Why are aardvarks nocturnal

With deserts and drylands expanding across much of Africa, climate change might threaten the aardvark itself as well as the many animals reliant on aardvark burrows as a cool shelter from rising temperatures. However, this pattern changed during two severe summer droughts that occurred in the Kalahari during our study. Using remotely-sensed vegetation data recorded by NASA satellites and our own camera trap footage and logger data, we showed that these dramatic changes in body temperature and activity of aardvarks were related to the availability of grass, on which their ant and termite prey rely.

When grass was scarce during droughts, the ant and termite prey became inaccessible to aardvarks, preventing them from meeting their daily energy requirements. As their body reserves declined, aardvarks were unable to sustain the energy costs of maintaining warm and stable body temperatures and shifted their activity to the warmer daytime. Shifting activity to the warmer daytime while food is scarce can save energy that would otherwise be spent on staying warm during cold nights.

But, for our aardvarks, even these energy savings were insufficient during drought, when the ground was bare and the ant and termite prey inaccessible. As a result, seven of our twelve study aardvarks and many others died, presumably from starvation.

Though aardvarks do scent-mark their turf, the actual size of their territory is unclear. While aardvarks do face some habitat reduction due to human population encroachment and activities, they are not considered heavily threatened.

Aardvarks are widely spread throughout Africa, inhabiting most regions south of the Sahara. Aardvarks prefer living on flat territory with few rocks, but can be found anywhere their primary food source—ants and termites—thrive, from savanna to forest to grassland.

Aardvarks are myrmecophagous—that is, they specialize in eating ants and termites. They have a highly developed sense of smell that enables them to find these insects underground, and they have long tongues that easily slip inside termite mounds and ant nests. An aardvark will spend all night foraging for the hundreds of thousands of ants or termites it needs to fill its stomach. Aardvarks have a gestation period of about 35 weeks, and give birth to one or two young at a time. Little else is known about aardvark breeding behavior, particularly in the wild.

Journal List Front Physiol v. Front Physiol. Published online Jul 7. Author information Article notes Copyright and License information Disclaimer. This article was submitted to Environmental, Aviation and Space Physiology, a section of the journal Frontiers in Physiology. Received Dec 20; Accepted May The use, distribution or reproduction in other forums is permitted, provided the original author s and the copyright owner s are credited and that the original publication in this journal is cited, in accordance with accepted academic practice.

No use, distribution or reproduction is permitted which does not comply with these terms. Abstract Shifting activity to cooler times of day buffers animals from increased heat and aridity under climate change. Keywords: body temperature, heterothermy, biologging, behavioural flexibility, climate change. Introduction Large mammals that reproduce slowly and are unable to move to more suitable surroundings require flexibility in behaviour and physiology to survive in rapidly changing environments Fuller et al.

Climatic Variables We recorded the air temperature at the study site at min intervals using a weather station Watchdog , Spectrum Technologies Inc. Aardvark Capture and Surgery Over a 3. Time of Emergence and Return to Burrows We set up camera traps MMS wireless scouting camera, LTLMC HD series, Ltl Acorn, China outside aardvark burrows to determine the exact time of emergence from and return to a burrow after foraging if the aardvark returned to the same burrow from which it had emerged.

Results Environmental Conditions Air temperatures at Tswalu varied seasonally, but interannual differences were small Figure 1A , with annual summer air temperature maxima ranging between Open in a separate window.

Patterns of Aardvark Body Temperatures Body temperatures of study aardvarks ranged from Significant P -values are italicised for ease of reference. Activity Patterns Locomotor activity of aardvarks over h periods was biphasic, with activity typically high in the scotophase and low in the photophase, but with brief inactive bouts during the active phase, and brief active bouts during the inactive phases as shown for a representative aardvark A08 , Figure 3.

No activity data were available from March to June For time of emergence and return, camera trap data were included in the dataset on days on which no biologger data were recorded May to September Patterns of h Body Temperature and Activity To visualise how low resource availability during the drought influenced body temperature and activity of our aardvarks, we graphed Figure 5 aardvark activity and body temperature, as a function of time of day, for a winter and summer month, during a drought year rainfall in the lowest quartile of a year record and during a non-drought year rainfall in the highest quartile of a year record.

Data Availability Statement The data sets analysed for this study are available on request to the corresponding author.

Author Contributions All authors contributed to study design, field work and data interpretation, edited the manuscript, approved the final version of the manuscript, and agreed to be held accountable for the content therein. Conflict of Interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Acknowledgments We thank Oppenheimer Generations especially Dr. References Acker J. Eos Trans. Union 88 14— Pretoria: Agri SA Research. Convergence 12 : 2. Nutritional physiology and ecology of wildlife in a changing world. Adaptation strategies to seasonal changes in environmental conditions of a domesticated horse breed, the Shetland pony Equus ferus caballus. To use or not to use torpor? Activity and body temperature as predictors.

Naturwissenschaften 94 — Effects of lactation on feeding behaviour and habitat use in wild red deer hinds. Dung beetle assemblage structure in Tswalu Kalahari reserve: responses to a mosaic of landscape types, vegetation communities, and dung types. Climate and the match or mismatch between predator requirements and resource availability. Projections of rapidly rising surface temperatures over Africa under low mitigation. Adaptation to heat and water shortage in large, arid-zone mammals.

Physiology 29 — Towards a mechanistic understanding of the responses of large terrestrial mammals to heat and aridity associated with climate change. Responses 3 : 10 Die nesstelsel van die grasdraertermiet Hodotermes mossambicus Hagen Isoptera en aspekte rakende bestryding.

Energy, water, and broad-scale geographic patterns of species richness. Ecology 84 — Body temperature and metabolic rate during natural hypothermia in endotherms. B — Heterothermy in large mammals: inevitable or implemented? Variation in the daily rhythm of body temperature of free-living Arabian oryx Oryx leucoryx : does water limitation drive heterothermy? Activity re-assignment and microclimate selection of free-living Arabian oryx: responses that could minimise the effects of climate change on homeostasis?

Zoology — Does size matter? Comparison of body temperature and activity of free-living Arabian oryx Oryx leucoryx and the smaller Arabian sand gazelle Gazella subgutturosa marica in the Saudi desert. B Biochem. Working for food shifts nocturnal mouse activity into the day. PLoS One 6 : e Dissertation, University of the Free State, Bloemfontein. Optimal foraging, predation risk and territory defence.

Ardea 68 83— Time and ecological resilience: can diurnal animals compensate for climate change by shifting to nocturnal activity? Behavioural decisions made under the risk of predation: a review and prospectus.

Ant composition and activity patterns as determined by pitfall trapping and other methods in three habitats in the semi-arid Karoo. Arid Environ. Seasonal change in the activity pattern of Dipodomys spectabilis. Pretoria: Dept.

Thermoregulatory plasticity in free-ranging vervet monkeys, Chlorocebus pygerythrus. Minimum daily core body temperature in western grey kangaroos decreases as summer advances: a seasonal pattern, or a direct response to water, heat or energy supply?

Body size and activity times mediate mammalian responses to climate change. Behavioral flexibility of vervet monkeys in response to climatic and social variability. Assessing the reliability of biologger techniques to measure activity in a free-ranging primate. Adaptive heterothermy and selective brain cooling in arid-zone mammals.

Part B Biochem. Revisiting concepts of thermal physiology: predicting responses of mammals to climate change. Aspekte van die gedrag van die werkers van die grasdraertermiet, Hodotermes mossambicus Hagen , in die veld. A study of the food eaten by a field population of the harvester termite, Hodotermes mossambicus Hagen and its relation to population density. Part B: Regional Aspects. Cambridge: Cambridge University Press; , — Desert ecosystems: environment and producers. Influence of season, habitat, temperature, and invertebrate availability on nocturnal activity of the New Zealand long-tailed bat Chalinolobus tuberculatus.

New Zeal. Dissertation: University Pretoria, Pretoria. Some external characters of Orycteropus afer. London 46 — Seasonal and daily activity patterns of free-living Eurasian lynx Lynx lynx in relation to availability of kills. Warming, plant phenology and the spatial dimension of trophic mismatch for large herbivores. B Biol. They will then move at a slow trot looking for food. When aardvarks sleep, they block out the entrance to their burrow, leaving only a very small opening at the top, and curl into a tight ball.

They frequently dig new burrows, which many other animals use the past burrows as shelters. Females tend to stay in the same area whereas males wander more. This species is specialized for eating termites. They move from one termite mound to another, dismantling the hills with their powerful claws.

Insects are trapped by their long protractile tongue as long as 30 centimeters , which is covered with thick, sticky saliva. Their impeccable sense of smell allows them to catch termites outside of the mounds.

Sometimes they will press their snout against an opening in a mound and suck up the termites. They are quite versatile in their housing choices and can be found in a broad range of regions, from dry savannas to rainforests.

Where there are sufficient termites for food, and soft ground for burrowing, like sandy or clay soil, you will find aardvarks. Despite being speedy, powerful diggers, they will abandon areas where the soil is too hard and instead will favor areas where the digging is easier. Unleash more canine heroes to save elephants.