Hyaenidae Flashcards
Describe the bioecology of hyenas.
What are the four species?
Which is the most commonly encountered? What is unique about its anatomy?
Which species are social? Which are solitary?
What are their typical diets?
BIOECOLOGY (Fowler 8)
- Four species in three genera
- Spotted hyena, aardwolves, striped hyenas, brown hyenas
Spotted hyena most common to encounter in the wild
- Communicate through vocalizations, body posture, scent marking (paste marking)
- Spotted hyenas live in large maternally dominated clans
- Offspring raised by maternal adult
- Genitalia of both sexes is similar
– Female exhibits a peniform clitoris
– Vagina is fused with urethra into a common urogenital tract, terminates in a phallic opening
– Labia are modified to false scrotum with adipose tissue
– Modifications enforce maternal dominance of clan society
- Females are larger
- Scavengers
Brown hyenas
- nocturnal, solitary animals that travel 25-40 km per night in search of food
- Female bonded clans; males maintain genetic diversity
- Clan members participate in communal raising of offspring
- Rarely exhibited, not housed in NA zoos
Aardwolves
- Adapted to a diet of exclusively harvester termites
- Occasionally will consume rodents, carrion, and eggs
- Solitary, nocturnal foragers
- Monogamous; offspring raised by both parents
- Open dry areas with short grass, especially overgrazed farmland
Striped hyenas are the most widely distributed
- Strictly nocturnal, mostly solitary animals
- Communal dens
- Scavengers, but do hunt insects, rodents, birds, larger prey
Describe the anatomy of the hyaenidae.
Describe the relative strength of their forelimbs vs their hindlimbs?
How powerful are their jaws?
How many digits do they have?
ANATOMY (Fowler 8)
* Well-developed forelimbs, shoulders, and neck provide ample power to dismember prey
* Weak hindlimbs sustain long distance loping
* Powerful jaws to crush large bones
* Brown hyena can crush ostrich eggs, spotted hyena cannot
* Dental formula (I) 3/3, (C) 1/1, (P) 4/3, (M) 1/1
o Aardwolf (I) 3/3, (C) 1/1, (P) 3/2-1, (M) 1/1-2
* Four digits on forelimbs and hindlimbs
o Aardwolf 5 on forelimb, 4 on hindlimb
* Highly developed anal glands for scent marking
Describe the husbandry and preventative care of the hyaenidae.
What behavioral aspects of hyaenas need to be maintained in managed care?
How are they fed?
What vaccines should be considered?
What is an important part of their physical examination?
HUSBANDRY (Fowler 8)
* Intelligent, destructive animals
* Nocturnal, secretive nature
* Complex social structure dictates compatible groups
* Commercial meat-based diets supplemented with nutritionally sound dog food and large bones
* Aardwolves: maintained on ground meat, milk, eggs, and supplemental vitamins
PREVENTATIVE CARE
* May be advisable to vaccinate hyenas against canine distemper using a recombinant canarypox vectored or killed vaccine
* Exposure to other diseases has been documented without clinical disease
* Rabies vaccination with a killed product may be advisable in endemic areas
* Be careful to evaluate teeth
Describe the restraint of hyaenas.
What are the preferred injeciton sites?
WHat factors are key to field immobilizaiton of these animals?
What drugs are commonly used?
What complications have been seen in these species?
What is the preferred anticoagulant for samples?
RESTRAINT (Fowler 8)
* chemical restraint in table 51-3
* Injection sites shoulders, forelimbs, and neck when possible
Field immobilization of the brown hyena
* Usually feed one at a time at a large carcass
* Camouflage, low-profile silhouette, and absolute stillness required for success of immobilization
* Infrared lighting can be helpful
* Ketamine/medetomidine, may require supplementation of ketamine
* Blepharospasm, followed by purposeful movement of the head and cervical spine is an indication of impending recovery
West Ch 44 – Hyenidae
Introduction
* Unique Anatomy
o Females are larger and have a hypertrophied, penis-like clitoris through which they urinate, copulate, and give birth
o This makes them useful models to study the mechanisms of sexual differentiation
* Physiology more similar to felines than canines, although they are susceptible to diseases of both
Vascular Access & Sample Collection Sites
* Cephalic vein – extensive branching can make catheterization a little challenging
* Jugular, cephalic, saphenous veins all possible for venipuncture and catheterization
* Clot formation noted with EDTA – heparin noted as preferred anticoagulant
Restraint
* Chemical always recommended in adults – typically by dart
* Cubs less than 1 month can be manually restrained
* Cubs 2-6 months hold can be places in a squeeze cage
Field Techniques - Telazol – 6.5 mg/kg
Captive Hyena Immobilization & Anesthesia
* Ketamine 4-6 mg/kg, xylazine 1 mg/kg, atropine 0.045 mg/kg atropine
* Xylazine does appear to be an emetic – vomiting is common, consider an antiemetic in procedure
* Hind quarters are preferred darting site – excitement produces pronounced side-to-side whipping of the neck and shoulders making them difficult targets
* Eyes are commonly still slightly open (lubricate them) and the bite response is not as readily abolished – so be careful with intubation
Analgesia
* Buprenorphine – 0.01 mg/kg Sc
* Etodolac – 10 mg/kg PO
Complications
* Emesis & salivation from xylazine – atropine reduces secretions
* Hyperthermia – increased activity, possibly exacerbated by ketamine (similar reactions in cats)
* Rarely respiratory depression – reversal of xylazine improves this
* Tonic-clonic-like movements and extensor rigidity with ketamine
Describe the medical management of hyenas in captivity.
What are some important noninfectious causes of disease in these animals?
How are hyenas hand reared?
MEDICAL CONDITIONS (Fowler 8)
* Few infectious disease concerns
Noninfectious diseases
* Intraspecific aggression resulting in traumatically induced wounds are common
* Well known for ingestion of foreign bodies
* zinc toxicosis
o described in captive striped hyena after eating pennies
o severe, nonregenerative anemia, jaundice, and gall bladder edema
o multifocal thrombosis evident microscopically and associated with multifocal necrosis, liver centrilobular hemosiderosis, cholestasis, Kupffer cell hyperplasia, and single-cell necrosis, lymphoplasmacytic, tubulointerstitial nephritis
REPRODUCTION
* Dystocia documented in captive spotted hyena
PEDIATRICS
* Hand rearing can be successful with kitten formulas
* Vx schedules follow that of domestic dogs: 2, 3, and 4 months
What viruses affect hyenas?
Hyena viruses
* Rabies has been documented in wild spotted hyenas
* CDV has been shown in asymptomatic and symptomatic wild spotted hyenas
o Associated with an outbreak in African lions
o Clinical signs: epiphora and nasal discharge, hematochezia, ataxia, lethargy, respiratory distress
* Feline calicivirus, feline herpesvirus, canine parvovirus of feline panleukopenia, feline immunodeficiency virus, and feline corona virus in wild spotted hyenas over 8 years
Pseudorabies
o Aujeszky’s disease virus (ADV), suid herpesvirus 1
o reported in raccoons and hyenas
o differential for rabies
o lesions in raccoons usually not evident
o signs - severe pruritus
o feral swine and European wild boar suspected main
Oral and genital papillomas
o identified in wild spotted hyenas at Masai Mara Game Reserve in Kenya
o spontaneous regression occurrs in some animals
o virus isolated from hyenas most related to lambdapapillomaviruses of cats
Describe the bacterial infections that have been documented in hyenas.
What mycobacterium species has been documented in wild hyenas? What were the clinical signs?
What streptococcal infections have been seen in hyenas? How do these infections present?
M. goodii in a spotted hyena
- bronchial lymphadeomegaly and severe, multifocal and regionally extensive, pneumonia with consolidation
Streptococcus equi subsp. ruminatorum (Lancefield group C) in spotted hyenas
- severe swelling of face, head, and neck; marked mandibular lymphadenomegaly and abscessation with rupture and drainage; respiratory distress; ocular discharge; ataxia; lethargy; and occasionally death
- similar to “strangles” in horses
Describe the parasites that have been reported to affect hyenas.
What coinfections are documented with babesia infection?
What pentostome has been documented affecting hyenas? What were the lesions?
Babesia sp.
o reported in coatis, raccoons, genets, spotted hyena, civets, meerkats
o splenomegaly and anemia
o coinfection with other hemoparasites such as Hepatozoon sp. in hyena and Cytauxzoon sp. in meerkat identified by PCR
Visceral pentastomiaisis
o Armillifer armillatus nymphal migrans
o diagnosed in zoo-housed, brown and striped hyena
o A. armillatus and A. moniliformis reported in aardwolf
o A. moniliformis reported in civets and binturong
o snakes – definitive host
o canids - intermediate host
o encysted nymphs in striped hyena present throughout omentum, mesentery, diaphragm, intestines, liver, spleen, kidneys, and urinary bladder, surrounded by thin fibrous capsule and mild, chronic or neutrophilic (intestinal) inflammation
o diagnosis - identification of characteristic parasites on gross necropsy, histo and PCR with DNA sequencing support gross diagnosis and speciate
A recent study described the hematology and serology of wild brown hyenas.
What seasonal diet changes may affect the biochemistries of brown hyenas?
What viruses were prevalent? How prevalent were they?
Journal of Zoo and Wildlife Medicine 49(4): 931–942, 2018
SERUM BIOCHEMISTRY VALUES AND SELECT SEROLOGIC SCREENING OF BROWN HYENAS (PARAHYAENA BRUNNEA) FROM THE NAMIB DESERT, NAMIBIA
Ingrid Wiesel, Dr. rer. nat., Dipl. Biol., Dawn M. Zimmerman, D.V.M., M.S., and Wm. Kirk Suedmeyer, D.V.M., Dipl. A.C.Z.M.
Abstract: Blood from 30 free-ranging brown hyenas (Parahyaena brunnea) was collected for biochemical analysis and select serologic screening in Namibia from 1997 to 2010. Age was found to have an influence on several biochemical parameters that may be related to growth, a developing immune system, and differences in diet. Seasonal differences in diet of coastal brown hyenas also had an overall significant effect on lipemia values, and differences in stress due to varying capture methods could be associated with an increase in glucose and creatinine kinase. Comparisons among hyena species from published data were inconclusive, as some samples may have been derived from captive populations and individuals. Sera were tested for antibodies against 18 pathogens. Antibodies were not detected for most pathogens, but the proportion of sera containing antibodies against canine adenovirus-1 (CAV-1) and canine adenovirus-2 (CAV-2) was 65% and 84%, respectively. There was no effect of sex, age, year of sampling, or contact with domestic dogs, indicating that CAV-1 or CAV-2 may be enzootic. The prevalence of antibodies to canine distemper virus (CDV) was 43%, and older brown hyenas were 6.9 times more likely to have been exposed to CDV, adjusting for year of sampling and degree of estimated contact with domestic dogs, suggesting epizootic outbreaks. This study is the first to present biochemical reference intervals for wild brown hyenas and provides an indication of disease exposure in this species.
Key Points:
* Brown hyena – restricted to southern Africa, social, live in clans
* Higher ALP, phosphorus, BUN compared to striped & spotted hyenas, higher magnesium than spotted hyenas
* Urban brown hyenas had higher cholesterol than coastal hyenas
* Lipemia more common when coastal hyenas hunt seal pups
* Antibodies to CAV-1 and CAV-2 were detected frequently
o CAV-1 transmitted directly and indirectly through urine CAV-2 direct contact only
* Distemper – older hyenas more likely to be seropositive, likely exposure from past outbreaks from black-backed jackals
Take Home: Adenovirus and canine distemper virus seroprevalence in brown hyenas – some blood values change with location and food availability
