striped hyena come into conflict with wolves over kills, but a pack of wolves will generally drive off a lone hyena.

[edit] Digestion

Hyenas have extremely strong jaws compared to their body size. They also have a very powerful digestive system with highly acidic fluids. This makes them capable of eating and digesting their entire prey, including skin, teeth, horns, bones and even hooves. Since they eat carcasses, their digestive system deals very well with bacteria.

[edit] Life within the clan

Skull of Hyaena eximia.
Skull of Hyaena eximia.
Lower jaw of Hyaena eximia.
Lower jaw of Hyaena eximia.

A group of spotted hyenas (called a "clan") can include 5–90 members and is led by a single alpha female called the matriarch. A complicated social hierarchy governs the clan, which cubs often learn before they begin to walk. Females are the dominant members, followed in rank by cubs, while adult males rank lowest. Male hyenas, which are usually smaller and less aggressive than females, often leave the clan when they are about two years old. Females tend to mate with males from other clans, thereby preventing inbreeding. Female hyenas very rarely mate with highly aggressive males. Instead, calmer and more patient males are selected. Patience is especially important since courtship can last as long as a year. For this reason, dominant and impatient males have difficulty finding mates. Despite the complicated courtship, the female raises her pups without the male. Although it has been seen on occasion, infanticide is not common in spotted hyenas. "Prior to the mother's return, another adult female (a full sister to the new mother) arrived and methodically killed both newborns with crushing bites to the head" (Paula A. White)

Hyenas are born with teeth, which means that sometimes when the cubs fight they can kill each other. BBC's Carnivore! has footage showing the deadly infighting of cubs from the moment they are born. When Paula A. White studied the correlation of cub survival with maternal rank, she found that primary causes of cub death were "intraclan infanticide, disease, orphaning, predation by lions, and a mechanism of filial infanticide" . Hyenas produce milk high in nutrients, so, unlike lions and wild dogs, they can leave their cubs for about a week without feeding them. This allows them to follow the herds of wildebeest, thus ensuring that they can obtain the best prey.

[edit] Scavenger

A Spotted Hyena enters a picnic area to scavange for food in the Kruger National Park in South Africa.
A Spotted Hyena enters a picnic area to scavange for food in the Kruger National Park in South Africa.

Despite common belief, only some species belonging to this family are scavengers, and most of the prey consumed by hyenas is killed by hyenas. The brown and the striped hyena are the only true scavengers, deriving most of their food from others. The spotted hyena is a true predator; one of the more effective predators on the African Savannah.

[edit] In culture and literature

Negative associations have generally stemmed from their tendency to scavenge graves for food (being one of the few creatures naturally suited for this thanks to their ability to devour and digest every part of a corpse, including bone). As such, many associate hyenas with gluttony, uncleanliness, and cowardice.

[edit] In folklore

Hyenas are associated with a number of qualities and stigmas throughout African and Asian folklore.

Their haunting laughter-like calls inspired the idea in local cultures that they could imitate human voices and call its victims by name. Hyenas are also associated with divination and sometimes thought of as tools of demons and witches. In African folklore, witches and sorcerers are thought to ride hyenas, or even turn into them.

The hyena is also (more positively) looked upon as an animal trickster.

Early naturalists thought hyenas were hermaphrodites or commonly practiced homosexuality, largely due to the female spotted hyena's unique urogenital system. According to early writings such as Ovid's Metamorphoses and the Physiologus, the hyena continually changed its sex and nature from male to female and back again. In Paedogogus, Clement of Alexandria noted that the hyena (along with the hare) was "quite obsessed with sexual intercourse." Many Europeans associated the hyena with sexual deformity, prostitution, and deviant sexual behavior.In India, Hyena is also called "Lakarbaggha" in Hindi, the local language.

[edit] In film

Hyenas, especially spotted ones, are hard to train for movies. Their wild instincts are difficult to tame and they are proven to be too intelligent to easily train, refusing to constantly do the same trick out of boredom. They have, however, been used in animated movies many times, as well as having been rendered in live action films via CGI.

Banzai, Shenzi, & Ed.
Banzai, Shenzi, & Ed.

[edit] In television

Skelerena.
Skelerena.
  • A hyena named Nebbich played a prominent role in the first season of the animated series The Legends of Treasure Island.
  • Hyena was the name of a cybernetically enhanced villain on the cartoon Garoyles

[edit] In video games

  • Capcom's first PlayStation 2 Mega Man X entry, Mega Man X7, featured a Maverick boss patterned after a hyena: Flame Hyenard. Like real-life hyenas, Flame Hyenard was identifiable by his loud whooping cries.
  • Players encounter zombified hyenas in the Raccoon City Zoo in the "Wild Things" chapter of Resident Evil Outbreak: File 2.
  • Shenzi, Banzai and Ed play minor villains alongside their hyena brethren in Kingdom Hearts 2.
  • In World of Warcraft you can find Hyenas in the barrens.
  • In the game Space Station: Silicon Valley for the Nintendo 64, you can play as a hyena in the jungle levels.
  • The Pokemon Poochyena and Mightyena both resemble hyenas

[edit] In literature

  • A group of were-hyena characters, led by the hermaphrodictic Narcissus play a role in Anita Blake: Vampire Hunter book Narcissus in Chains.
  • In the book-series "Children of the Earth" by Jean M. Auel the leading character Ayla has an irrational disgust for hyenas, due to previous experiences with them.
  • In Ernest Hemingway's "The Snows of Kilimanjaro," a hyena watches over the dying Harry, and is constantly waking them up during the night.
  • In Yann Martel's "The Life of Pi", the leading character, Piscine, shares a lifeboat with several zoo animals, including a hyena.

[edit] In comics

[edit] In amusement parks

[edit] Classification

[edit] Evolution

Although hyenas bear some physical resemblance to wild dogs, they make up a separate biological family which is most closely related to Herpestidae (the family of mongooses and meerkats). The hyena has one of the strongest jaws in the animal kingdom and an adult of the species has only the large cats of the family Felidae (Lions, Tigers, etc.) to fear. An adult hyena's bite pressure can reach 50 kilograms per cm² (800 lb per square inch), allowing it to easily crush bone.

The hyaenids have no fossil record before the mid-Miocene period, about 15 million years ago. It is believed that the family began in Africa and spread through Europe and Asia. They are thought to have evolved from a member of the viverrids. Extinct hyena genera included civet-like tree dwellers and speedy species designed for running down prey, along with even more powerfully developed bone crushing species similar to modern hyena. Fossil examples include the genera Protictitherium, Ictitherium, Chasmaporthetes, Adcrocuta, Pachycrocuta and Percrocuta (of which P. gigantea was the largest Hyena which ever lived}.

Most lines of hyena died out towards the end of the Miocene, possibly due to competition from early canids. The running hyena Chasmaporthetes survived until the first ice ages, and the Eurasian Cave Hyena survived until the end of the last ice age, when they died out along with much of the Eurasian megafauna.

[edit] Classification

Family Hyaenidae

[edit] Notes

  1. ^ Said by biologist Jeff Corwin, in an episode of "The Jeff Corwin Experience" concentrating on spotted hyenas
  2. ^ "The Book about Animal Psychology" ("Bogen om Dyrepsykologi"), chapter 4, "Social behaviour" by Danish biologist Hans Lind.


[edit] See also

[edit] External links

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