How tall is an elephant? Two methods for estimating elephant height

Abstract. Shoulder height is a reliable indicator of age for African elephants (Loxodonta africana), and is therefore an important parameter to be recorded in field studies of population ecology of these pachyderms. However, it can be somewhat difficult to estimate with precision the shoulder height of free-ranging elephants because of several reasons, including the presence of drops and vegetation cover and the potential dangerousness of approaching them in the wild. Here I test two alternative models for estimating shoulder height of elephants. In both models, the equipment needed to generate the height estimates is minimal, and include a telemeter and a digital photo-camera furnished with an ×16 zoom. The models are based respectively on a linear regression approach and on a geometric formula approach, and put into a relationship the linear distance between the observer and the animal, the number of pixels of an elephant silhouette as taken from digital photos, and the absolute height of the animal. Both methods proved to have a very small measurement error, and were thus reliable for field estimates of elephant shoulder heights. The model based on a geometric formula was used to estimate the shoulder height distribution of an elephant population in a savannah region of West Africa (Zakouma National Park, Chad). I demonstrated that Zakouma elephants were among the tallest populations in Africa, with growth rates being highest throughout the first five years of life.

Download Full-text

A songbird adjusts its heart rate and body temperature in response to season and fluctuating daily conditions

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2020.0213 ◽

2021 ◽

Vol 376 (1830) ◽

pp. 20200213 ◽

Cited By ~ 1

Author(s):

Nils Linek ◽

Tamara Volkmer ◽

J. Ryan Shipley ◽

Cornelia W. Twining ◽

Daniel Zúñiga ◽

...

Keyword(s):

Heart Rate ◽

Body Temperature ◽

Environmental Conditions ◽

Field Studies ◽

Weather Extremes ◽

Ambient Temperatures ◽

In The Wild ◽

Radio Transmitters ◽

Save Energy ◽

Free Ranging

In a seasonal world, organisms are continuously adjusting physiological processes relative to local environmental conditions. Owing to their limited heat and fat storage capacities, small animals, such as songbirds, must rapidly modulate their metabolism in response to weather extremes and changing seasons to ensure survival. As a consequence of previous technical limitations, most of our existing knowledge about how animals respond to changing environmental conditions comes from laboratory studies or field studies over short temporal scales. Here, we expanded beyond previous studies by outfitting 71 free-ranging Eurasian blackbirds ( Turdus merula ) with novel heart rate and body temperature loggers coupled with radio transmitters, and followed individuals in the wild from autumn to spring. Across seasons, blackbirds thermoconformed at night, i.e. their body temperature decreased with decreasing ambient temperature, but not so during daytime. By contrast, during all seasons blackbirds increased their heart rate when ambient temperatures became colder. However, the temperature setpoint at which heart rate was increased differed between seasons and between day and night. In our study, blackbirds showed an overall seasonal reduction in mean heart rate of 108 beats min −1 (21%) as well as a 1.2°C decrease in nighttime body temperature. Episodes of hypometabolism during cold periods likely allow the birds to save energy and, thus, help offset the increased energetic costs during the winter when also confronted with lower resource availability. Our data highlight that, similar to larger non-hibernating mammals and birds, small passerine birds such as Eurasian blackbirds not only adjust their heart rate and body temperature on daily timescales, but also exhibit pronounced seasonal changes in both that are modulated by local environmental conditions such as temperature. This article is part of the theme issue ‘Measuring physiology in free-living animals (Part I)’.

Download Full-text

Finding pathways to human–elephant coexistence: a risky business

Oryx ◽

10.1017/s0030605315000344 ◽

2015 ◽

Vol 50 (4) ◽

pp. 713-720 ◽

Cited By ~ 18

Author(s):

Anna Songhurst ◽

Graham McCulloch ◽

Tim Coulson

Keyword(s):

Land Use Planning ◽

Behavioural Change ◽

African Elephants ◽

Buffer Zones ◽

Mixed Effect ◽

Risk Levels ◽

Increase Risk ◽

Elephant Population ◽

Mitigation Techniques ◽

Free Ranging

AbstractFinding ways for people and wildlife to coexist requires affording both parties access to critical resources and space, but also a behavioural change by both to avoid conflict. We investigated pathway use in a population of free-ranging African elephants Loxodonta africana in the Okavango Panhandle, Botswana that share their range with humans in a multi-use, heterogeneous landscape. We used detailed ground surveys to identify and map elephant movement pathways, and mixed-effect models to explore factors influencing elephant numbers and movement behaviour on and around these pathways. We found deviation in pathway use among the elephant population, suggesting behavioural adaptations to avoid human-associated risk: avoiding pathways near settlements, particularly near larger settlements; avoiding pathways close to cultivated land; and adopting a safety-in-numbers strategy when moving through areas of human use. Our findings suggest there is opportunity to capitalize on risk avoidance by elephant populations, to minimize resource-use overlap and reduce conflict between humans and elephants. We discuss a strategy that involves ensuring appropriate protection of elephant pathways in land-use planning, using development-free buffer zones, combined with mitigation techniques along the interface with agricultural lands to increase risk levels and reinforce human–elephant interface boundaries. We recommend further examination of the use of landscape-level mitigation techniques that encourage elephants to use pathways away from human activity and help define spatial boundaries for management of human–elephant conflict in multi-use landscapes.

Download Full-text

Morphometrics of a wild Asian elephant exhibiting disproportionate dwarfism

10.1101/001594 ◽

2013 ◽

Author(s):

Shermin de Silva ◽

Udaya S Weerathunga ◽

Tennekoon Pushpakumara

Keyword(s):

Sri Lanka ◽

Body Length ◽

Single Case ◽

Mammalian Species ◽

Asian Elephant ◽

Average Height ◽

In The Wild ◽

Absolute Height ◽

The Subject ◽

Free Ranging

Dwarfism is a condition characterized by shorter stature, at times accompanied by differential skeletal growth proportions relative to the species-typical physical conformation. Causes vary and well-documented in humans as well as certain mammalian species in captive or laboratory conditions, but rarely observed in the wild. Here we report on a single case of apparent dwarfism in a free-ranging adult male Asian elephant (Elephas maximus) in Sri Lanka, comparing physical dimensions to those of other males in the same population, males in other populations, and records in previous literature. The subject was found to have a shoulder height of approximately 195cm, is shorter than the average height of typical mature males, with a body length of 218cm. This ratio of body length to height deviates from what is typically observed, which is approximately 1:1. In absolute height the subject was similar to the attributes of a captive elephant documented in 1955 in Sri Lanka, also said to be a dwarf, however the two specimens differed in the relative proportions of height vs. body length. The subject also exhibits a slight elongation of the skull. We discuss how this phenotype compares to cases of dwarfism in other non-human animals.

Download Full-text

Spatial relationship between elephant and sodium concentration of water disappears as density increases in Hwange National Park, Zimbabwe

Journal of Tropical Ecology ◽

10.1017/s0266467407004531 ◽

2007 ◽

Vol 23 (6) ◽

pp. 725-728 ◽

Cited By ~ 8

Author(s):

Simon Chamaillé-Jammes ◽

Hervé Fritz ◽

Ricardo M. Holdo

Keyword(s):

National Park ◽

Spatial Relationship ◽

Sodium Concentration ◽

African Elephants ◽

Mineral Concentration ◽

Savanna Vegetation ◽

Selection Processes ◽

Elephant Population ◽

Hwange National Park ◽

Nutrient Selection

African elephants Loxodonta africana (Blumenbach) may profoundly affect vegetation and associated animal bio-diversity in savannas (Conybeare 2004, Skarpe et al. 2004). Understanding the patterns of habitat use by elephants is crucial to predict their impacts on ecosystems (Ben-Shahar 1993, Nelleman et al. 2002), particularly now that many populations are recovering from past culling events or poaching outbreaks (Blanc et al. 2007). Surface water is one of the major constraints on elephant distribution (Chamaillé-Jammes et al. 2007, Stokke & du Toit 2002), and accordingly, elephant impacts are higher in the vicinity of water (Ben-Shahar 1993, de Beer et al. 2006). However, waterhole selection by elephant remains poorly understood. Weir (1972) showed in Hwange National Park (hereafter Hwange NP), Zimbabwe, that elephant numbers at waterholes over 24 h increased with the sodium concentration of water on nutrient-poor Kalahari sands. His work has become widely cited in elephant studies as it remains the only one, to the best of our knowledge, to have studied elephant use of waterholes in relation to the mineral concentration of water. Weir's work, however, took place when elephant densities in Hwange NP were low, likely below 0.5 elephants km−2 as estimated by aerial censuses (Williamson 1975). Since then, the elephant population has increased dramatically, particularly since the halt to culling operations in 1986 (Chamaillé-Jammes 2006, Cumming 1981). The present elephant density is much higher, estimated to be over 2 elephants km−2 (Chamaillé-Jammes et al. 2007, in press), and is one of the highest in the world (Blanc et al. 2007). Increased density may modify ecological constraints and affect the hierarchy of habitat selection processes (Morris 2003), and the extent to which water-nutrient selection still constrains elephant distribution at high population density – when their impact on savanna vegetation is the highest – remains unknown.

Download Full-text

Into the wild: developing field tests to examine the link between elasmobranch personality and laterality

Behaviour ◽

10.1163/1568539x-00003373 ◽

2016 ◽

Vol 153 (13-14) ◽

pp. 1777-1793 ◽

Cited By ~ 9

Author(s):

Evan E. Byrnes ◽

Catarina Vila Pouca ◽

Sherrie L. Chambers ◽

Culum Brown

Keyword(s):

Personality Traits ◽

Field Tests ◽

Animal Personality ◽

Field Studies ◽

Individual Level ◽

In The Wild ◽

Port Jackson ◽

The Relationship

The field of animal personality has received considerable attention in past decades, yet few studies have examined personality in the wild. This study investigated docility, a measure of boldness, in two Port Jackson shark (Heterodontus portusjacksoni) populations using field tests, and if laterality differences explained docility levels. We developed a struggle test as an assay for docility, which is particularly amenable to field studies. The struggle test was effective, and repeatable inter-individual docility differences were observed. Sex, but not population, influenced docility scores, with male sharks being less docile than females. This difference is likely due to the contrasting role each sex plays during mating. We also found individualized lateralization. However, no individual-level relationship between lateralization and docility was detected. Despite reported links between laterality and some personality traits, the relationship between laterality and boldness remains inconclusive in sharks. Further studies will prove essential to clarify the mechanisms behind personality traits in vertebrates.

Download Full-text

Novelty at dawn: Exploration, low neophobia and crepuscular activity in a wild Common Buzzard (Buteo buteo)

Avian Biology Research ◽

10.1177/17581559211052422 ◽

2021 ◽

pp. 175815592110524

Author(s):

Berenika Mioduszewska ◽

Mark O’Hara ◽

Rafał Stryjek

Keyword(s):

Foraging Ecology ◽

Natural Habitat ◽

Field Studies ◽

Field Method ◽

Cognitive Testing ◽

Research Attention ◽

Predator Species ◽

Common Buzzard ◽

Buteo Buteo ◽

Free Ranging

Raptor cognition has received limited research attention, despite the importance of comparative investigations for reconstructing the evolution of complex cognition. Field studies provide essential ecological context for cognition in the natural habitat, although this approach is often challenging due to extensive procedures involved in cognitive testing. One predisposition suggested to contribute to problem-solving behaviour is the response to novel stimuli. In this pilot study, a novel object test was conducted on an outdoor feeding platform to assess the neotic responses of a single wild free-ranging Common Buzzard ( Buteo buteo), a generalist/opportunist diurnal predator species. Additionally, data on its daily activity were collected. As predicted, the subject expressed low neophobia and some exploratory behaviours. Interestingly, it repeatedly arrived on the platform in low light conditions. This study highlights the influence of foraging ecology on cognitive predispositions and offers a field method for research on raptor cognition.

Download Full-text

Seroprevalence of Mycobacterium tuberculosis Complex in Free-Ranging African Elephants (Loxodonta africana) in Kruger National Park, South Africa

Journal of Wildlife Diseases ◽

10.7589/2018-12-292 ◽

2019 ◽

Vol 55 (4) ◽

pp. 923 ◽

Cited By ~ 2

Author(s):

Tanya J. Kerr ◽

Candice R. de Waal ◽

Peter E. Buss ◽

Jennifer Hofmeyr ◽

Konstantin P. Lyashchenko ◽

...

Keyword(s):

South Africa ◽

Mycobacterium Tuberculosis ◽

National Park ◽

Mycobacterium Tuberculosis Complex ◽

Loxodonta Africana ◽

Kruger National Park ◽

African Elephants ◽

Tuberculosis Complex ◽

Free Ranging

Download Full-text

Rapid Detection of Serum Antibody by Dual-Path Platform VetTB Assay in White-Tailed Deer Infected with Mycobacterium bovis

Clinical and Vaccine Immunology ◽

10.1128/cvi.00120-13 ◽

2013 ◽

Vol 20 (6) ◽

pp. 907-911 ◽

Cited By ~ 18

Author(s):

Konstantin P. Lyashchenko ◽

Rena Greenwald ◽

Javan Esfandiari ◽

Daniel J. O'Brien ◽

Stephen M. Schmitt ◽

...

Keyword(s):

Diagnostic Accuracy ◽

Mycobacterium Bovis ◽

Skin Testing ◽

Serum Antibody ◽

Antibody Responses ◽

Antibody Detection ◽

Serum Samples ◽

Content Type ◽

In The Wild ◽

Free Ranging

ABSTRACTBovine tuberculosis (TB) in cervids remains a significant problem affecting farmed herds and wild populations. Traditional skin testing has serious limitations in certain species, whereas emerging serological assays showed promising diagnostic performance. The recently developed immunochromatographic dual-path platform (DPP) VetTB assay has two antigen bands, T1 (MPB83 protein) and T2 (CFP10/ESAT-6 fusion protein), for antibody detection. We evaluated the diagnostic accuracy of this test by using serum samples collected from groups of white-tailed deer experimentally inoculated withMycobacterium bovis,M. aviumsubsp.paratuberculosis, orM. bovisBCG Pasteur. In addition, we used serum samples from farmed white-tailed deer in herds with no history of TB, as well as from free-ranging white-tailed deer culled during field surveillance studies performed in Michigan known to have bovine TB in the wild deer population. The DPP VetTB assay detected antibody responses in 58.1% of experimentally infected animals within 8 to 16 weeks postinoculation and in 71.9% of naturally infected deer, resulting in an estimated test sensitivity of 65.1% and a specificity of 97.8%. The higher seroreactivity found in deer with naturally acquiredM. bovisinfection was associated with an increased frequency of antibody responses to the ESAT-6 and CFP10 proteins, resulting in a greater contribution of these antigens, in addition to MPB83, to the detection of seropositive animals, compared with experimentalM. bovisinfection. Deer experimentally inoculated with eitherM. aviumsubsp.paratuberculosisorM. bovisBCG Pasteur did not produce cross-reactive antibodies that could be detected by the DPP VetTB assay. The present findings demonstrate the relatively high diagnostic accuracy of the DPP VetTB test for white-tailed deer, especially in the detection of naturally infected animals.

Download Full-text