What the hyena's laugh tells: Sex, age, dominance and individual signature in the giggling call of Crocuta crocuta

<p>Abstract</p> <p>Background</p> <p>Among mammals living in social groups, individuals form communication networks where they signal their identity and social status, facilitating social interaction. In spite of its importance for understanding of mammalian societies, the coding of individual-related information in the vocal signals of non-primate mammals has been relatively neglected. The present study focuses on the spotted hyena <it>Crocuta crocuta</it>, a social carnivore known for its complex female-dominated society. We investigate if and how the well-known hyena's laugh, also known as the giggle call, encodes information about the emitter.</p> <p>Results</p> <p>By analyzing acoustic structure in both temporal and frequency domains, we show that the hyena's laugh can encode information about age, individual identity and dominant/subordinate status, providing cues to receivers that could enable assessment of the social position of an emitting individual.</p> <p>Conclusions</p> <p>The range of messages encoded in the hyena's laugh is likely to play a role during social interactions. This call, together with other vocalizations and other sensory channels, should ensure an array of communication signals that support the complex social system of the spotted hyena. Experimental studies are now needed to decipher precisely the communication network of this species.</p

Art in the life of the secondary school pupil

Not Available.Mary K. WeldeleNot ListedNot ListedMaster of ScienceDepartment Not ListedCunningham Memorial library, Terre Haute, Indiana State University.isua-thesis-1933-weldele.pdfMastersTitle from document title page. Document formatted into pages: contains 58p. : ill. Includes appendix and bibliography

Markedly Elevated Antibody Responses in Wild versus Captive Spotted Hyenas Show that Environmental and Ecological Factors Are Important Modulators of Immunity

<div><p>Evolutionary processes have shaped the vertebrate immune system over time, but proximal mechanisms control the onset, duration, and intensity of immune responses. Based on testing of the hygiene hypothesis, it is now well known that microbial exposure is important for proper development and regulation of the immune system. However, few studies have examined the differences between wild animals in their natural environments, in which they are typically exposed to a wide array of potential pathogens, and their conspecifics living in captivity. Wild spotted hyenas (<i>Crocuta crocuta</i>) are regularly exposed to myriad pathogens, but there is little evidence of disease-induced mortality in wild hyena populations, suggesting that immune defenses are robust in this species. Here we assessed differences in immune defenses between wild spotted hyenas that inhabit their natural savanna environment and captive hyenas that inhabit a captive environment where pathogen control programs are implemented. Importantly, the captive population of spotted hyenas was derived directly from the wild population and has been in captivity for less than four generations. Our results show that wild hyenas have significantly higher serum antibody concentrations, including total IgG and IgM, natural antibodies, and autoantibodies than do captive hyenas; there was no difference in the bacterial killing capacity of sera collected from captive and wild hyenas. The striking differences in serum antibody concentrations observed here suggest that complementing traditional immunology studies, with comparative studies of wild animals in their natural environment may help to uncover links between environment and immune function, and facilitate progress towards answering immunological questions associated with the hygiene hypothesis.</p></div

Relative concentrations of total IgG and IgM.

<p>Total IgG (A) and total IgM (B) are significantly higher in wild hyenas (n = 14) than in captive hyenas (n = 15). Females are indicated by open circles and males by filled circles. ***<i>p</i> < 0.001.</p

Bacterial killing capacity (BKC) of serum.

<p>BKC is similar in captive (n = 15) and wild (n = 14) hyenas. Females are indicated by open circles and males by filled circles.</p

Immune defense component model modified from Schmid-Hempel and Ebert [28].

<p>Patterns shown here are hypothesized based on existing literature and the locations within the plot were adjusted based on the results of this study. Bacterial killing capacity (BKC) is the least specific defense and also falls at the constitutive end of the x-axis. Specific IgG falls near the induced end of the x-axis, and is the most specific defense represented here. Anti-nuclear antibodies (ANAs) are specific to nuclear proteins and nucleic acids and can be induced following ligation of endosomal pattern recognition receptors. Natural IgG and IgM are non-specific and can be produced independent of CD4 T cell help. The dashed lines represent primary exposure (left) and secondary (right) exposure.</p

Relative concentrations of anti-KLH natural antibodies.

<p>Anti-KLH natural IgG (A) is significantly higher in wild hyenas (n = 14) than in captive hyenas (n = 11), but there is no difference in anti-KLH natural IgM (B) between wild (n = 14) captive (n = 11) hyenas. Females are indicated by open circles and males by filled circles. *** <i>p</i> < 0.001.</p