Diet of the short-beaked echidna (Tachyglossus aculeatus) in the Tasmanian Southern Midlands

Sprent, Jenny; Nicol, Stewart C.

doi:10.1071/am15023

Cited by 14 publications

(14 citation statements)

References 17 publications

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“…Thus, it is argued that the relatively large brain sizes of humans and other primates could not have been achieved without a shift to a high-quality diet, allowing a reduction in gut size. It is doubly puzzling then that the short-beaked echidna has a brain of similar size to that of a similar sized eutherian carnivore but a metabolic rate only 30% of the eutherian prediction and has a diet of extremely low energy density and digestibility (Sprent and Nicol, 2016 ). Echidnas have brain size to BMR relationships similar to those of primates, suggesting that there must be very considerable fitness benefits for the echidnas to maintain such large brains, i.e., the cognitive benefits must outweigh the metabolic costs (Isler and van Schaik, 2006 ).…”

Section: Brain and Energeticsmentioning

confidence: 99%

Energy Homeostasis in Monotremes

Nicol

2017

Front. Neurosci.

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In 1803, the French anatomist Étienne Geoffroy Saint-Hilaire decided that the newly described echidna and platypus should be placed in a separate order, the monotremes, intermediate between reptiles and mammals. The first physiological observations showed monotremes had low body temperatures and metabolic rates, and the consensus was that they were at a stage of physiological development intermediate between “higher mammals” and “lower vertebrates.” Subsequent studies demonstrated that platypuses and echidnas are capable of close thermoregulation in the cold although less so under hot conditions. Because the short-beaked echidna Tachyglossus aculeatus, may show very large daily variations in body temperature, as well as seasonal hibernation, it has been suggested that it may provide a useful model of protoendotherm physiology. Such analysis is complicated by the very significant differences in thermal relations between echidnas from different climates. In all areas female echidnas regulate Tb within 1°C during egg incubation. The lactation period is considered to be the most energetically expensive time for most female mammals but lactating echidnas showed no measurable difference in field metabolic rate from non-lactating females, while the lactation period is more than 200 days for Kangaroo Island echidnas but only 150 days in Tasmania. In areas with mild winters echidnas show reduced activity and shallow torpor in autumn and early winter, but in areas with cold winters echidnas enter true hibernation with Tb falling as low as 4.5°C. Monotremes do not possess brown adipose tissue and maximum rates of rewarming from hibernation in echidnas were only half those of marmots of the same mass. Although echidnas show very large seasonal variations in fat stores associated with hibernation there is no relationship between plasma leptin and adiposity. Leptin levels are lowest during post-reproductive fattening, supporting suggestions that in evolutionary terms the anorectic effects of leptin preceded the adiposity signal. BMR of platypuses is twice that of echidnas although maximum metabolism is similar. High levels of thyroid hormones in platypuses may be driving metabolism limited by low body temperature. Monotremes show a mosaic of plesiomorphic and derived features but can still inform our understanding of the evolution of endothermy.

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Section: Brain and Energeticsmentioning

confidence: 99%

Energy Homeostasis in Monotremes

Nicol

2017

Front. Neurosci.

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“…In the wild, ants and termites are the main food sources for the echidna [Abensperg‐Traun, ; Griffiths et al, ; Abensperg‐Traun and De Boer, ; Sprent and Nicol, ]. An ingestion ratio of 77:23 termite:ants is known, but the ratio can vary depending on the animal's location, and also fluctuate seasonally, reflecting relative abundance of the prey items [Abensperg‐Traun and De Boer, ].…”

Section: Demonstration Of Efficacymentioning

confidence: 99%

Digestibility of a new diet for captive short-beaked echidnas (Tachyglossus aculeatus)

et al. 2017

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Short-beaked echidnas (Tachyglossus aculeatus) are myrmecophages, or ant and termite insectivore specialists, and replicating their exact diet in captivity is problematic. Diets for captive animals often incorporate raw meat, eggs and cat food mixed together with water, and vitamin and mineral supplements. These diets have promoted a number of health problems in captive echidnas, such as gastritis, cystitis, gut impaction, obesity, and diarrhea. A manufactured diet was designed and three echidnas from two zoos were transitioned onto this diet to assess the acceptability and digestibility of this diet for echidnas. The new "test" diet was readily accepted by the echidnas with a 1 week transition period. Daily digestible energy intake was 280 kJ kg d , similar to another myrmecophagous species. Digestibility values were above 74% for all macronutrients. It was determined that this diet was an acceptable replacement for the previous diets and it was decided that the remaining echidnas at both institutions would be transitioned to the new diet. The diet will also be used for wild echidnas being rehabilitated in the zoo hospitals prior to release and commercially available within Australia. Further data are being collected to assess the use of this diet for seasonal weight management, transitioning hand-reared puggles and effects on gastrointestinal tract health. Zoo Biol. 36:56-61, 2017. © 2017 Wiley Periodicals, Inc.

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“…Diet is a major determinant of the bacterial communities in the gut microbiome, with many phylogenetically distant mammals clustering together as carnivores, omnivores, and herbivores, with herbivores even forming distinct groups of foregut and hindgut fermenters based on the location and the composition of these microbes living in their gut ( Ley et al, 2008 ). Echidnas are often mistakenly characterised as myrmecophagous animals (exclusively ant and termite eaters) but instead eat a wide variety of invertebrates including (but not limited to) ants, termites, beetles, worms, and a range of insect larvae ( Griffiths, 1968 ; Smith et al, 1989 ; Sprent and Nicol, 2016 ) and have even been associated with the distribution of mycorrhizal fungi ( Feuerherdt et al, 2005 ). Echidnas are opportunistic foragers, and their diets will change depending on the food availability, season and temperature ( Smith et al, 1989 ; Sprent and Nicol, 2016 ); however, echidnas diet across their wide habitat types has yet to be characterised in detail.…”

Section: Introductionmentioning

confidence: 99%

Characterising the Gut Microbiomes in Wild and Captive Short-Beaked Echidnas Reveals Diet-Associated Changes

et al. 2022

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The gut microbiome plays a vital role in health and wellbeing of animals, and an increasing number of studies are investigating microbiome changes in wild and managed populations to improve conservation and welfare. The short-beaked echidna (Tachyglossus aculeatus) is an iconic Australian species, the most widespread native mammal, and commonly held in zoos. Echidnas are cryptic animals, and much is still unknown about many aspects of their biology. Furthermore, some wild echidna populations are under threat, while echidnas held in captivity can have severe gastric health problems. Here, we used citizen science and zoos to collect echidna scats from across Australia to perform the largest gut microbiome study on any native Australian animal. Using 16S rRNA gene metabarcoding of scat samples, we characterised and compared the gut microbiomes of echidnas in wild (n = 159) and managed (n = 44) populations, which were fed four different diets. Wild echidna samples were highly variable, yet commonly dominated by soil and plant-fermenting bacteria, while echidnas in captivity were dominated by gut commensals and plant-fermenting bacteria, suggesting plant matter may play a significant role in echidna diet. This work demonstrates significant differences between zoo held and wild echidnas, as well as managed animals on different diets, revealing that diet is important in shaping the gut microbiomes in echidnas. This first analysis of echidna gut microbiome highlights extensive microbial diversity in wild echidnas and changes in microbiome composition in managed populations. This is a first step towards using microbiome analysis to better understand diet, gastrointestinal biology, and improve management in these iconic animals.

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Diet of the short-beaked echidna (Tachyglossus aculeatus) in the Tasmanian Southern Midlands

Cited by 14 publications

References 17 publications

Energy Homeostasis in Monotremes

Energy Homeostasis in Monotremes

Digestibility of a new diet for captive short-beaked echidnas (Tachyglossus aculeatus)

Characterising the Gut Microbiomes in Wild and Captive Short-Beaked Echidnas Reveals Diet-Associated Changes

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