Samstag, 11 Februar 2023 11:30

RIEGER, I. (1978)

Social Behaviour of Striped Hyenas at the Zurich Zoo.

Carnivore 1: 49-60.

Abstract:

Meeting striped hyenas sniff at the mane and the anal pouch of a conspecific, which presents by turning its tail upright and extruding its anal pouch. During agonistic behavior, striped hyenas turn their black throat patches towards one another. Bites are directed against this patch and the legs. Back returning inhibits attack. For optical displays, striped hyenas use their tails, manes and ears. Meet i ng behavior of striped and spotted hyenas is compared and the evolution of anal gland phermones is discussed. Results of this paper suggest that certain subspecies of striped hyenas might forage in small social units.

rieger-biblio

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Samstag, 11 Februar 2023 09:48

WIESEL, I. (2006)

Predatory and Foraging Behaviour of Brown Hyenas (Parahyaena brunnea (Thunberg, 1820)) at Cape Fur Seal (Arctocephalus pusillus pusillus Schreber, 1776) Colonies.

Diss. Uni Hamburg. 210 Seiten.

Volltext: https://ediss.sub.uni-hamburg.de/bitstream/ediss/1584/1/IWDissertation.pdf

Conclusions:

The predatory and foraging behaviour of brown hyenas (Parahyaena brunnea) was observed at mainland Cape fur seal (Arctocephalus pusillus pusillus) breeding colonies in the southern Namib Desert. The objectives of this study were to

(1) assess the availability, condition and accessibility of seals for brown hyenas,
(2) evaluate the importance of the coast for brown hyena abundance, movement and energy budget,
(3) determine factors influencing the foraging related time budget of brown hyenas,
(4) assess feeding preferences, and
(5) examine the consumption of prey.

Behavioural observations were conducted at the Van Reenen Bay seal colony and seal pup mortality data was recorded at the Wolf Bay seal colony.
GPS collars were fitted on coastal brown hyenas to determine their movement. Live seal pups were available for brown hyenas all year round, but their increasing size, mobility and activity, as well as the attendance pattern of adult females may influence the brown hyena’s foraging behaviour. Many dead pups were available to scavenge during the pupping season and represented an easy and safe way to obtain food.

In general, predators and prey are mutually influenced by each others behaviours. In Chapter 4 the anti-predator strategies of Cape fur seals towards brown hyenas were reviewed and assessed with regard to their influence on the hyena’s foraging strategies. Although Cape fur seals showed a near complete lack of anti-predator behaviour, the predator-prey system is possibly donor-controlled (Chapter 5) and the usual depensatory effect on prey populations that face novel or exotic predators is not expected (see Sinclair et al. 1998). The numerical response of predators to increased prey numbers as predicted by Holling (1959, 1965) could not be seen in this study (Chapter 5), and seasonality in the availability of seal pups, therefore, may limit brown hyena population growth, and may contribute to the maintenance of large home ranges despite localised food sources. However, coastal brown hyenas’ daily movements were less than that of inland ones, they have a lower field metabolic rate, and hence may consume less food.

Brown hyenas preferred to kill seal pups despite the availability of carrion (Chapter 6). The predation rate was unrelated to carrion availability, but the absolute number of kills was positively correlated to seal pup density. Increasing  seal pup density led to an increase in brown hyena capture rate and hunting efficiency. Furthermore the overabundance of easy and vulnerable prey led to surplus kills. However, brown hyenas foraged opportunistically by scavenging, killing and caching seal pups in proportion to their occurrence at the colony (Chapter 7 and 8), and hence, caused an additional impact on seal pup mortality by not only choosing the doomed surplus. The killing of seal pups seemed to be unrelated to hunger, and surplus killing occurred throughout the study period. Brown hyenas preferred to consume larger and heavier prey, but a large proportion of the brown hyena’s prey was only partially consumed (Chapter 8). Selectivity increased with seal pup density, and feeding and handling times per prey item were reduced. Brown hyenas showed a preference for brain tissue, and the consumption of brain tissue may quickly satisfy the brown hyena’s metabolic requirements, or may be important to keep a positive water balance. Although black-backed jackals (Canis mesomelas) outnumber brown hyenas and are their main competitors at seal colonies, they did not influence the brown hyena’s foraging strategy.

Brown hyenas, therefore, behave opportunistically regarding their feeding preferences and optimally regarding the consumption of seals. Seal pup density influences the brown hyena’s predatory and foraging behaviour, and seasonality in seal availability may limit brown hyena abundance and influence their movement patterns. Future observations of foraging brown hyenas outside the pupping season and at night could yield additional interesting information about adaptations in predatory and foraging behaviour to changes in seal behaviour, abundance and attendance.

wiesel-biblio

WIESEL, I. (2006)

Predatory and Foraging Behaviour of Brown Hyenas (Parahyaena brunnea (Thunberg, 1820)) at Cape Fur Seal (Arctocephalus pusillus pusillus Schreber, 1776) Colonies.

Diss. Uni Hamburg. 210 Seiten.

Volltext: https://ediss.sub.uni-hamburg.de/bitstream/ediss/1584/1/IWDissertation.pdf 

Conclusions

The predatory and foraging behaviour of brown hyenas (Parahyaena brunnea) was observed at mainland Cape fur seal (Arctocephalus pusillus pusillus)

breeding colonies in the southern Namib Desert. The objectives of this study were to

(1) assess the availability, condition and accessibility of seals for brown hyenas,

(2) evaluate the importance of the coast for brown hyena abundance, movement and energy budget,

(3) determine factors influencing the foraging related time budget of brown hyenas,

(4) assess feeding preferences, and

(5) examine the consumption of prey.

Behavioural observations were conducted at the Van Reenen Bay seal colony and seal pup mortality data was recorded at the Wolf Bay seal colony.

GPS collars were fitted on coastal brown hyenas to determine their movement. Live seal pups were available for brown hyenas all year round, but their

increasing size, mobility and activity, as well as the attendance pattern of adult females may influence the brown hyena’s foraging behaviour. Many dead pups

were available to scavenge during the pupping season and represented an easy and safe way to obtain food.

In general, predators and prey are mutually influenced by each others behaviours. In Chapter 4 the anti-predator strategies of Cape fur seals towards

brown hyenas were reviewed and assessed with regard to their influence on the hyena’s foraging strategies. Although Cape fur seals showed a near complete

lack of anti-predator behaviour, the predator-prey system is possibly donor-controlled (Chapter 5) and the usual depensatory effect on prey populations that

face novel or exotic predators is not expected (see Sinclair et al. 1998). The numerical response of predators to increased prey numbers as predicted by

Holling (1959, 1965) could not be seen in this study (Chapter 5), and seasonality in the availability of seal pups, therefore, may limit brown hyena population

growth, and may contribute to the maintenance of large home ranges despite localised food sources. However, coastal brown hyenas’ daily movements were

less than that of inland ones, they have a lower field metabolic rate, and hence may consume less food.

Brown hyenas preferred to kill seal pups despite the availability of carrion (Chapter 6). The predation rate was unrelated to carrion availability, but the

absolute number of kills was positively correlated to seal pup density. Increasing  seal pup density led to an increase in brown hyena capture rate and hunting

efficiency. Furthermore the overabundance of easy and vulnerable prey led to surplus kills.

However, brown hyenas foraged opportunistically by scavenging, killing and caching seal pups in proportion to their occurrence at the colony (Chapter 7

and 8), and hence, caused an additional impact on seal pup mortality by not only choosing the doomed surplus. The killing of seal pups seemed to be unrelated to hunger, and surplus killing occurred throughout the study period. Brown hyenas preferred to consume larger and heavier prey, but a large proportion of the brown hyena’s prey was only partially consumed (Chapter 8). Selectivity increased with seal pup density, and feeding and handling times per prey item were reduced.

Brown hyenas showed a preference for brain tissue, and the consumption of brain tissue may quickly satisfy the brown hyena’s metabolic requirements, or

may be important to keep a positive water balance. Although black-backed jackals (Canis mesomelas) outnumber brown hyenas and are their main competitors at seal colonies, they did not influence the brown hyena’s foraging strategy.

Brown hyenas, therefore, behave opportunistically regarding their feeding preferences and optimally regarding the consumption of seals. Seal pup density

influences the brown hyena’s predatory and foraging behaviour, and seasonality in seal availability may limit brown hyena abundance and influence their

movement patterns. Future observations of foraging brown hyenas outside the pupping season and at night could yield additional interesting information about adaptations in predatory and foraging behaviour to changes in seal behaviour, abundance and attendance.

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Extended and continuous decline in effective population size results in low genomic diversity in the world's rarest hyena species, the brown hyena..

Molecular Biology and Evolution, 35(5): 1225–1237. doi.org/10.1093/molbev/msy037

Abstract:

Hyenas (family Hyaenidae), as the sister group to cats (family Felidae), represent a deeply diverging branch within the cat-like carnivores (Feliformia). With an estimated population size of <10,000 individuals worldwide, the brown hyena (Parahyaena brunnea) represents the rarest of the four extant hyena species and has been listed as Near Threatened by the IUCN. Here, we report a high-coverage genome from a captive bred brown hyena and both mitochondrial and low-coverage nuclear genomes of 14 wild-caught brown hyena individuals from across southern Africa. We find that brown hyena harbor extremely low genetic diversity on both the mitochondrial and nuclear level, most likely resulting from a continuous and ongoing decline in effective population size that started ∼1 Ma and dramatically accelerated towards the end of the Pleistocene. Despite the strikingly low genetic diversity, we find no evidence of inbreeding within the captive bred individual and reveal phylogeographic structure, suggesting the existence of several potential subpopulations within the species.

westbury-biblio

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Donnerstag, 14 Juni 2018 13:24

RUCH, P. (2000)

Auswertungen der Sektionsbefunde an Hyänen aus vierzehn deutschen, österreichischen, schweizerischen und niederländischen Zoologischen Gärten sowie Untersuchungen zum Umgang mit Hyänen.

Results of the pathological examination from hyenas in zoos in Germany, Switzerland, Austria and the Netherlands and a analysis to the handling of hyenas.

Dr. med. vet. Dissertation

153 Seiten

Fachbereich Veterinärmedizin der Freien Universität Berlin
14 Zoos in Deutschland, Österreich, der Schweiz und den Niederlanden

Abstract:

In the introduction some zoological facts about the two species of hyenas are given. Contributions concerning nutrition, handling and zoological management of hyenas, immobilisation, blood parameters and vaccination are following. The main part of this dissertation deals with diseases of hyenas in the literature available and compares these findings with those of captured animals. For this purpose zoological gardens in Switzerland, Austria, The Netherlands and Germany were asked for support. As hyenas are not visitors favourite animals in zoos, it is surprising to find more than two hundred sources of literature and reports of fourteen zoological gardens with 97 results to evaluate. Considering the results of this study, it is noticable that infectious diseases are rarely diagnosed. Of other diseases losses of cubs around the time of birth are main problems. Diseases of the reproductive tract, respiratory tract, traumas, neoplasms, the circulary system, the digestitive tract, the urinary tract, endocrinological and central organs occur in different frequencies. For the first time results from the circulary system, the kidney, the respiratory system and the male genitaltract are listend. It is neccessary to examinate all deed hyenas to find out more about their wellness and sickness in future.

 

ruch-biblio

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