Tenrec Ecaudatus Research Articles

Common tenrecs (Tenrec ecaudatus) reduce oxygen consumption in hypoxia and in hypercapnia without concordant changes to body temperature or heart rate.

Common tenrecs (Tenrec ecaudatus) are fossorial mammals that use burrows during both active and hibernating seasons in Madagascar and its neighboring islands. Prevailing thought was that tenrecs hibernate for 8-9months individually, but 13 tenrecs were removed from the same sealed burrow 1m deep from the surface. Such group hibernation in sealed burrows presumably creates a hypoxic and/or hypercapnic environment and suggests that this placental mammal may have an increased tolerance to hypoxia and hypercapnia. Higher tolerances to hypoxia and hypercapnia have been documented for other mammals capable of hibernation and to determine if this is the case for tenrecs, we exposed them to acute hypoxia (4h of 16 or 7% O2), progressive hypoxia (2h of 16, 10 and 4% O2), or progressive hypercapnia (2h of 2, 5 and 10% CO2) at cold (16°C) or warm (28°C) ambient temperatures (Ta). Oxygen equilibrium curves were also constructed on the whole blood of tenrecs at 10, 25, and 37°C to determine if hemoglobin (Hb)-O2 affinity contributes to hypoxia tolerance. In animals held at 16°C, normoxic and normocapnic levels of oxygen consumption rate ( ), body temperature (Tb), and heart rate (HR) were highly variable between individuals. This inter-individual variation was greatly reduced in animals held at 28°C for oxygen consumption rate and body temperature. Both hypoxia (acute and progressive) and progressive hypercapnia led to decreases in as well as the variation in between animals held at 16°C. The fall in oxygen consumption rate in 7% O2 independent of changes in body temperature in tenrecs held at 16°C is unique and not consistent with the typical hypoxic metabolic response seen in other hibernating species that depends on concomitant falls in Tb. In animals held at 28°C, exposure to O2 levels as low as 4% and CO2 levels as high as 10% had no significant effect on , HR, or Tb, indicative of high tolerance to both hypoxia and hypercapnia. High variation in heart rate remained between individuals in all gas compositions and at all temperatures. Tenrec Hb-O2 affinity was similar to other homeothermic placental mammals and likely does not contribute to the increased hypoxia tolerance. Ultimately, our results suggest changes in Ta dictate physiological responses to hypoxia or hypercapnia in tenrecs, responses more characteristic of reptiles than of most placental mammals. Given that numerous anatomical and physiological characteristics of tenrecs suggest that they may be representative of an ancestral placental mammal, our findings suggest the typical hypoxic metabolic response evolved later in mammalian evolution.

Cell type and cell signaling innovations underlying mammalian pregnancy.

The fetal-maternal interface is one of the most intense loci of cell-cell signaling in the human body. Invasion of cells from the fetal placenta into the uterus, and the corresponding transformation of maternal tissues called decidualization, first evolved in the stem lineage of eutherian mammals( 1 , 2 ). Single-cell studies of the human fetal-maternal interface have provided new insight into the cell type diversity and cell-cell interactions governing this chimeric organ( 3-5 ). However, the fetal-maternal interface is also one of the most rapidly evolving, and hence most diverse, characters among mammals( 6 ), and an evolutionary analysis is missing. Here, we present and compare single-cell data from the fetal-maternal interface of species bracketing key events in mammal phylogeny: a marsupial (opossum, Monodelphis domestica ), the afrotherian Tenrec ecaudatus, and four Euarchontoglires - guinea pig and mouse (Rodentia) together with recent macaque and human data (primates) ( 4 , 5 , 7 ). We infer cell type homologies, identify a gene-expression signature of eutherian invasive trophoblast conserved over 99 million years, and discover a predecidual cell in the tenrec which suggests stepwise evolution of the decidual stromal cell. We reconstruct ancestral cell signaling networks, revealing the integration of fetal cell types into the interface. Finally, we test two long-standing theoretical predictions, the disambiguation hypothesis( 8 ) and escalation hypothesis( 9 ), at transcriptome-wide scale, finding divergence between fetal and maternal signaling repertoires but arms race dynamics restricted to a small subset of ligand-receptor pairs. In so doing, we trace the co-evolutionary history of cell types and their signaling across mammalian viviparity.

The use of micro-computed tomography to investigate splenic control of resting oxygen consumption in Tenrec ecaudatus

The canonical functions of the spleen e.g. immune function, blood filtering, and iron recycling overshadow its known role as a blood storage organ in mammals. Boreoeutherians or modern mammals, such as race horses and dogs, experience splenic contractions during exercise where a 30-40% increase in red blood cell availability is associated with an increase in oxygen consumption. Early data (pre-1960) suggest that splenic sequestration may be used in hibernators. Tenrec ecaudatus are basoendothermic mammals that possess numerous ancestral features such as a cloaca. We posit that tenrecs may provide evolutionary insight into the ancestral function of the spleen. Tenrecs may experience as much as a 25-fold variation in resting oxygen consumption as well as a 14-fold variation in spleen size. We contend that sequestration of red blood cells to the spleen in tenrecs controls oxygen consumption. Here, we present data that directly tests the association of spleen size and oxygen consumption using micro-computed tomography. We contend the boreoeutherian functions of the spleen may be a derived condition afforded by a heightened level of endothermy/homeothermy and its associated higher level of homeostasis. National Science Foundation, Department of Education. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Life in the Slow Lane: The Rate of Protein Synthesis Is Slower in the Protoendothermic Tenrec than the Boreoeutherian Golden-Mantled Ground Squirrel

In order to address mechanisms of how hibernating mammals depress protein synthesis during torpor, we developed primary cell cultures from golden-mantled ground squirrels (Spermophilus [Callospermophilus] lateralis) and tenrecs (Tenrec ecaudatus). During torpor in squirrels, there is an acute uncoupling of translational initiation and elongation at body temperature (Tb) = 18°C as animals enter torpor. As a result, there are robust changes to the polysome profile of squirrels depending on state. Protein synthesis is depressed to 0.23 to 0.5% of active rates during torpor. In the bizarre, Afrotherian Tenrec ecaudatus, metabolism and Tb are remarkably plastic. Tenrecs may be fully active with a Tb of 12 °C or hibernating at a Tb of 28 °C. Moreover, oxygen consumption rates may vary 25 fold in active tenrecs. With this high variability in Tb, one might expect that these tenrecs might not be able to use Tb to control protein synthesis. Liver polysome profiles were confusing- there were no real changes between states or temperature. Rather, all tenrecs had a rather modest polysome profile with little heavy material typical of very active protein synthesis. To address this, we developed liver (do not grow well) and kidney cell (grow very well) cultures from ground squirrels and tenrecs. Our results indicate that the translation rate in tenrec primary cells is ~30 % of the translation rate in golden-mantled ground squirrel (p < 0.05). We interpret these results as tenrecs living ‘Life in the Slow Lane.’ By experiencing these low rates of a process critical to homeostasis, we contend tenrecs are avoiding rapid changes as a consequence of their rapid changes in Tb or metabolism. In effect, ‘driving slowly’ allows a tenrec to avoid major accidents which would imperil the animal. Perhaps not surprisingly, tenrec litters are enormous with as many as 32 confirmed young in a single litter. This research was supported by the Translational Research Institute for Space Health (TRISH). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Extraordinary creatures: Tenrec ecaudatus (the common tenrec)

Tenrec ecaudatus (the common tenrec) is a small mammal (250 g–2 kg) that is native to Madagascar and has been introduced to other islands in the Indian Ocean. Tenrecs dine on insects, small reptiles, amphibians and mammals in the wild, but also consume fruit and vegetation and are thought to hibernate for up to 8 months. However, unlike other hibernators, which periodically arouse from torpor during hibernation, tenrecs do not and are notoriously difficult to keep in captivity. Frank van Breukelen, custodian of the only known colony of captive tenrecs, tells Journal of Experimental Biology about these extraordinary creatures and the challenges that he has faced learning about their unconventional physiology and how to care for them.

Tenrecs deal with poor air quality like reptiles

Dealing with dangerously high CO2 levels is a regular part of life for burrowing creatures. ‘Most animals that are able to tolerate such environments reduce their metabolic rate to re-balance their energy demands’, says Matthew Pamenter from the University of Ottawa, Canada. So, when he heard Frank van Breukelen of the University of Nevada, USA, talk about his burrowing tenrec (Tenrec ecaudatus) colony at a conference in 2019, he realised that the animals might also experience dangerous CO2 concentrations – up to 13.5%, compared with 0.04% in the atmosphere – when hibernating with burrow-mates for 8–9 months. Yet tenrecs are not regular mammals. They can remain active even when their body temperature plummets to 12°C; so how do they cope with the toxic air in their hibernation burrows?Pamenter contacted van Breukelen to suggest a collaboration, and in March 2020, Maiah Devereaux (University of Ottawa) joined Claudia Silva Rubio and van Breukelen at the University of Nevada to find out how tenrecs deal with excessive CO2 and low O2. ‘Our tenrecs are handled very frequently and so they are very docile. To be honest, they are kind of lazy!’ chuckles van Breukelen, who recalls that the animals were content to hang out in a respirometry chamber while Devereaux and Silva Rubio measured the tenrecs’ breath rate and O2 consumption to calculate their metabolic rate. The duo then modified the air mixture the tenrecs were breathing – first reducing the O2 content from 21% to 9% and 4%, before boosting the CO2 levels from 0% to 5% and 10% – at 28°C and 16°C, to find out how the mammals responded. ‘Trying to maintain a stable [gas] flow rate required some troubleshooting’, says van Breukelen.Even when the tenrecs were breathing normal air in the cooler conditions, the active animals’ metabolisms responded unconventionally. Some barely breathed at all – only consuming 2 ml O2 min−1 kg−1 – while others inhaled a colossal amount (23 ml O2 min−1 kg−1) relative to the warmer tenrecs, which only inhaled 12 ml O2 min−1 kg−1 at the most. Raising the CO2 levels in the air didn't affect the range of the cold tenrec's metabolic rates; however, when the team reduced the animals’ O2 supply, the chilly animals no longer had the wide range of metabolic rates they had when breathing normal air.The air temperature also had a major impact on the way the tenrecs breathed when their air was contaminated with CO2. The warmer animals began hyperventilating when the CO2 levels increased, in contrast to the cooler tenrecs, which were more like other burrowing mammals and did not hyperventilate.In short, the tenrecs’ breathing and metabolism were more affected by the environmental temperature than the build-up of toxic CO2 and quantity of O2 available. In addition, the animals in the colder conditions allowed their body temperatures to drift, with some cooling to 20°C while others remained at 32°C regardless of the air quality; all of the tenrecs in 28°C air maintained a warm body temperature (∼32°C) despite the air conditions. The physiological responses of the tenrecs were more like those of cold-blooded reptiles than those of warm-blooded burrowing mammals, probably because they don't have to maintain a high body temperature to survive. van Breukelen exclaims, ‘Many of the things that tenrecs do result in me saying, “How the heck do they do this?”’, and he is excited to find out how the animals cope with poor air quality when breathing as little as once every 45 min while hibernating.

Physiological responses to hypoxia are constrained by environmental temperature in heterothermic tenrecs.

Malagasy tenrecs are placental hibernating mammals that seal the entrances to their burrows and hibernate either singly or in groups for 8-9 months, which is likely to create a hypoxic and hypercapnic burrow environment. Therefore, we hypothesized that tenrecs are tolerant to environmental hypoxia and hypercapnia. Many hypoxia- and hypercapnia-tolerant fossorial mammals respond to hypoxia by decreasing metabolic rate and thermogenesis, and have blunted ventilatory responses to both environmental hypoxia and hypercapnia. However, tenrecs exhibit extreme metabolic and thermoregulatory plasticity, which exceeds that of most heterothermic mammals and approaches that of ectothermic reptiles. Thus, we predicted that tenrecs would have abnormal physiological responses to hypoxia and hypercapnia relative to other fossorial mammals. To test this, we exposed common tenrecs (Tenrec ecaudatus) to moderate and severe hypoxia (9 and 4% O2) or hypercapnia (5 and 10% CO2) in either 28 or 16°C while non-invasively measuring metabolic rate, thermogenesis and ventilation. We found that tenrecs exhibit robust metabolic decreases in both hypoxia and hypercapnia. Furthermore, tenrecs have blunted ventilatory responses to both hypoxia and hypercapnia, and these responses are highly temperature sensitive such that they are reduced or absent in 16°C. Thermoregulation was highly variable in 16°C but constrained in 28°C across all treatment conditions and was not impacted by hypoxia or hypercapnia, unlike in other heterothermic mammals. Taken together, our results indicate that physiological responses to hypoxia and hypercapnia in tenrecs are highly dependent on environmental temperature and differ from those of other mammalian heterotherms.

Co-Radiation of Leptospira and Tenrecidae (Afrotheria) on Madagascar.

Leptospirosis is a bacterial zoonosis caused by pathogenic Leptospira that are maintained in the kidney lumen of infected animals acting as reservoirs and contaminating the environment via infected urine. The investigation of leptospirosis through a One Health framework has been stimulated by notable genetic diversity of pathogenic Leptospira combined with a high infection prevalence in certain animal reservoirs. Studies of Madagascar’s native mammal fauna have revealed a diversity of Leptospira with high levels of host-specificity. Native rodents, tenrecids, and bats shelter several distinct lineages and species of Leptospira, some of which have also been detected in acute human cases. Specifically, L. mayottensis, first discovered in humans on Mayotte, an island neighboring Madagascar, was subsequently identified in a few species of tenrecids on the latter island, which comprise an endemic family of small mammals. Distinct L. mayottensis lineages were identified in shrew tenrecs (Microgale cowani and Nesogale dobsoni) on Madagascar, and later in an introduced population of spiny tenrecs (Tenrec ecaudatus) on Mayotte. These findings suggest that L. mayottensis (i) has co-radiated with tenrecids on Madagascar, and (ii) has recently emerged in human populations on Mayotte following the introduction of T. ecaudatus from Madagascar. Hitherto, L. mayottensis has not been detected in spiny tenrecs on Madagascar. In the present study, we broaden the investigation of Malagasy tenrecids and test the emergence of L. mayottensis in humans as a result of the introduction of T. ecaudatus on Mayotte. We screened by PCR 55 tenrecid samples from Madagascar, including kidney tissues from 24 individual T. ecaudatus. We describe the presence of L. mayottensis in Malagasy T. ecaudatus in agreement with the aforementioned hypothesis, as well as in M. thomasi, a tenrecid species that has not been explored thus far for Leptospira carriage.

Tenrecs: freaks we can all learn from

Tenrecs, hedgehog-like mammals more closely related to elephants than hedgehogs, are freaks of nature when it comes to body temperature regulation. Most mammals that vary their body temperature (heterotherms) are not active at low body temperatures and instead become torpid – a state where their metabolic rate is reduced and they either become immobile, as in an extreme form of sleep, or very lethargic. Tenrecs, on the other hand, can remain active with body temperatures as low as ∼14°C and they can become torpid at relatively warm ambient and body temperatures of 28°C. A group of researchers, led by Frank van Breukelen at the University of Nevada, USA, and Jane Khudyakov at the University of the Pacific, USA, sought to further understand the underlying physiology behind the common tenrec's (Tenrec ecaudatus) extraordinary abilities by looking at the proteins expressed in the animal's liver.van Breukelen and his colleagues kept the tenrecs either at a cool (12°C) or warm (28°C) temperature in their captive colony at the University of Nevada Las Vegas, USA. Then, the researchers collected liver samples from three tenrecs that remained active in the warm conditions with a body temperature of 33.5°C and three that had slipped into torpor with body temperatures ∼27.7°C. Of the tenrecs housed at the cool temperature, the researchers took samples from three tenrecs that had become torpid with body temperatures of 12.8°C, three active tenrecs with cool body temperatures (14.5°C) and three active tenrecs with warm 30.2°C body temperatures. In this way, the researchers were able to not only compare active and torpid animals, but also body temperature with activity state. This experimental design is almost impossible to do with most other hibernators, as most mammals are not able to be active at such low body temperatures or become torpid at such high body temperatures.Of the 768 liver proteins that the team could identify, 51% were different between the torpid and active animals, which is almost unheard of; hibernating ground squirrels change the expression of only 15.5% of their proteins when they switch off for their long winter slumber. These differences in protein abundance were mostly connected to protein turnover, coordinating the processes that build proteins (anabolism) and those that break them down (catabolism). Additionally, they found nine proteins that were present more in the chillier temperatures, which may identify part of the liver's response to cold. 72.2% of the proteins that were upregulated in the cold tenrecs that remained active, compared with the warm active animals, were also upregulated in the tenrecs that had slipped into torpor at 28°C. This suggests that being at a cooler environmental temperature and being active at a low body temperature may hinder the animals’ ability to maintain a stable set of proteins. Overall, many of the 768 proteins identified overlapped with proteins found in other hibernating species, suggesting that even across distantly related species, the core metabolic pathways dealing with torpor are conserved.By researching the common tenrec – one of the most heterothermic mammal species, which retains many of the same physical characteristics as the first mammal – we can get a better understanding of how the ability to maintain a stable body temperature, homeothermy, may have evolved from heterothermy. van Breukelen and his colleagues predict that the evolution of homeothermy likely came about from the better coordination of protein destruction and production, resulting in a more balanced set of proteins matched to the thermal sensitivities of metabolic pathways.

Evaluation of tenrec population viability and potential sustainable management under hunting pressure in northeastern Madagascar

AbstractAcross the Global South, wildlife is an important source of nutrition and income, particularly for rural communities. While wildlife consumption provides a valuable source of nutrition, high levels of hunting can endanger wildlife species. In the Makira region of north‐eastern Madagascar, human health is threatened by food insecurity and malnutrition, and spiny tenrecs are a crucial source of subsistence bushmeat with 91% of households consuming tenrecs at least once per year. Moreover, Makira’s human populations are increasing, resulting in forest decline and degradation. In order to inform conservation and public health efforts, we investigated the influence of hunting, habitat loss and forest degradation on spiny tenrec population dynamics in the Makira region. We collected data on tenrec population densities as well as hunting and consumption by humans in 51 communities. We used these data to conduct a population viability analysis for the two most commonly hunted spiny tenrecs (Tenrec ecaudatus and Setifer setosus). We found that current harvest rates for these species are generally sustainable in the Makira region, largely due to tenrecs’ extraordinary fecundity. However, even assuming no change in current hunting rates, tenrec populations could become threatened if fecundity were to decline or background mortality to increase, both possible scenarios under future trajectories of habitat loss and degradation. We find that any future increase in hunting‐induced mortality rates for tenrecs are similarly unsustainable – and likely to occur as human populations expand and hunting areas decline. We conclude that there is a vanishing window of opportunity to sustainably manage tenrec hunting in northeastern Madagascar in order to avoid negative conservation and human health outcomes.

Geographical distribution and relative risk of Anjozorobe virus (Thailand orthohantavirus) infection in black rats (Rattus rattus) in Madagascar

BackgroundHantavirus infection is a zoonotic disease that is associated with hemorrhagic fever with renal syndrome and cardiopulmonary syndrome in human. Anjozorobe virus, a representative virus of Thailand orthohantavirus (THAIV), was recently discovered from rodents in Anjozorobe-Angavo forest in Madagascar. To assess the circulation of hantavirus at the national level, we carried out a survey of small terrestrial mammals from representative regions of the island and identified environmental factors associated with hantavirus infection. As we were ultimately interested in the potential for human exposure, we focused our research in the peridomestic area.MethodsSampling was achieved in twenty districts of Madagascar, with a rural and urban zone in each district. Animals were trapped from a range of habitats and examined for hantavirus RNA by nested RT-PCR. We also investigated the relationship between hantavirus infection probability in rats and possible risk factors by using Generalized Linear Mixed Models.ResultsOverall, 1242 specimens from seven species were collected (Rattus rattus, Rattus norvegicus, Mus musculus, Suncus murinus, Setifer setosus, Tenrec ecaudatus, Hemicentetes semispinosus). Overall, 12.4% (111/897) of Rattus rattus and 1.6% (2/125) of Mus musculus were tested positive for THAIV. Rats captured within houses were less likely to be infected than rats captured in other habitats, whilst rats from sites characterized by high precipitation and relatively low seasonality were more likely to be infected than those from other areas. Older animals were more likely to be infected, with infection probability showing a strong increase with weight.ConclusionsWe report widespread distribution of THAIV in the peridomestic rats of Madagascar, with highest prevalence for those living in humid areas. Although the potential risk of infection to human may also be widespread, our results provide a first indication of specific zone with high transmission. Gathered data will be helpful to implement policies for control and prevention of human risk infection.

The Status Of Protein Translation In A Metabolically Flexible Mammal, The Common Tenrec, Tenrec ecaudatus

Common tenrecs, Tenrec ecaudatus, are small tropical hibernating mammals endemic to Madagascar. Tenrecs possess many phenotypic features associated to ancestral mammals, suggesting they may act as a model of an ancestral form of hibernation. Common tenrecs are able to hibernate at ambient temperatures ranging from 12 to 28 °C and do not undergo brief periodic returns to euthermy during the hibernation season, a shared feature among all other known hibernators. Tenrecs display extreme metabolic flexibility. For instance, they can spontaneously enter torpor during the active season, termed facultative torpor (FT). During both hibernation and FT, oxygen consumption rates have been observed to be 1–14% of active rates depending on ambient temperatures. Protein metabolism may account for 30% or more of standard oxygen consumption rates for most animals. Polysome profiles were used to determine the status of translation in tenrecs as a function of core body temperature (Tb) and activity state. Our findings will provide mechanistic data that will be used to elucidate how common tenrecs are able to regulate metabolic flux exclusive of Tb.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Hemoglobin In An Ancestral Hibernator, The Common Tenrec, Tenrec ecaudatus

Common tenrecs, Tenrec ecaudatus, are medium‐sized mammalian tropical hibernators endemic to Madagascar. Tenrecs are capable of effectively hibernating at temperatures between 12 and 28°C and do not undergo periodic arousals during hibernation, a feature common to all other known hibernators. Interestingly, these tenrecs can also experience spontaneous bouts of torpor during the active season known as facultative torpor (FT). During hibernation and FT, oxygen consumption rates are 1.1–14% of active rates depending on ambient temperature. We have observed marked variation in hematocrit (between 15 and 50%). We asked what happens to hemoglobin concentration and type across the annual cycle and state. A colorimetric assay was performed for hemoglobin concentration in whole blood. Isoelectric focusing was used to assay for changes in hemoglobin type (e.g. fetal vs adult types) across the physiological states. These data will serve as an initial step in helping to determine how tenrecs are able to achieve low metabolic rates without concomitant decreases in body temperature.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Extreme physiological plasticity in a hibernating basoendothermic mammal, Tenrec ecaudatus.

Physiological plasticity allows organisms to respond to diverse conditions. However, can being too plastic actually be detrimental? Malagasy common tenrecs, Tenrec ecaudatus, have many plesiomorphic traits and may represent a basal placental mammal. We established a laboratory population of T. ecaudatus and found extreme plasticity in thermoregulation and metabolism, a novel hibernation form, variable annual timing, and remarkable growth and reproductive biology. For instance, tenrec body temperature (Tb) may approximate ambient temperature to as low as 12°C even when tenrecs are fully active. Conversely, tenrecs can hibernate with Tb of 28°C. During the active season, oxygen consumption may vary 25-fold with little or no change in Tb During the austral winter, tenrecs are consistently torpid but the depth of torpor may vary. A righting assay revealed that Tb contributes to but does not dictate activity status. Homeostatic processes are not always linked, e.g. a hibernating tenrec experienced a ∼34% decrease in heart rate while maintaining constant body temperature and oxygen consumption rates. Tenrec growth rates vary but young may grow ∼40-fold in the 5 weeks until weaning and may possess indeterminate growth as adults. Despite all of this profound plasticity, tenrecs are surprisingly intolerant of extremes in ambient temperature (<8 or >34°C). We contend that while plasticity may confer numerous energetic advantages in consistently moderate environments, environmental extremes may have limited the success and distribution of plastic basal mammals.

Landscape trends in small mammal occupancy in the Makira–Masoala protected areas, northeastern Madagascar

Madagascar’s native small mammals (Tenrecidae and Nesomyinae) are understudied. To help fill these knowledge gaps, we analyzed 1,575 detections of small mammals obtained during camera-trap surveys at 7 sites in northeastern Madagascar (2008–2011) using single-season occupancy analyses in program PRESENCE. We estimated landscape occupancy and detection probabilities of tufted-tailed rats ( Eliurus spp.), red forest rats ( Nesomys spp.), greater hedgehog tenrecs ( Setifer setosus ), and common tenrecs ( Tenrec ecaudatus ) and examined how these parameters responded to habitat characteristics, habitat degradation, and the trap success of native and exotic carnivorans. Only Nesomys showed a marked difference in mean occupancy between intact (ψ = 0.71 ± SE 0.06), intermediately degraded (ψ = 0.23 ± SE 0.05), and degraded (ψ = 0.34 ± SE 0.06) forest sites. Only Nesomys and Setifer occupancy was strongly influenced by habitat characteristics; Nesomys occupancy was positively related to distance away from forest edge (β = 1.39 ± SE 0.27) and percent rainforest cover (β = 1.89 ± SE 0.39), and Setifer occupancy negatively related to average canopy height (β = −0.52 ± SE 0.25). We found trap success of exotic carnivorans had little influence on small mammal occupancy and detection probabilities (with the exception of Eliurus ). We suggest that camera traps are a valid method for studying aspects of small mammal ecology, but caution researchers to consider characteristics of camera traps (e.g., trigger speed) to increase potential inference.

Identification of Tenrec ecaudatus, a Wild Mammal Introduced to Mayotte Island, as a Reservoir of the Newly Identified Human Pathogenic Leptospira mayottensis.

Leptospirosis is a bacterial zoonosis of major concern on tropical islands. Human populations on western Indian Ocean islands are strongly affected by the disease although each archipelago shows contrasting epidemiology. For instance, Mayotte, part of the Comoros Archipelago, differs from the other neighbouring islands by a high diversity of Leptospira species infecting humans that includes Leptospira mayottensis, a species thought to be unique to this island. Using bacterial culture, molecular detection and typing, the present study explored the wild and domestic local mammalian fauna for renal carriage of leptospires and addressed the genetic relationships of the infecting strains with local isolates obtained from acute human cases and with Leptospira strains hosted by mammal species endemic to nearby Madagascar. Tenrec (Tenrec ecaudatus, Family Tenrecidae), a terrestrial mammal introduced from Madagascar, is identified as a reservoir of L. mayottensis. All isolated L. mayottensis sequence types form a monophyletic clade that includes Leptospira strains infecting humans and tenrecs on Mayotte, as well as two other Malagasy endemic tenrecid species of the genus Microgale. The lower diversity of L. mayottensis in tenrecs from Mayotte, compared to that occurring in Madagascar, suggests that L. mayottensis has indeed a Malagasy origin. This study also showed that introduced rats (Rattus rattus) and dogs are probably the main reservoirs of Leptospira borgpetersenii and Leptospira kirschneri, both bacteria being prevalent in local clinical cases. Data emphasize the epidemiological link between the two neighbouring islands and the role of introduced small mammals in shaping the local epidemiology of leptospirosis.

Torpor in Tenrecs, a Basal Protoendothermic Mammal

Thirty of the 33 described tenrec species are endemic to Madagascar. These basal mammals possess features such as a cloaca and variable body temperature (Tb). We measured the energetics of common tenrecs, Tenrec ecaudatus, during the hibernation season. Tenrecs are capable of variable arousal from torpor but do not perform the predictable interbout arousals characteristic of all other known small hibernators. At lower ambient temperatures, ventilation may be punctuated with periods of 30 min or more between breaths. We found discordant changes to oxygen consumption (VO2), heart rate (HR), and Tb e.g. a spontaneous 23% decrease in VO2 was accompanied by an 47% decrease in HR and no change in Tb. Marked changes in Tb could occur with little change to VO2. We hypothesize that hibernation in tenrecs may represent a plesiomorphic form that is manifested by poor coordination of key homeostatic processes.

Mammal survival at the Cretaceous-Palaeogene boundary: metabolic homeostasis in prolonged tropical hibernation in tenrecs.

Free-ranging common tenrecs, Tenrec ecaudatus, from sub-tropical Madagascar, displayed long-term (nine months) hibernation which lacked any evidence of periodic interbout arousals (IBAs). IBAs are the dominant feature of the mammalian hibernation phenotype and are thought to periodically restore long-term ischaemia damage and/or metabolic imbalances (depletions and accumulations). However, the lack of IBAs in tenrecs suggests no such pathology at hibernation Tbs > 22°C. The long period of tropical hibernation that we report might explain how the ancestral placental mammal survived the global devastation that drove the dinosaurs and many other vertebrates to extinction at the Cretaceous-Palaeogene boundary following a meteorite impact. The genetics and biochemistry of IBAs are of immense interest to biomedical researchers and space exploration scientists, in the latter case, those envisioning a hibernating state in astronauts for deep space travel. Unravelling the physiological thresholds and temperature dependence of IBAs will provide new impetus to these research quests.

Development and embryonic staging in non‐model organisms: the case of an afrotherian mammal

Studies of evolutionary developmental biology commonly use 'model organisms' such as fruit flies or mice, and questions are often functional or epigenetic. Phylogenetic investigations, in contrast, typically use species that are less common and mostly deal with broad scale analyses in the tree of life. However, important evolutionary transformations have taken place at all taxonomic levels, resulting in such diverse forms as elephants and shrews. To understand the mechanisms underlying morphological diversification, broader sampling and comparative approaches are paramount. Using a simple, standardized protocol, we describe for the first time the development of soft tissues and some parts of the skeleton, using μCT-imaging of developmental series of Echinops telfairi and Tenrec ecaudatus, two tenrecid afrotherian mammals. The developmental timing of soft tissue and skeletal characters described for the tenrecids is briefly compared with that of other mammals, including mouse, echidna, and the opossum. We found relatively few heterochronic differences in development in the armadillo vs. tenrec, consistent with a close relationship of Xenarthra and Afrotheria. Ossification in T.ecaudatus continues well into the second half of overall gestation, resembling the pattern seen in other small mammals and differing markedly from the advanced state of ossification evident early in the gestation of elephants, sheep, and humans.

Two New Eimerians (Apicomplexa) from Insectivorous Mammals in Madagascar

Fecal samples from 126 insectivorous mammals in Madagascar were collected between spring 1999 and fall 2001. In the Afrosoricida, 21 species in 5 genera were sampled, including 17 species of Microgale (31/96, 32% infected), Hemicentetes semispinosus (1/2, 50%), Oryzorictes hova (1/5, 20%), Setifer setosus (8/13, 61.5%), and Tenrec ecaudatus (5/8, 62.5%); in the Soricomorpha, only Suncus murinus was examined and 1/2 (50%) were infected. Two morphotypes of eimeriid oocysts, representing 2 presumptive new species, were found in 47 (37%) infected animals; only 2 afrosoricid hosts (2% of all hosts, 4% of infected hosts) had both oocyst morphotypes. Sporulated oocysts of the first morphotype, Eimeria tenrececaudata n. sp., are subspheroidal, 18.8 × 17.4 (17-22 × 15-20), with a length∶width ratio (L/W) of 1.1 (1.0-1.2); they lack a micropyle but may contain 0-2 polar granules and a single, small round oocyst residuum, 3 × 2.3. Sporocysts are lemon-shaped, 9.9 × 6.6 (9-11 × 5-8), with a L/W of 1.5 (1.2-2.0); they have a prominent, slightly flattened Stieda body and a substieda body but lack a parastieda body. The sporocyst residuum consists of only a few granules between the sporozoites, which are sausage-shaped and have a large posterior refractile body. Oocysts of the second morphotype, Eimeria setifersetosa n. sp. are spheroidal to subspheroidal, 30.1 × 28.6 (27-34 × 25-34), with a L/W of 1.1 (1.0-1.2); they lack both micropyle and oocyst residuum, but 1-2 polar granules are usually present. Sporocysts are subspheroidal to broadly ellipsoidal, 9.6 × 7.3 (9-11 × 6-8), with a L/W of 1.3 (1.1-1.7); they have a broad Stieda body, lack sub- and parastieda bodies, and have a residuum of a few granules scattered throughout the sporocyst. Sporozoites were not clearly defined, but what seemed to be a single large refractile body is seen, presumably in each sporozoite.