Hyena

By Joe

Taxonomy

Kingdom - Animalia
Phylum - Chordata
Class - Mammalia
Family - Hyenidae
Order - Carnivora
Genus - Crocuta, Proteles, Parahyaena, Hyaena
Species - Hyena

Evolution

Hyena Subspecies: Spotted Hyena, Striped Hyena, Brown Hyena and the Aardwolf
Hyenas have been in existence for 22 million years
Closing living relative to this species are Mongooses and civets
3 ancestors of this species include: The Giant short-faced hyena, Adcrocuta and Protictitherium (a genus of hyena with retractable claws and are the earliest known to have existed).

DESCRIPTION

Brown Hyena

Physical Appearance

Hyenas have long strong necks and snout, power jaws and resemble a lanky dog with a short tail, they have an arched back with broad shoulders, pointed ears and sharp teeth.

Striped Hyena

Point Characteristics

Hyena's are known for all of their vocalizations in the wild

They're actually more related to cats than they are to dogs despite their canine appearance

Hyenas are great mothers

They are scavengers but will occasionally hunt their own food

They live in packs called clans that can have up to 130 members

Spotted Hyena

Sizes of Hyenas

The most common of all Hyenas, the spotted hyena can grow up to 4 to 5 feet long while their Brown and Striped relatives range from 2 to 3 feet. The smallest of the Hyena family is the Aardwolf.

Weight of Hyenas

The heaviest spotted hyenas can weigh up to 140 pounds, average around 100 to 120. Striped Hyenas range from 49 to 120 pounds, the smallest of all being aardwolves which are around 17 pounds.

Aardwolf

Life Span

The hyena family across its four species lives from 10 to 12 years in the wild

Differences between Males and Females

Funny enough, female hyenas, which are dominant, have a male-like reproductive organ which allows them to deliver babies. Female hyenas are larger and males have stomachs that curve upward. As Hyenas get older, it becomes increasingly difficult to tell males and females apart.

Description of Habitat

How much rainfall do hyenas get?

The savannah's of Africa have a wet/dry climate and during the dry season, there are only 10 to 30 inches of rainfall. The area has seasonal rainfall however which dominates three to five months of the year.

What is the terrain like?

The terrain in Africa's savannah is constant humid temperatures, humidity consistently remains above 70% in the dry season. In the savannah there are dispersed trees, tropic plants like acacias, whistling thorns and Bermuda grass. Watering holes, rivers, rock formations and wide sweeping grass lands are common terrain in Northern Africa. The other animals that frequent this area are wildebeest, zebra, lions, baboons, leopards, elephants, birds of various sizes, warthogs, wild dogs and the hundreds of other species native to the diverse ecosystem of north Africa.

Distribution

What continents are Hyenas found on?

Hyenas are mainly found in North and Northeast Africa as well as eastward into the middle east and India. Only found on two continents excluding captivity

Are Hyenas found on invasive at all?

Hyenas are not invasive at all lmao

Diet

What exactly do hyenas eat and how do they get it?

Hyenas are scavengers so a primary source of food are the carcasses of zebra and wildebeest from larger predators like lions or leopards. Although, hyenas are still skilled predators and can hunt wildebeest, zebra, warthogs, unprotected lion cubs and antelope in packs. They also eat birds, lizards and snakes.

The Aardwolf subspecies is an insectivore and it eats termites. They can eat 30,000 of them in one night thanks to their flat tongues

How often do hyenas eat?

Hyenas can eat up to 32 pounds of meat per meal, they only need to eat about every 12 days

Special Foods Hyenas eat:

Hyenas have been known to eat young lions and hippopotamus as well as eat anything from elephants to termites.

Social Structure

Hyenas live in clans with typically 100 or so members, to the left is an example of a Hyena hierarchy, they're very social creatures.

The roles in the hyena clan are female dominant, this is theorized to be the result of hyena females just generally being more aggressive than males. It also has to do with the fact that when hyena males hit puberty, they venture out and find new clans for females to mate with. Joining a new clan automatically makes them rank lowest on the social ladder. Males have a lower aggression level because there is no possibility they can fight over mates. Because of the female hyena's "pseudopenis" it is impossible for a male to mate with a female who doesn't want to. Mating is entirely female controlled.

Hyenas also have hierarchal dynamics where offspring born from hyenas will generally sit a place below their mothers on the social ladder.

These social dynamics are most important when hunting, hyenas spend most of their time in small groups or alone but when they come together for hunts with up to 35 members, high-ranking females and their offspring have first dibs.

Reproduction

Well, to start, female hyenas have a "pseudopenis" which is near identical to a male's sex organ which they use to give birth through as well as mate with.

Here is the mentally scarring description of a hyena mating ritual from Gender Inclusive Biology:

A female spotted hyena mates and gives birth through her penile canal. When mating, a female retracts the "pseudopenis" on itself, 'much like pushing up a shirt sleeve,' and creates an opening into which the male inserts his own penis. The female's "pseudopenis" is located in the same spot as the male's penis, higher on the belly than the vagina in most mammals.

(EN25) L. Frank and S. Glickman, 1994, Giving birth through a penile clitoris: Parturition and dystocia in the spotted hyena (Crocuta crocuta), J. Zoology London 206:525-31; L. Frank, M. Weldele, and S. Glickman, 1995, Masculinization costs in hyenas, Nature 377:584-85. )

Reproduction Cont.

Hyenas mate on average for twice a year and have on average two pups per litter. Their first birth causes 15% of females to die during childbirth along with 60% of firstborn pups, it begs the question why they would need this "pseudopenis," it seems a bit impratical.

Their breeding takes place during Africa's dry season, May to August.

Members of both sexes with mate with several partners over the course of several years.

Development

Here is a detailed development cycle for spotted hyenas from the San Diego Zoo's Fact sheet:

Vocal and mobile within 10 days of birth (Kruuk 1972)

Hair gradually turns to spotted coat (as in adults), c.1.5-2 months of age (Kruuk 1972)

White rings develop around the eyes at 6 weeks of age (East and Hofer 2013; Pournelle 1965)

Lighter hair spreading across the face to the neck, shoulders and rest of body (East and Hofer 2013; Pournelle 1965)

Legs are the last to retain dark pigment (Kruuk 1972)

Participate in greeting "ceremonies" by 1 month of age (Kruuk 1972)

Weaned at c.1 year of age; twins typically nursed for longer periods (Holekamp et al. 1996; Mills 1984b)

12-15 months in southern Kalahari clans (Mills 1984b)

6.7-18.8 months based on results of a 7 year study of a large clan living in Masai Mara National Reserve, in southwest Kenya (Holekamp et al. 1996)

As hyenas grow, they are raised in clans with practically zero differentiating factors between male and females. Males leave at around 24 months (When both sexes hit sexual maturity) and 1 to 38 months later, find new clans to find females to mate with.

Causes of Death

Predation - Largest predator to hyenas are lions, they don't actively hunt hyenas but both animals hunt the same prey and hyenas will often bully lions into giving up their recent kills. Because of their scavenger nature, hyenas will often die by the predators they steal from including the aforementioned lions as well as african wild dogs and leopards.
Sexual Competition - Not known to kill over mates
Disease - Disease isn't actually a major threat to hyenas, they have been documented to survive anthrax and rabies infections, and outbreaks of several other viral diseases that decimated populations of other carnivores. High ranking hyenas have been known to have higher levels of basic immune defenses
Other causes of hyenas include human conflict, hyenas will kill livestock and will be hunted as a result. Spotted hyenas are also hunted for sport and for medicinal purposes

Competition

Interspecies Competition - Males and females will do anything to promote their offspring which includes killing each others offspring
Intra-species Competition - The main competition for hyenas are lions, hyenas can survive off of other animal's kills just because of their strength in numbers and powerful jaws but stealing other animal's dinner almost never goes smoothly. In short, in large numbers, hyenas can bring down a lion with easy but one on one, a lion will almost certainly kill a lone hyena. The two predators are very territorial and if either animal wanders into the other's territory, they will be swiftly killed.
It's also worth noting that hyenas have a pretty important rivalry with African wild dogs. Wild dogs aren't scavengers but do bring down prey in packs so they frequently clash but one on one, a wild dog stands no chance against a spotted hyena.
Affect of invasive species - No major invasive species affect hyenas

IUCN Rating

Hyenas are labeled as "Least Concern" by the IUCN Red List. However, their populations are decreasing outside protected areas due to hunting, trapping and deforestation.

Population:

Spotted Hyena - Decreasing, least concern

Between 27,000 to 47,000

Brown Hyena - Stable, near threatened

Between 5,000 to 8,000

Striped Hyena - Decreasing, near threatened

Between 4,000 to 14,000

Aardwolf - Stable, least concern

Widespread, uncommon in range

Impact of Humans

Hyenas are often seen as a pest to farmers and people who have to live near them, because of this, they are poisoned, killed or trapped if they come into contact with humans not on protected reserves. Humans also can hunt hyenas for sport which effects there numbers no more than hunting any other animal would.

From Scientific American:

> “Humans are consistently indicated as the major source of mortality…largely because the [hyena] is loathed as a grave robber, and because of incidents of damage to agriculture…and livestock,” reports the IUCN. Also taking a toll is illegal hunting for striped hyena skins and body parts for use in traditional medicine.

> Meanwhile, only 5,000 to 8,000 Brown hyenas today roam parts of sub-Saharan Africa. The brown hyena is relatively safe in protected areas, but clashes with humans elsewhere have taken their toll

Spotted Hyenas do not need to worry about human conflicts as much thanks to their ability to adapt to humans around them, their brown and striped relatives could face severe endangerment in the future due to their clashes with humans. Humans have been interacting with different species of hyenas for hundreds of thousands of year, our ancient ancestors 117,000 years ago ate on the scavengers for food.

Organizations like 'Brown hyena research project' and 'Botswana predator conservation trust' aim to protect a better future for hyenas in Africa.

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