Hyena
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This article is about animal species. For the characters from The Lion King see Shenzi, Banzai and Ed.
Hyenas (or Hyænas) are moderately large terrestrial carnivores native to Africa and the Indian Subcontinent. They are members of the family Hyaenidae.
Physiology
Although hyenas look like rather large 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 is capable of being equivalent to 800 lbs. of pressure and can be used to crush the bones of dead animals.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.
Their front legs are actually longer than their back legs, giving them their unique gait. This unique feature allows them to stalk their prey for many miles at about 6 mph, waiting for their prey to become exhausted from the chase, and then they can move in very quick at speeds of up to 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.
Hyenas are also highly intelligent predators, even more intelligent than the lions (some scientists claim they are of equal intelligence to certain apes) (Said by biologist Jeff Corwin, in an episode of "The Jeff Corwin Experience" concentrating on spotted hyenas). 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 (mentioned in "The Book about Animal Psychology" ("Bogen om Dyrepsykologi"), chapter 4, "Social behaviour" by Danish biologist Hans Lind).
One unique feature of the hyena is that females have a pseudo-penis. Female hyenas give birth, copulate, and urinate through their pseudo-penis. Their pseudo-penis actually stretches to allow for the male penis to enter for copulation, so they have total sexual control over who is allowed to mate with them. The pseudo-penis also stretches during birth. It has been found that one of the things that causes this masculinization of the genitals is androgens that are expressed to the fetus very early on in its development. But one of the interesting things is that when the androgens are held back from the fetus, you stll get masculinization of the genitalia of the females, so scientists still have not figured out what causes the unique development of the pseudo-penis.
Hunting
The spotted hyenas are an example of that the cooperative form of hunting can be chosen by the type of prey, as well as the predator’s ability to hunt and kill the different types of prey. When the hyenas hunt an animal that is bigger than themselves, they act in a dog- or wolf like behaviour; they hunt in packs and together take down the prey by biting into it and dragging it to the ground. If they are after smaller prey, such as a fox, they will hunt alone.
Like dogs, but unlike other animals in the same habitat, hyenas do not kill their prey directly. Having chased their prey 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 disembowlment 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 10-100 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. An adult hyena is capable of taking down a fully grown wildebeest alone, but hunting in packs is proven to be more effective and fast.
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 concentrate on the unfortunate chosen one. Such a hunt can go for a couple of kilometres, with a speed up to 64 km per hour. When the prey is down, the hyenas share the food without any fights worthy to mention. In spite of 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 hunt 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 fast and brave 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 distracts the stallion, until it gives up. A number of 11 hyenas is often required for such a hunt, but the number doubles up when it is feeding time. There is 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 have no illusions about their power, and only hunt the prey they are able to at the specific time (a number of 4 hyenas, for example, wouldn‘t even 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.
Digestion
Hyenas have extremely strong jaws and a very powerful digestion system with highly acidic fluids. This makes them capable of eating and digesting their entire prey - including skin, teeth, horns, hooves and even bones. Their excrement can be either brown or white (white being the result of the digestion of bone material).Life within the Clan
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. Unlike many other animals, female hyenas very rarely mate with highly aggressive males. Instead, they select calm, patient and charming mates. 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.
Hyenas are born with teeth, which means that sometimes when the cubs play-fight they can accidentally kill each other. Hyenas produce such nutritious milk that, unlike lions and wild dogs, they can leave their cubs for about a week without feeding them which allows them to follow the herds of wildebeest, thus ensuring they can obtain the best prey.
Scavenger
Despite common belief, only some species belonging to this family are scavengers, and most of the prey consumed by hyenas was killed by hyenas. The brown and the striped hyena are the only true scavengers, deriving most of their food from others, and the spotted hyena is a true predator, and the most effective predator on the African savannah. The Aardwolf usually eats insects like termites.Classification
Family Hyaenidae- Subfamily Hyaeninae
- *Spotted Hyena Crocuta crocuta (this is the "Laughing Hyena")
- *Brown Hyena Parahyaena brunnea (formerly Hyaena brunnea)
- *Striped Hyena Hyaena hyaena
- Subfamily Protelinae
- * Aardwolf Proteles cristatus
Notes
- G.W.B. Huntingford, The Galla of Ethiopia; The Kingdom of Kafa and Janjero (London: International African Institute, 1955), p. 126.
External links
- [Hyena: Wildlife summary from the African Wildlife Foundation]
- [Robin M. Weare's Hyena pages]
- [Nature-Wildlife]
- [Excerpt about hyenas] from Richard D. Estes's "The Safari Companion" (ISBN 1890132446)
- [Kay E. Holekamp laboratory]
- [Hyena photo and information]
- [A mechanism for virilization of female spotted hyenas in utero]
- [The Hyaenidae Family from Lioncrusher's Domain]
- [The Hyaena Specialist Group]
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