title: Cool echidnas survive the fire.
abstract: Fires have occurred throughout history, including those associated with the meteoroid impact at the Cretaceous-Palaeogene (K-Pg) boundary that eliminated many vertebrate species. To evaluate the recent hypothesis that the survival of the K-Pg fires by ancestral mammals was dependent on their ability to use energy-conserving torpor, we studied body temperature fluctuations and activity of an egg-laying mammal, the echidna (Tachyglossus aculeatus), often considered to be a 'living fossil', before, during and after a prescribed burn. All but one study animal survived the fire in the prescribed burn area and echidnas remained inactive during the day(s) following the fire and substantially reduced body temperature during bouts of torpor. For weeks after the fire, all individuals remained in their original territories and compensated for changes in their habitat with a decrease in mean body temperature and activity. Our data suggest that heterothermy enables mammals to outlast the conditions during and after a fire by reducing energy expenditure, permitting periods of extended inactivity. Therefore, torpor facilitates survival in a fire-scorched landscape and consequently may have been of functional significance for mammalian survival at the K-Pg boundary.
authors.affiliation: Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, New South Wales 2351, Australia Department of Environment and Agriculture, Curtin University, Perth, Western Australia 6845, Australia jnowack@une.edu.au.
authors.forename: Julia
authors.initials: J
authors.lastname: Nowack
authors.affiliation: Department of Environment and Agriculture, Curtin University, Perth, Western Australia 6845, Australia School of Animal Biology M092, University of Western Australia, Crawley 6009, Western Australia, Australia.
authors.forename: Christine Elizabeth
authors.initials: CE
authors.lastname: Cooper
authors.affiliation: Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, New South Wales 2351, Australia.
authors.forename: Fritz
authors.initials: F
authors.lastname: Geiser
mesh_terms: D000818:Animals; D001831:Body Temperature; D005390:Fires; D008136:Longevity; D004442:Tachyglossidae / Q000502:physiology*; D064348:Torpor
keywords: activity; body temperature; food reduction; prescribed burn; torpor