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

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Date
2004
Authors
Smith, Yanna
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Publisher
University of the Free State
Abstract
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.
Afrikaans: Aspekte van die gedrag van 'n klein trop Afrika-leeus (Panthera leo) in die Intu Afrika Kalahari Wildreservaat is in die suidelike Kalahari van Namibië ondersoek. Die voltallige leeutrop het uit drie volwassenes, twee mannetjies en 'n wyfie, asook 'n welpie van elke geslag, bestaan. Veldwerk is oor tydperke van ses weke gedurende die midwinter (Mei tot Julie 2003) en weer gedurende die midsomer (Februarie en Maart 2004) uitgevoer. Veldopnames het alternatiewelik gedurende die dag (sonop tot sononder) en nag (sononder tot sonop) plaasgevind. Liggaamsoppervlaktemperatuur van die leeuwyfie en oudste mannetjie is deur middel van Thermocron iButtonsTM wat onderhuids in die nek, stert en lieste van elke individu ingeplant is, bepaal. Gedragspatrone wat algemeen voorgekom het en as normale gedrag van Kalahari-leeus beskou kan word, sluit reukafbakening, territoriale patrollering, krap van spesifieke bome, boomklim, kooperatiewe jag, sandbedekking van karkasse en grasbenutting in. Ongewone gedrag, moontlik as gevolg van die ongelyke geslagsverhouding ten gunste van mannetjies, het herhaalde dominante/onderdanige interaksies, asook aanhoudende reukafbakening en lipkrulreaksies, ingesluit. Berekende assosiasie-indekse was ook oneweredig aangesien die jonger leeumannetjie weens sy hegte band met die wyfie, sy suster, nie alleen 'n duidelike familievoorkeur vir die welpies getoon het nie, maar ook allotrope ouersorg deur die rol van "Tante" te vervul. Aktiwiteitspatrone toon 'n negatiewe verwantskap met toenemende temperatuur gedurende beide seisoene, maar heers veral gedurende die warm somermaande. 'n Duidelike afname in aktiwiteite kom teen die middel van die dag gedurende die winter, maar vroegoggend (9 - 10 h) gedurende die somer voor. Tydens laasgenoemde seisoen vind hyging ten koste van liggaamsversorging en die vorming van bondgenootskappe tussen individuele lede van die trop plaas. Aktiwiteite gedurende die winternagte was baie beperk, waarskynlik as 'n gevolg van die lae temperature, terwyl verhoogte aktiwiteite tydens die somer voorgekom het. Vroegoggend sonbadperiodes op die kruine van duine was oor die algemeen meer omvattend gedurende die winter as in die somer. Resultate met betrekking tot die aktiwiteitspatrone van die welpies is in ooreenstemming met dié van die volwassenes. Temperatuurlesings van die iButtons dui op relatief stabiele oppervlaktemperature, veral in die neksone met sy dikker vel en groter mate van gespierdheid. Die stertstreek toon groter temperatuurvariasie, moontlik as gevolg van die voortdurende blootstelling en uitgebreide bloedvatvoorsiening soos deur disseksie bepaal. 'n Groot aantaloppervlakkige maar kleiner bloedvate is dorsaal en lateraalop die karkas aangetref en is waarskynlik by termoreguleering betrokke. iButton-data van die lieste kan nie as afdoende beskou word nie, maar blootstelling van die lieste het toegeneem namate temperature gestyg het, veral met vol pense gedurende die somer. Met leë pense is die lieste nooit onder 17 °C gedurende die winter of somer blootgestel nie. Termoregulerende vermydingsgedrag is by temperature hoër as 25 °C tydens beide seisoene waargeneem. By omgewingstemperature bo 33 °C is gedragstermoregulering ten gunste van fisiologiese meganismes (hyging) laat vaar, voldoende aanduiding dat die termoneutrale sone van die Kalaharileeutrop tussen 25°C 33 °C geleë is. Gedragspatrone, die geringe gebruik van water vir verdampingsafkoeling en die klaarblyklike benutting van prooibloed en -liggaamsvloeistowwe as waterbron dien as aanduiding dat die Afrika-leeu nie van drinkwater afhanklik is nie. Afmetings om die relatiewe dikte van die medulla en dus die nierfunksie te bepaal, dui nie op 'n besondere vermoë tot waterresorpsie nie. Sweetkliere van katagtiges kom slegs tussen die tone voor, en ondersoek van die pootkussinkies toon dan dat dit uit ekkriene kliere bestaan. Vergeleke met gepubliseerde data was die ekto- en endoparasietgetalle van die leeus relatief lag, waarskynlik as gevolg van die ariede habitat en die oorspronklike ontwurming van volwasse individue vóór die aanvang van die huidige studie. Slegs een ekto- (steekvlieg) en vier endoparasietsoorte (nematodes en koksidieë) is versamel, almal tipiese parasiete van Afrika-leeus. Geen tampan is versamel nie, en het dus geen invloed op die gedrag van die leeutrop uitgeoefen nie.
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Keywords
Lions -- Behavior -- Namibia, Lions -- Habitat -- Namibia, African lions (Panthera feo), Dissertation (M.Sc. (Zoology and Entomology))--University of the Free State, 2004
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