Aspects of the behaviour of the African lion (Panthera leo) in an extreme environment

English: Aspects of the behaviour of a small pride of African lions (Panthera feo) were investigated at Intu Afrika Kalahari Game Reserve in the Southern Kalahari in Namibia. The full pride consisted of three adults, two males and a female, as well as a cub of each sex. Fieldwork was conducted for periods of six weeks during midwinter (May to July 2003) and again during midsummer (February and March 2004). Trials consisted of alternating continuous observational periods during daytime (sunrise to sunset) and nighttime (sunset to sunrise). Body surface temperatures of the lioness and the oldest male were measured by Thermocron iButtonsTM, implanted subcutaneously into the neck, tail and loin regions of each individual. Behavioural patterns which commonly occurred and can be considered conventional Kalahari lion behaviour, included scent marking, territorial patrols, raking of specific trees, tree-climbing, co-operative hunting, covering of carcasses with sand and grazing. Unconventional behaviour, possibly as a result of the skewed sex ratio favouring the males, included frequent dominant/submissive interactions as well as incessant scent marking and flehmen responses. Calculated association indices were disproportionate, the younger male not only demonstrating strong kin selection for the cubs as a result of his bond with the female, his sister, but also exhibiting alloparental care by assuming the role of "Auntie'. Time-energy budgets demonstrated a negative relationship with increasing temperature during both seasons, being more prevalent during the hotter summer months. A distinct decrease in activity set in around midday during winter and during early morning (9 - 10 h) in summer. During the latter season, behaviours such as grooming and bonding between individual pride members were sacrificed for panting. Nighttime activity during winter was very low, probably as a result of the low temperatures, whereas greater activity was shown during summer. Periods of sunbathing on the dune crests during early mornings were generally more extensive during winter than in summer. The results for the time-energy budgets of the cubs were in accordance with that of the adults. Temperature measurement by the iButtons indicated relative constancy in surface temperature particularly in the neck region, most likely due to the thicker skin and greater muscularisation. The tail region demonstrated greater temperature variation possibly as a result of its constant exposure and extensive vascularisation as demonstrated by dissection. A large number of superficial small-diameter vessels were found dorsally and laterally on the carcass, probably used for thermoregulation. The loin iButlon data was not demonstrative, but exposure of loins increased as temperature increased, specifically with full bellies during summer. Loins were not exposed with empty bellies under 17°C during both winter and summer. Thermoregulatory "escape" behaviour was observed at temperatures greater than 25 °C during both seasons. At ambient temperatures above 33°C thermoregulatory behaviour was abandoned in favour of physloloqical mechanisms (panting), thereby indicating that the thermoneutral zone of the Kalahari pride lies between 25 and 33°C. Behavioural adaptations, a low use of water for evaporative cooling and the apparent sourcing of water from prey blood and body fluids indicate that the African lion may be independent of drinking water. Measurements to determine of the relative medullary thickness and thus the extent of kidney function, did not show a specific capacity for water resorption. Sweat glands are only present interdigitally in felids and examination of the paw pads showed these to be eccrine glands. Ecto- and endoparasite numbers of the lions were found to be relatively low when compared to published data, probably as a result of the arid habitat and the original deworming of the adult individuals prior to the inception of the present study. Only one species of ecto- (biting fly) and four species of endoparasite (nematodes and coccidians) were collected, all of which are typical African lion parasites. No tampans were collected and, therefore, had no impact on the behaviour of the pride.