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Ken W.s. Ashwell - One of the best experts on this subject based on the ideXlab platform.
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Brain and behaviour of living and extinct Echidnas.
Zoology (Jena Germany), 2014Co-Authors: Ken W.s. Ashwell, Craig D. Hardman, Anne M. MusserAbstract:Abstract The Tachyglossidae (long- and short-beaked Echidnas) are a family of monotremes, confined to Australia and New Guinea, that exhibit striking trigeminal, olfactory and cortical specialisations. Several species of long-beaked Echidna ( Zaglossus robusta , Zaglossus hacketti , Megalibgwilia ramsayi ) were part of the large-bodied (10 kg or more) fauna of Pleistocene Australasia, but only the diminutive (2–7 kg) Tachyglossus aculeatus is widespread today on the Australian mainland. We used high-resolution CT scanning and other osteological techniques to determine whether the remarkable neurological specialisations of modern Echidnas were also present in Pleistocene forms or have undergone modification as the Australian climate changed in the transition from the Pleistocene to the Holocene. All the living and extinct Echidnas studied have a similar pattern of cortical gyrification that suggests comparable functional topography to the modern short-beaked form. Osteological features related to olfactory, trigeminal, auditory and vestibular specialisation (e.g., foramina and cribriform plate area, osseous labyrinth topography) are also similar in living and extinct species. Our findings indicate that despite differences in diet, habitat and body size, the suite of neurological specialisations in the Tachyglossidae has been remarkably constant: encephalisation, sensory anatomy and specialisation (olfactory, trigeminal, auditory and vestibular), hypoglossal nerve size and cortical topography have all been stable neurological features of the group for at least 300,000 years.
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Distinct development of the trigeminal sensory nuclei in platypus and Echidna.
Brain behavior and evolution, 2012Co-Authors: Ken W.s. Ashwell, Craig D. HardmanAbstract:Both lineages of the modern monotremes have been reported to be capable of electroreception using the trigeminal pathways and it has been argued that electroreception arose in an aquatic platypus-like ancestor of both modern monotreme groups. On the other hand, the trigeminal sensory nuclear complex of the platypus is highly modified for processing tactile and electrosensory information from the bill, whereas the trigeminal sensory nuclear complex of the short-beaked Echidna (Tachyglossus aculeatus) is not particularly specialized. If the common ancestor for both platypus and Echidna were an electroreceptively and trigeminally specialized aquatic feeder, one would expect the early stages of development of the trigeminal sensory nuclei in both species to show evidence of structural specialization from the outset. To determine whether this is the case, we examined the development of the trigeminal sensory nuclei in the platypus and short-beaked Echidna using the Hill and Hubrecht embryological collections. We found that the highly specialized features of the platypus trigeminal sensory nuclei (i.e. the large size of the principal nucleus and oral part of the spinal trigeminal nuclear complex, and the presence of a dorsolateral parvicellular segment in the principal nucleus) appear around the time of hatching in the platypus, but are never seen at any stage in the Echidna. Our findings support the proposition that the modern Echidna and platypus are derived from a common ancestor with only minimal trigeminal specialization and that the peculiar anatomy of the trigeminal sensory nuclei in the modern platypus emerged in the ornithorhynchids after divergence from the tachyglossids.
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Development of the dorsal and ventral thalamus in platypus (Ornithorhynchus anatinus) and short-beaked Echidna (Tachyglossus aculeatus)
Brain Structure and Function, 2012Co-Authors: Ken W.s. AshwellAbstract:The living monotremes (platypus and Echidnas) are distinguished from therians as well as each other in part by the unusual structure of the thalamus in each. In particular, the platypus has an enlarged ventral posterior (VP) nucleus reflecting the great behavioural importance of trigeminosensation and electroreception. The embryological collections of the Museum für Naturkunde in Berlin were used to analyse the development of the dorsal thalamus and ventral thalamus (prethalamus) in both species. Prosomeric organization of the forebrain emerged at 6 mm crown-rump length (CRL), but thalamic neurogenesis did not commence until about 8–9 mm CRL. Distinctive features of the dorsal thalamus in the two species began to emerge after hatching (about 14–15 mm CRL). During the first post-hatching week, dense clusters of granular cells aggregated to form the VP of the platypus, whereas the VP complex of the Echidna remained smaller and divided into distinct medial and lateral divisions. At the end of the first post-hatching week, the thalamocortical tract was much larger in the platypus than the Echidna. The dorsal thalamus of the platypus is essentially adult-like by the sixth week of post-hatching life. The similar appearance of the dorsal thalamus in the two species until the time of hatching, followed by the rapid expansion of the VP in the platypus, is most consistent with ancestral platypuses having undergone changes in the genetic control of thalamic neurogenesis to produce a large VP for trigeminal electroreception after the divergence of the two lineages of monotreme.
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distinct development of peripheral trigeminal pathways in the platypus ornithorhynchus anatinus and short beaked Echidna tachyglossus aculeatus
Brain Behavior and Evolution, 2012Co-Authors: Ken W.s. Ashwell, Craig D. Hardman, Peter GiereAbstract:The extant monotremes (platypus and Echidnas) are believed to all be capable of electroreception in the trigeminal pathways, although they differ significantly in the number and distribution of electroreceptors. It has been argued by some authors that electroreception was first developed in an aquatic environment and that Echidnas are descended from a platypus-like ancestor that invaded an available terrestrial habitat. If this were the case, one would expect the developmental trajectories of the trigeminal pathways to be similar in the early stages of platypus and short-beaked Echidna development, with structural divergence occurring later. We examined the development of the peripheral trigeminal pathway from snout skin to trigeminal ganglion in sectioned material in the Hill and Hubrecht collections to test for similarities and differences between the two during the development from egg to adulthood. Each monotreme showed a characteristic and different pattern of distribution of developing epidermal sensory gland specializations (electroreceptor primordia) from the time of hatching. The cross-sectional areas of the trigeminal divisions and the volume of the trigeminal ganglion itself were also very different between the two species at embryonic ages, and remained consistently different throughout post-hatching development. Our findings indicate that the trigeminal pathways in the short-beaked Echidna and the platypus follow very different developmental trajectories from the earliest ages. These findings are more consistent with the notion that the platypus and Echidna have both diverged from an ancestor with rudimentary electroreception and/or trigeminal specialization, rather than the contention that the Echidna is derived from a platypus-like ancestor.
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Development of the olfactory pathways in platypus and Echidna.
Brain behavior and evolution, 2011Co-Authors: Ken W.s. AshwellAbstract:The two groups of living monotremes (platypus and Echidnas) have remarkably different olfactory structures in the adult. The layers of the main olfactory bulb of the short-beaked Echidna are extensively folded, whereas those of the platypus are not. Similarly, the surface area of the piriform cortex of the Echidna is large and its lamination complex, whereas in the platypus it is small and simple. It has been argued that the modern Echidnas are derived from a platypus-like ancestor, in which case the extensive olfactory specializations of the modern Echidnas would have developed relatively recently in monotreme evolution. In this study, the development of the constituent structures of the olfactory pathway was studied in sectioned platypus and Echidna embryos and post-hatchlings at the Museum fur Naturkunde, Berlin, Germany. The aim was to determine whether the olfactory structures follow a similar maturational path in the two monotremes during embryonic and early post-hatching ages or whether they show very different developmental paths from the outset. The findings indicate that anatomical differences in the central olfactory system between the short-beaked Echidna and the platypus begin to develop immediately before hatching, although details of differences in nasal cavity architecture emerge progressively during late post-hatching life. These findings are most consistent with the proposition that the two modern monotreme lineages have followed independent evolutionary paths from a less olfaction-specialized ancestor. The monotreme olfactory pathway does not appear to be sufficiently structurally mature at birth to allow olfaction-mediated behaviour, because central components of both the main and accessory olfactory system have not differentiated at the time of hatching.
Stewart C. Nicol - One of the best experts on this subject based on the ideXlab platform.
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Diet, feeding behaviour and Echidna beaks: a review of functional relationships within the tachyglossids
Australian Mammalogy, 2021Co-Authors: Stewart C. NicolAbstract:Echidnas are commonly known as ‘spiny ant-eaters’, but long-beaked Echidnas (Zaglossus spp.) do not eat ants, whereas short-beaked Echidnas (Tachyglossus aculeatus) eat other invertebrates as well as ants. The differences in skull morphology between short- and long-beaked Echidnas are related to the differences in their diets, and I tested the hypothesis that there would be differences in beak length of short-beaked Echidnas from populations with different diets. Published data on diet from Echidnas from different parts of Australia show that Echidnas from arid and semi-arid areas (subspecies acanthion) and Kangaroo Island (subspecies multiaculeatus) principally eat ants and termites, whereas the main dietary items of Echidnas from south-eastern Australia (subspecies aculeatus) and Tasmania (subspecies setosus) are ants and scarab larvae. Using museum specimens and photographs I measured skull dimensions on Echidnas from different parts of Australia: acanthion and multiaculeatus have narrower skulls and shorter beaks than aculeatus and setosus, with setosus being the only Australian subspecies where beak length exceeds cranium length. Australian short-beaked Echidnas fall into two groups: aculeatus and setosus from the wetter east and south-east, which eat ant and scarab larvae, and the arid and semi-arid zone acanthion and multiaculeatus, with shorter, narrower skulls, and which eat ants and termites.
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Energetics meets sexual conflict: The phenology of hibernation in Tasmanian Echidnas
Functional Ecology, 2019Co-Authors: Stewart C. Nicol, Gemma E. Morrow, Rachel L. HarrisAbstract:Echidnas are egg‐laying mammals found across Australia, and in Tasmania they hibernate, resulting in a most unusual mating system: males enter hibernation in late summer–early autumn and arouse in late autumn–early winter to mate, although females are still hibernating. Groups of males compete for matings and both males and females mate with multiple partners. Females that mate early return to hibernation even when pregnant, and males continue to mate with pregnant females. We asked to what extent can the bizarre combination of behavioural and physiological features that characterize reproduction of Tasmanian Echidnas be attributed to their phylogeny, and how much is a consequence of their ecology? To understand the interaction between energetics and the Echidna mating system in determining the timing of Echidna hibernation, we analysed data from an 18‐year study of a wild population of Tasmanian Echidnas (Tachyglossus aculeatus setosus) Males in best condition arouse earliest and seek out suitable females, and females that mate early in the mating season re‐enter hibernation while pregnant. Competition between males drives early mating and while mating with males in the best condition could be advantageous for females and their young, egg‐laying in winter is potentially disadvantageous, and post‐mating hibernation by females is a means of delaying hatching of young until environmental conditions are more favourable. This post‐mating hibernation by females is usually disrupted by males which mate with them although they are already pregnant. Comparisons with other Echidna populations suggest that a decreased activity period due to hibernation has not increased male–male competition. Similar competition between groups of males for access to females is seen in chlamyphorid armadillos, which occupy a similar ecological niche to Echidnas. A free Plain Language Summary can be found within the Supporting Information of this article.
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Latrines as Potential Communication Centres in Short-Beaked Echidnas
Chemical Signals in Vertebrates 14, 2019Co-Authors: Rachel L. Harris, Jenny Sprent, Stewart C. NicolAbstract:Localised defecation sites (‘latrines’) are an important method of intraspecific olfactory communication in mammals. As efficient, low-cost methods of exchanging information, latrines might be especially important for solitary or widely distributed species, or those with low metabolic rates or low-energy diets. Latrines can be difficult to find and closely monitor, but information on their spatial distribution and patterns of use can provide useful insights into their possible functions. We used geographic mapping and remote cameras to describe spatial, temporal and behavioural patterns in latrine use in a normally solitary monotreme, the short-beaked Echidna ( Tachyglossus aculeatus ; ‘Echidna’). We found 64 Echidna latrines, usually under logs in scrub habitat and in areas of intermediate (rather than low or high) areas of overlap between resident Echidna home ranges. Latrines were most often visited through July–November, and fresh scats were found between August and February. When visiting latrines, Echidnas showed olfactory behaviours such as scanning and nose-poking at the soil, suggesting latrines are not used purely for defecation and likely perform a role in communication. We suggest that latrines play a role in signalling habitat use, particularly among females, whereas males might use latrines to monitor the location and activities of potential mates and competitors.
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Spurs, sexual dimorphism and reproductive maturity in Tasmanian Echidnas (Tachyglossus aculeatus setosus)
Australian Mammalogy, 2019Co-Authors: Stewart C. Nicol, N A Andersen, Gemma E. Morrow, Rachel L. HarrisAbstract:We present data from an 18-year study of a wild population of Tasmanian Echidnas, which show that the presence of spurs in an adult are a reliable indicator of sex, and that there is a slight but significant sexual dimorphism in size, with a male to female mass ratio of 1.1. Minimum age at first breeding in the wild for Tasmanian Echidnas was 5 years, as has been found on Kangaroo Island, compared with 3 years in captive Echidnas. It is often assumed that although the Echidna is distributed throughout Australia, New Guinea and off-shore islands that all aspects of its basic biology are the same in all populations, but comparisons of our results with data from other populations suggest that there may be differences in size and sexual dimorphism.
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Interaction of hibernation and male reproductive function in wild Tasmanian Echidnas Tachyglossus aculeatus setosus
Journal of Mammalogy, 2016Co-Authors: Gemma E. Morrow, Susan M. Jones, Stewart C. NicolAbstract:The short-beaked Echidna Tachyglossus aculeatus is a seasonally breeding mammal with a near ubiquitous distribution throughout Australia. In Tasmania, breeding follows a period of deep hibernation, and males begin mating approximately 30 days after the termination of hibernation. The Echidna has exceptionally large testes, which may reach a maximum of 1% of body mass during the mating period. As involution of gonads is considered a prerequisite for entering hibernation and hibernation typically suppresses all reproductive function, this raises questions about the timing of testes recrudescence in the Tasmanian Echidna. We measured plasma testosterone concentrations and used ultrasonography to measure testicular and crural gland volume through the annual cycle in wild Tasmanian Echidnas. Testes were at their minimum size (0.06% of body mass) in December (early summer); testes recrudescence occurred prior to entry into hibernation when plasma testosterone concentrations were low; and testes were maintained at 75% of their maximum volume throughout the hibernation period. The crural glands, which are secondary reproductive structures in the Echidna, also exhibited an annual pattern of recrudescence and involution, with recrudescence occurring after males emerged from hibernation, when plasma testosterone was rising. We suggest that the unusual strategy of testes recrudescence occurring prior to hibernation in the Tasmanian Echidna is a consequence of extremely high competition between males.
Craig D. Hardman - One of the best experts on this subject based on the ideXlab platform.
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Brain and behaviour of living and extinct Echidnas.
Zoology (Jena Germany), 2014Co-Authors: Ken W.s. Ashwell, Craig D. Hardman, Anne M. MusserAbstract:Abstract The Tachyglossidae (long- and short-beaked Echidnas) are a family of monotremes, confined to Australia and New Guinea, that exhibit striking trigeminal, olfactory and cortical specialisations. Several species of long-beaked Echidna ( Zaglossus robusta , Zaglossus hacketti , Megalibgwilia ramsayi ) were part of the large-bodied (10 kg or more) fauna of Pleistocene Australasia, but only the diminutive (2–7 kg) Tachyglossus aculeatus is widespread today on the Australian mainland. We used high-resolution CT scanning and other osteological techniques to determine whether the remarkable neurological specialisations of modern Echidnas were also present in Pleistocene forms or have undergone modification as the Australian climate changed in the transition from the Pleistocene to the Holocene. All the living and extinct Echidnas studied have a similar pattern of cortical gyrification that suggests comparable functional topography to the modern short-beaked form. Osteological features related to olfactory, trigeminal, auditory and vestibular specialisation (e.g., foramina and cribriform plate area, osseous labyrinth topography) are also similar in living and extinct species. Our findings indicate that despite differences in diet, habitat and body size, the suite of neurological specialisations in the Tachyglossidae has been remarkably constant: encephalisation, sensory anatomy and specialisation (olfactory, trigeminal, auditory and vestibular), hypoglossal nerve size and cortical topography have all been stable neurological features of the group for at least 300,000 years.
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Distinct development of the trigeminal sensory nuclei in platypus and Echidna.
Brain behavior and evolution, 2012Co-Authors: Ken W.s. Ashwell, Craig D. HardmanAbstract:Both lineages of the modern monotremes have been reported to be capable of electroreception using the trigeminal pathways and it has been argued that electroreception arose in an aquatic platypus-like ancestor of both modern monotreme groups. On the other hand, the trigeminal sensory nuclear complex of the platypus is highly modified for processing tactile and electrosensory information from the bill, whereas the trigeminal sensory nuclear complex of the short-beaked Echidna (Tachyglossus aculeatus) is not particularly specialized. If the common ancestor for both platypus and Echidna were an electroreceptively and trigeminally specialized aquatic feeder, one would expect the early stages of development of the trigeminal sensory nuclei in both species to show evidence of structural specialization from the outset. To determine whether this is the case, we examined the development of the trigeminal sensory nuclei in the platypus and short-beaked Echidna using the Hill and Hubrecht embryological collections. We found that the highly specialized features of the platypus trigeminal sensory nuclei (i.e. the large size of the principal nucleus and oral part of the spinal trigeminal nuclear complex, and the presence of a dorsolateral parvicellular segment in the principal nucleus) appear around the time of hatching in the platypus, but are never seen at any stage in the Echidna. Our findings support the proposition that the modern Echidna and platypus are derived from a common ancestor with only minimal trigeminal specialization and that the peculiar anatomy of the trigeminal sensory nuclei in the modern platypus emerged in the ornithorhynchids after divergence from the tachyglossids.
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distinct development of peripheral trigeminal pathways in the platypus ornithorhynchus anatinus and short beaked Echidna tachyglossus aculeatus
Brain Behavior and Evolution, 2012Co-Authors: Ken W.s. Ashwell, Craig D. Hardman, Peter GiereAbstract:The extant monotremes (platypus and Echidnas) are believed to all be capable of electroreception in the trigeminal pathways, although they differ significantly in the number and distribution of electroreceptors. It has been argued by some authors that electroreception was first developed in an aquatic environment and that Echidnas are descended from a platypus-like ancestor that invaded an available terrestrial habitat. If this were the case, one would expect the developmental trajectories of the trigeminal pathways to be similar in the early stages of platypus and short-beaked Echidna development, with structural divergence occurring later. We examined the development of the peripheral trigeminal pathway from snout skin to trigeminal ganglion in sectioned material in the Hill and Hubrecht collections to test for similarities and differences between the two during the development from egg to adulthood. Each monotreme showed a characteristic and different pattern of distribution of developing epidermal sensory gland specializations (electroreceptor primordia) from the time of hatching. The cross-sectional areas of the trigeminal divisions and the volume of the trigeminal ganglion itself were also very different between the two species at embryonic ages, and remained consistently different throughout post-hatching development. Our findings indicate that the trigeminal pathways in the short-beaked Echidna and the platypus follow very different developmental trajectories from the earliest ages. These findings are more consistent with the notion that the platypus and Echidna have both diverged from an ancestor with rudimentary electroreception and/or trigeminal specialization, rather than the contention that the Echidna is derived from a platypus-like ancestor.
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Cyto- and chemoarchitecture of the sensory trigeminal nuclei of the Echidna, platypus and rat.
Journal of chemical neuroanatomy, 2005Co-Authors: Ken W.s. Ashwell, Craig D. Hardman, George PaxinosAbstract:We have examined the cyto- and chemoarchitecture of the trigeminal nuclei of two monotremes using Nissl staining, enzyme reactivity for cytochrome oxidase, immunoreactivity for calcium binding proteins and non-phosphorylated neurofilament (SMI-32 antibody) and lectin histochemistry (Griffonia simplicifolia isolectin B4). The principal trigeminal nucleus and the oralis and interpolaris spinal trigeminal nuclei were substantially larger in the platypus than in either the Echidna or rat, but the caudalis subnucleus was similar in size in both monotremes and the rat. The numerical density of Nissl stained neurons was higher in the principal, oralis and interpolaris nuclei of the platypus relative to the Echidna, but similar to that in the rat. Neuropil immunoreactivity for parvalbumin was particularly intense in the principal trigeminal, oralis and interpolaris subnuclei of the platypus, but the numerical density of parvalbumin immunoreactive neurons was not particularly high in these nuclei of the platypus. Neuropil immunoreactivity for calbindin and calretinin was relatively weak in both monotremes, although calretinin immunoreactive somata made up a large proportion of neurons in the principal, oralis and interpolaris subnuclei of the Echidna. Distribution of calretinin immunoreactivity and Griffonia simplicifolia B4 isolectin reactivity suggested that the caudalis subnucleus of the Echidna does not have a clearly defined gelatinosus region. Our findings indicate that the trigeminal nuclei of the Echidna do not appear to be highly specialized, but that the principal, oralis and interpolaris subnuclei of the platypus trigeminal complex are highly differentiated, presumably for processing of tactile and electrosensory information from the bill.
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Cyto- and chemoarchitecture of the amygdala of a monotreme, Tachyglossus aculeatus (the short-beaked Echidna).
Journal of chemical neuroanatomy, 2005Co-Authors: Ken W.s. Ashwell, Craig D. Hardman, George PaxinosAbstract:We have examined the cyto- and chemoarchitecture of the temporal and extended amygdala in the brain of a monotreme (the short-beaked Echidna Tachyglossus aculeatus) using Nissl and myelin staining, enzyme histochemistry for acetylcholine esterase and NADPH diaphorase, immunohistochemistry for calcium binding proteins (parvalbumin, calbindin and calretinin) and tyrosine hydroxylase. While the broad subdivisions of the eutherian temporal amygdala were present in the Echidna brain, there were some noticeable differences. No immunoreactivity for parvalbumin or calretinin for somata was found in the temporal amygdala of the Echidna. The nucleus of the lateral olfactory tract could not be definitively identified and the medial nucleus of amygdala appeared to be very small in the Echidna. Calbindin immunoreactive neurons were most frequently found in the ventrolateral part of the lateral nucleus, intraamygdaloid parts of the bed nucleus of the stria terminalis and the lateral part of the central nucleus. Neurons strongly reactive for NADPH diaphorase with filling of the dendritic tree were found mainly scattered through the cortical, central and lateral subnuclei, while neurons showing only somata reactivity for NADPH diaphorase were concentrated in the basomedial and basolateral subnuclei. Most of the components of the extended amygdala of eutherians could also be identified in the Echidna. Volumetric analysis indicated that the temporal amygdala in both the platypus and Echidna is small compared to the same structure in both insectivores and primates, with the central and medial components of the temporal amygdala being particularly small.
N A Andersen - One of the best experts on this subject based on the ideXlab platform.
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Spurs, sexual dimorphism and reproductive maturity in Tasmanian Echidnas (Tachyglossus aculeatus setosus)
Australian Mammalogy, 2019Co-Authors: Stewart C. Nicol, N A Andersen, Gemma E. Morrow, Rachel L. HarrisAbstract:We present data from an 18-year study of a wild population of Tasmanian Echidnas, which show that the presence of spurs in an adult are a reliable indicator of sex, and that there is a slight but significant sexual dimorphism in size, with a male to female mass ratio of 1.1. Minimum age at first breeding in the wild for Tasmanian Echidnas was 5 years, as has been found on Kangaroo Island, compared with 3 years in captive Echidnas. It is often assumed that although the Echidna is distributed throughout Australia, New Guinea and off-shore islands that all aspects of its basic biology are the same in all populations, but comparisons of our results with data from other populations suggest that there may be differences in size and sexual dimorphism.
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Spatial ecology of a ubiquitous Australian anteater, the short-beaked Echidna (Tachyglossus aculeatus)
Journal of Mammalogy, 2011Co-Authors: Stewart C. Nicol, Gemma E. Morrow, Cécile Vanpé, Jenny Sprent, N A AndersenAbstract:The only specialized ant-eating mammal in Australia and New Guinea is the egg-laying short-beaked Echidna (Tachyglossus aculeatus), and this single species occurs throughout Australia in a wide range of habitats. Despite the diversity of habitats and density and distribution of prey species, home-range sizes throughout Australia seem remarkably similar. We radiotracked Echidnas in a population in Tasmania over a 13-year period and calculated home-range sizes using the fixed kernel method and the minimum convex polygon method. No relationship was found between body mass and home-range size, and mean annual home-range size of males (90% kernels) was 107 ha 6 48 SD, twice that of females (48 6 28 ha). Male home ranges overlapped considerably and also overlapped with those of several females. The Echidna follows the pattern seen in many solitary eutherian mammals: both sexes are promiscuous, and males have larger home ranges than females. Echidnas show a high degree of home-range fidelity but can make rare excursions out of their normal area. Hibernating Echidnas move between shelters during their periodic arousals, resulting in home-range sizes similar to those of the active period. Consistent with their very low metabolic rate, Echidnas have home-range sizes considerably smaller than predicted for carnivorous or omnivorous mammals. Examination of data from other ant-eating mammals shows that as a group anteaters not only have smaller than predicted home ranges but they depart significantly from the normal relationship between home-range size and body mass.
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reproductive strategies of the short beaked Echidna a review with new data from a long term study on the tasmanian subspecies tachyglossus aculeatus setosus
Australian Journal of Zoology, 2009Co-Authors: Gemma E. Morrow, N A Andersen, S C NicolAbstract:The short-beaked Echidna is the most widely distributed endemic Australian mammal, and Echidnas from different geographic areas differ so much in appearance that they have been assigned to several subspecies. In this paper, we present data obtained from free-ranging Echidnas in southern Tasmania, and compare this with studies from other parts of Australia. In Tasmania mating occurs between early June and mid-September, and throughout Australia the normal breeding season lies within these limits. In Echidnas from the more easterly parts of Australia reproduction closely follows hibernation, with Tasmanian Echidnas showing a significant overlap between hibernation and reproduction. There is intense competition between males, and female Echidnas from Tasmania show multiple matings. There are significant differences between Echidnas from different areas of Australia in the use of nursery burrows and maternal care. One of the most dramatic differences is in duration of lactation: Echidnas from Kangaroo Island wean the young at 204–210 days, but in Tasmania weaning occurs at 139–152 days, even though the masses of the young at weaning are comparable.
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the life history of an egg laying mammal the Echidna tachyglossus aculeatus
Ecoscience, 2007Co-Authors: S C Nicol, N A AndersenAbstract:Echidnas have a low metabolic rate, and energy expenditure is reduced even further by the use of torpor and hibernation. Thus, Echidnas appear to lie at the slow extreme of the fast-slow continuum, and this is reflected in many aspects of Echidna life history: a long life, a long lactation period, and a single young that matures late. Reproductive activity occurs in mid-winter, shortly after arousal from hibernation. After a pregnancy of about 3 weeks the female lays a single egg into her pouch that hatches after 10-11 d. Initially, the young is incubated in the pouch. Later, it is left in the nursery burrow while the mother forages for ants, termites, and other invertebrates. Lactation lasts for 150-200 d, the duration differing significantly between geographic regions. Growth rates during late lactation are very high, and, when weaned, the young has reached about 40% of adult mass. The young loses mass before entering its first hibernation, which extends from early autumn to late spring. The young Echidna reaches adult mass after about 3-5 years. Keywords: Echidna, egg-laying, growth, hibernation, life history, metabolic rate, monotreme. Resume : Les echidnes ont un metabolisme lent et leurs depenses energetiques sont reduites d'autant plus par la torpeur et l'hibernation. Ainsi les echidnes semblent se situer a l'extremite lente du continuum rapide-lent et cela se reflete dans plusieurs aspects de leur histoire de vie : une longue duree de vie, une longue periode de lactation, un seul jeune qui atteint la maturite tardivement. L'activite reproductive arrive au milieu de l'hiver, peu de temps apres le reveil de l'hibernation. Apres une grossesse d'environ 3 semaines, la femelle pond dans sa poche un œuf unique qui eclot apres 10-11 jours. Au debut, le jeune est incube dans la poche, ensuite il est laisse dans un terrier pouponniere pendant que la mere cherche des araignees, des termites et d'autres invertebres. La lactation dure 150-200 jours, la duree variant de facon significative entre les regions. Les taux de croissance sont tres eleves a la fin de la lactation et lorsque le jeune est sevre, il a atteint environ 40 % de la masse adulte. Le jeune perd de la masse avant d'entrer dans sa premiere hibernation qui dure du debut de l'automne jusqu'a tard au printemps. Le jeune echidne atteint la masse adulte apres 3-5 ans. Mots-cles : croissance, echidne, hibernation, histoire de vie, metabolisme, monotreme, ponte d'œufs. Nomenclature: Griffiths, 1989.
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The life history of an egg-laying mammal, the Echidna
2007Co-Authors: Stewart C. Nicol, N A AndersenAbstract:Echidnas have a low metabolic rate, and energy expenditure is reduced even further by the use of torpor and hibernation. Thus Echidnas appear to lie at the slow extreme of the fast-slow continuum, and this is reflected in many aspects of Echidna life history: a long life, a long lactation period, and a single young which matures late. Reproductive activity occurs in mid-winter, shortly after arousal from hibernation. After a pregnancy of about 3 weeks the female lays a single egg into her pouch, which hatches after 10 – 11 days. Initially the young is incubated in the pouch before being left in the nursery burrow while the mother forages for ants, termites and other invertebrates. Lactation lasts for 150 - 200 days, the duration differing significantly between geographic regions. Growth rates during late lactation are very high, and, when weaned, the young has reached about 40% of adult mass. The young loses mass before entering its first hibernation, which extends from early autumn to late spring. The young Echidna reaches adult mass after about 3 - 5 years.
Darren G. Quin - One of the best experts on this subject based on the ideXlab platform.
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Platypus and Echidnas
Pacific Conservation Biology, 1997Co-Authors: Darren G. QuinAbstract:Platypus and Echidnas presents the proceedings of a conference held at the University of New South Wales in July 1991. Platypus and Echidnas incorporates an extensive information source obtained from studies undertaken since the first symposium on "Monotreme Biology" in 1978, while highlighting deficiencies in our knowledge, and subsequently suggests further avenues for research. The theme of evolution re-occurs throughout the publication and the studies demonstrate how patterns of mammalian phylogeny may be derived from various sources including palaeontology, gene mapping, DNA hybridization, reproductive physiology and endocrinology. Interest in this publication will extend to: (i) scholars of phylogeny and evolution especially part 1); (ii) comparative physiologist, physiological ecologists and anatomists (parts 1, 3, 4 and 5); (iii) ecologists and sacio-ecologists (parts 3, 5 and 6); (iv) natural historians; (v) keepers of captive wildlife colonies (parts 3 and 6); (vi) wildlife veterinary surgeons (part 6); and (vii) wildlife managers (especially part 6). The book deals primarily with the short-beaked Echidna Tachyglossus aculeatus and the platypus Ornithorhynchus anatinus, for which most information is available.
