The great desert skink (Liopholis kintorei) of the Egerniinae subfamily (Reptilia: Scincidae) is a communal burrowing lizard that inhabits arid spinifex grasslands in central Australia. Great desert skink activity is centred in and around the burrows which are inhabited for many years. However, it is not known whether skinks select burrow sites with specific attributes or how continuing occupancy of burrows is influenced by the surrounding habitat; especially post‐fire, when plant cover is reduced. Here, we test whether great desert skink burrows in areas burnt 2 years previously and in longer unburnt areas are associated with particular habitat attributes, and whether there are differences between occupied and recently abandoned burrow sites. Vegetation composition, cover and soil surface characteristics at 56 established great desert skink burrows, including occupied and recently unoccupied burrows, were compared with 56 random nearby non‐burrow control sites. Burrow sites had higher plant cover compared with the surrounding landscape in both recently burnt and longer unburnt areas and were more likely to be associated with the presence of shrubs. Soil stability and infiltration were also higher at burrow sites. However, we found no evidence that burrows with lower cover were more likely to be abandoned. Our results suggest that great desert skinks may actively select high cover areas for burrow construction, although differences between burrow and control sites may also partly reflect local changes to plant cover and composition and soil properties resulting from burrow construction and long‐term habitation of a site. Further research should determine if burrows with shrubs or higher plant cover provide greater protection from predators, more structural stability for burrow construction, increased prey abundance or other benefits. We recommend that maintenance of areas with relatively higher plant cover be prioritized when managing great desert skink habitat. 相似文献
Small herbivores face risks of predation while foraging and are often forced to trade off food quality for safety. Life history, behaviour, and habitat of predator and prey can influence these trade‐offs. We compared how two sympatric rabbits (pygmy rabbit, Brachylagus idahoensis; mountain cottontail, Sylvilagus nuttallii) that differ in size, use of burrows, and habitat specialization in the sagebrush‐steppe of western North America respond to amount and orientation of concealment cover and proximity to burrow refuges when selecting food patches. We predicted that both rabbit species would prefer food patches that offered greater concealment and food patches that were closer to burrow refuges. However, because pygmy rabbits are small, obligate burrowers that are restricted to sagebrush habitats, we predicted that they would show stronger preferences for greater cover, orientation of concealment, and patches closer to burrow refuges. We offered two food patches to individuals of each species during three experiments that either varied in the amount of concealment cover, orientation of concealment cover, or distance from a burrow refuge. Both species preferred food patches that offered greater concealment, but pygmy rabbits generally preferred terrestrial and mountain cottontails preferred aerial concealment. Only pygmy rabbits preferred food patches closer to their burrow refuge. Different responses to concealment and proximity to burrow refuges by the two species likely reflect differences in perceived predation risks. Because terrestrial predators are able to dig for prey in burrows, animals like pygmy rabbits that rely on burrow refuges might select food patches based more on terrestrial concealment. In contrast, larger habitat generalists that do not rely on burrow refuges, like mountain cottontails, might trade off terrestrial concealment for visibility to detect approaching terrestrial predators. This study suggests that body size and evolutionary adaptations for using habitat, even in closely related species, might influence anti‐predator behaviors in prey species. 相似文献
A fossil discovery in the mid-Cretaceous Blackleaf Formation of southwest Montana, USA, has yielded the first trace and body fossil evidence of burrowing behaviour in a dinosaur. Skeletal remains of an adult and two juveniles of Oryctodromeus cubicularis gen. et sp. nov. a new species of hypsilophodont-grade dinosaur, were found in the expanded distal chamber of a sediment-filled burrow. Correspondence between burrow and adult dimensions supports Oryctodromeus as the burrow maker. Additionally, Oryctodromeus exhibits features of the snout, shoulder girdle and pelvis consistent with digging habits while retaining cursorial hindlimb proportions. Association of adult and young within a terminal chamber provides definitive evidence of extensive parental care in the Dinosauria. As with modern vertebrate cursors that dig, burrowing in Oryctodromeus may have been an important adaptation for the rearing of young. Burrowing also represents a mechanism by which small dinosaurs may have exploited the extreme environments of polar latitudes, deserts and high mountain areas. The ability among dinosaurs to find or make shelter may contradict some scenarios of the Cretaceous-Paleogene impact event. Burrowing habits expand the known range of nonavian dinosaur behaviours and suggest that the cursorial ancestry of dinosaurs did not fully preclude the evolution of different functional regimes, such as fossoriality. 相似文献
1. 1.|Thermoregulatory measurements of two Nambi rodents; Gerbillurus paeba, a burrow dweller, and Aethomys namaquensis, a crevice dweller were compared. Both were similar to other small arid-adapted rodents in that basal metabolic rates were reduced, thermoneutral zones narrow and evaporative water losses low. Rates of conductance and thermal lability, however, at ambient temperatures (Ta) below thermoneutral zone, were significantly different (P 0.01).
2. 2.|The rock rat A. namaquensis, living in a microclimate characterized by a large diel range and low humidities, compensates for a reduced basal metabolic rate by having a low rate of conductance. In this way it maintains precise thermoregulatory control. G. paeba, on the other hand, living in a thermally-stable milieu, does not control body temperature precisely. This animal instead utilizes a high rate of conductance to remove metabolic heat produced within the body. This would be advantageous to an animal living in a plugged burrow where the high humidities encountered impede the rate of evaporative cooling.
3. 3.|The energetic responses of both species, above the thermoneutral zone, appear to reflect very closely the environmental conditions which occur in the microhabitat that they rest in during the day. G. paeba shows less tolerance to temperature fluctuations than A. namaquensis, but shows more marked increases in short-term cooling mechanisms at high Tas.
4. 4.|Despite the increased use of evaporative cooling through salivation and panting in addition to pulmocutaneous evaporation, exposure to Tas above 38°C is rapidly lethal to G. paeba.
Planolites, although strictly a junior synonym of Palaeophycus, can be retained as a valid ichnotaxon on the basis of stability of nomenclature. As emended by Pemberton and Frey (1982) and consistently adopted by later authors, Planolites is diagnosed primarily on the basis that it is an unlined simple burrow, whereas Palaeophycus is a lined burrow. Other ichnotaxobases and ethological considerations are, without exception, subordinate to this directive. 相似文献