Bioacoustics of Proteles cristata

Movements, Home range and Social organization. A social unit, which occupies a welldefined territory throughout the year, consists of a male-female pair and their most recent offspring. All natal animals disperse from the territory, usually 1-2 months before birth of the nextlitter. Pair bonds arefairly stable lasting 2-5 years. Males without mates (due to death or abandonment by females) establish pair bonds with adjacent females and may abandon their originalterritories. Territory size ranges from 1-5 km? in East Africa to 3-8 km? in South Africa , and appears to be negatively related to the density of available termite mounds. Territories in the Northern Cape Province of South Africa generally supported 3000 termite mounds with an average of 55,000 termites/mound. Aardwolf density reaches 1 adult /km? in optimal habitat. Territories are maintained primarily by scent marking, which is concentrated along territory boundaries, but direct interactions between neighboring residents also occasionally occur. Both males and females actively defend territorial boundaries. Chasing and fighting, with manes raised, occurs between same-sex individuals defending territories. Intruders encountered within the territory are usually chased to the boundary and mutual avoidance is generally practiced along boundary areas. If physical contact occurs both combatants drop to their carpals and bite at each others’ necks. Although territorial behavior is exhibited by males and females,it differs between mating (June andJuly in South Africa ) and non-mating seasons. Direct fights between Aardwolves appear restricted to the mating season. Whereas females tend to stay within territory boundaries year round, male behavior undergoes a marked change at the start of the mating season. After an approximately one-month “scouting” period at the beginning of the mating season, when males make frequent extra-territorial movements, yet largely refrain from pasting outside the territory, they begin more aggressive extra-territorial pasting. Their movements outside the territory continue to increase, peaking in frequency about a week before females come into estrus. These excursions are suggested to be advertizements of quality to both males and females in surrounding territories. Males engage in consecutive over-markings by pasting on particular grass stalks; the less aggressive, and apparently less fit, individual will eventually cease pasting, thus “losing” the contest. During pre-estrus females also increase their rate of pasting, primarily along territory boundaries and just outside them, apparently to encourage visits by extra-pair males. Visiting males during this period frequently “flirt” with resident females and chase or fight males that they encounter. “Flirting” typically involves the male running toward the female, then veering off and prancing past with his tail raised. However, by the time the female is in estrus (lasting 1-3 days) she is typically left with only her resident male, and potentially an aggressive neighbor. As in Striped Hyenas, there have been cases in which two male Aardwolves shared a territory with a female, both males mating with her and both guarding her cubs, but this appears to be exceptional and rare. Aardwolves are remarkably antisocial outside the breeding season. Members of resident mixed-sex pairs feed alone and typically ignore each other when they meet. Unlike the other three hyaenids, Aardwolves usually do not engage in greeting ceremonies between familiar individuals, with the exception of an occasional muzzle to muzzle sniff between mother and cub. In South Africa , nightly distance traveled by foraging females ranged from 1-5 to 9-1 km (average 4-2 km). Summer travel distances ranged from 8-12 km per night, whereas winter distances were highly variable (from less than 3 km to more than 24 km ) depending on whether males were conducting extra-territorial mating forays. Travel speed is 2-3 km/h when not feeding, and about I km/h when feeding intensely. Aardwolves return to underground burrows during the day. There are typically 5-6 dens per territory. Dens are used for only 1-2 months at a time, and mates rarely use the same dens concurrently. Because Aardwolves rarely interact, the primary form of communication is olfactory. Like the other three hyaenids, the Aardwolf engages in scent marking behavior called pasting, during which a strong-smelling, yellowish-orange secretion (which quickly turns black) is deposited onto grass stalks from an extruded anal gland, located just above the anus. In addition to marking frequently at dens and latrines, which generally are not associated with territory boundaries, Aardwolves appear to use pasting as a means of territory defense. Boundary marking occurs most frequently, and is most concentrated along borders where neighboring Aardwolves maintain territories. Pasting is generally frequent, occurring about twice every 100 m of travel, and about 200 times per night, with males pasting more than females. Based on experiments with translocated scent marks, information conveyed in scent marks appears to include the sex, female reproductive state, and individual identity, at least in the case of resident neighbors, partners, and self-recognition. Outside the mating season, pasting outside territory boundaries is rare if not nonexistent, but this behavior, particularly by males, changes notably during mating periods. Even though direct interactions are rare, Aardwolves possess an impressive visual display, during which the hairs along the mane are erected, resulting in a near doubling of the apparent size of the animal. This is used in intraspecific aggressive interactions involving territory defense and in interspecific defensive interactions. Although generally a silent species, the most comprehensive analysis of the vocal repertoire of Proteles identified nine distinct sound types : “purr”, whine, jaw click, lip smack, growl, snarl, bark, squeal, and a whizzing sound which was only documented in one individual. Agonistic vocalizations are relatively diverse and increase in intensity in the following order: lip smack/jaw click, growl, snarl, bark. Squeals are heard only in cubs and appear to represent begging to mothers. The whineelicits a variety of reactions depending on the addressee and addressor, but likely functions as an appeasing or reassuring sound. As in striped and brown hyenas, Aardwolves lack a loud, longdistance vocalization like the whoop of spotted hyenas.