Standard Metabolism of Monotremes and the Evolution of Homeothermy.

1979 ◽  
Vol 27 (4) ◽  
pp. 511 ◽  
Author(s):  
TJ Dawson ◽  
TR Grant ◽  
D Fanning
Keyword(s):  
Metabolic Rates ◽  
Body Temperatures ◽  
Standard Metabolism ◽  
Metabolic Capability ◽  
Gradual Evolution ◽  
Ornithorhynchus Anatinus ◽  
The Family ◽  
Tachyglossus Aculeatus

The standard metabolic rates (SMR) of species from all extant monotreme genera were determined together with body temperatures. The echidnas, Zaglossus bruijni and Tachyglossus aculeatus, of the Family Tachyglossidae, both had an SMR 25-30% of predicted eutherian levels. The platypus Ornithorhynchus anatinus, however, had a much higher SMR. The weight-independent values (watts, kg*-075) were 0.86, 0.98 and 2.21 respectively for Z. bruijni, T. aculeatus and 0. anatinus. Body temperatures were similar, however, with means in the range 31.3-32�C. The data are suggested to support the idea of a gradual evolution in metabolic capability rather than marked jumps in metabolic levels.

The standard energetics of mammalian carnivores: Felidae and Hyaenidae

2000 ◽  
Vol 78 (12) ◽  
pp. 2227-2239 ◽  
Author(s):  
Brian K McNab
Keyword(s):  
Energy Expenditure ◽  
Metabolic Rate ◽  
Basal Metabolic Rate ◽  
Body Temperatures ◽  
Basal Rate ◽  
The Family ◽  
Small Muscle ◽  
Arboreal Habit ◽  
High Basal Metabolic Rate ◽  
Low Rate

Data concerning the energy expenditure of nine species in the family Felidae and one species in the family Hyaenidae are presented, all of which were obtained under standard conditions. An examination of basal rates of metabolism in these felids and in two species reported in the literature indicates that basal rate is primarily correlated with body mass; of these species, nine have a high basal metabolic rate by general mammalian standards, the two exceptions being the margay and jaguarundi. The low basal metabolic rate of the margay may be related to its arboreal habit in association with small muscle mass, but the reason for the low rate in the jaguarundi is unknown. The omnivorous striped hyaena and termitivorous aardwolf have typical mammalian basal rates. Felids that weigh less than 7 kg have slightly low minimal thermal conductances relative to mammals generally; larger species have high conductances. Felids have slightly high body temperatures.

Body Temperatures of Free-Ranging Platypuses, Ornithorhynchus anatinus (Monotremata), with Observations on their Use of Burrows

1983 ◽  
Vol 31 (2) ◽  
pp. 117 ◽  
Author(s):  
TR Grant
Keyword(s):  
Thermal Stresses ◽  
Cold Water ◽  
Body Temperatures ◽  
Ornithorhynchus Anatinus ◽  
The Face ◽  
Free Ranging

Body temperatures (T*h) of free-ranging platypuses were monitored by means of radiotelemetry; although fluctuations of up to 2.8�C occurred in some individuals, most T*b measured were close to 32�C, even during immersion in cold water for up to 12 h. Platypuses spent up to 51% of their day foraging in water, and during such activities 71% of the animals studied used more than one particular burrow. One platypus maintained its T*b, while swimming in water of 0�C in a partly frozen river for at least 5 h. The platypus is a competent homeotherm which maintains a constant T*b in the face of the considerable thermal stresses imposed on it during winter in the southern part of its range.

Silurian Ramphoprionid polychaetes from Gotland, Sweden

2001 ◽  
Vol 75 (5) ◽  
pp. 993-1015 ◽  
Author(s):  
Mats Eriksson
Keyword(s):  
New Species ◽  
New Genus ◽  
Morphological Changes ◽  
Original Description ◽  
Surface Structures ◽  
New Genus And Species ◽  
Gradual Evolution ◽  
The Family ◽  
Stratigraphic Ranges ◽  
Stratigraphic Range

Silurian ramphoprionid polychaete annelids, represented by their jaws (scolecodonts), are described from extensive collections from Gotland, Sweden. The family Ramphoprionidae, monotypic at its original description, is sub-divided into four genera; Protarabellites Stauffer, 1933; Ramphoprion Kielan-Jaworowska, 1962; “Pararamphoprion” Männil and Zaslavskaya, 1985; and Megaramphoprion new genus. Identified species include “P.” cf. nordicus Männil and Zaslavskaya, 1985; P. rectangularis new species; P. staufferi new species; P. triangularis new species; and two Protarabellites species left in open nomenclature. Ramphoprion is represented by one new highly plastic species, R. gotlandensis, housing five distinguishable morphotypes showing gradual evolution. Megaramphoprion, which is most closely related to Ramphoprion, is represented by M. magnus new genus and species, a rare but distinctive taxon. Most species have long stratigraphic ranges within which important morphological changes can nonetheless be observed. The stratigraphic range of ramphoprionids includes, at least, the Ordovician to the Silurian. They are fairly rare in the Silurian of Gotland and where present they generally form less than 10 percent of the polychaete faunas, although occasionally reaching as much as 20 to 30 percent. Evolution, paleoecology, and surface structures of the investigated species are briefly discussed.

scholarly journals THE METABOLIC RATES AND BODY TEMPERATURES OF BATS

1951 ◽  
Vol 101 (3) ◽  
pp. 289-299 ◽  
Author(s):  
RAYMOND J. HOCK
Keyword(s):  
Metabolic Rates ◽  
Body Temperatures

Standard metabolic rate and preferred body temperatures in some Australian pythons

1998 ◽  
Vol 46 (4) ◽  
pp. 317 ◽  
Author(s):  
Gavin S. Bedford ◽  
Keith A. Christian
Keyword(s):  
Oxygen Consumption ◽  
Body Temperature ◽  
Metabolic Rate ◽  
Thermal Sensitivity ◽  
Standard Metabolic Rate ◽  
Allometric Equations ◽  
Metabolic Rates ◽  
Body Temperatures ◽  
Daily Cycle ◽  
Preferred Body Temperature

Pythons have standard metabolic rates and preferred body temperatures that are lower than those of most other reptiles. This study investigated metabolic rates and preferred body temperatures of seven taxa of Australian pythons. We found that Australian pythons have particularly low metabolic rates when compared with other boid snakes, and that the metabolic rates of the pythons did not change either seasonally or on a daily cycle. Preferred body temperatures do vary seasonally in some species but not in others. Across all species and seasons, the preferred body temperature range was only 4.9˚C. The thermal sensitivity (Q10) of oxygen consumption by pythons conformed to the established range of between 2 and 3. Allometric equations for the pooled python data at each of the experimental temperatures gave an equation exponent of 0.72–0.76, which is similar to previously reported values. By having low preferred body temperatures and low metabolic rates, pythons appear to be able to conserve energy while still maintaining a vigilant ‘sit and wait’ predatory existence. These physiological attributes would allow pythons to maximise the time they can spend ‘sitting and waiting’ in the pursuit of prey.

scholarly journals Heart rate reveals torpor at high body temperatures in lowland tropical free-tailed bats

2017 ◽  
Vol 4 (12) ◽  
pp. 171359 ◽  
Author(s):  
M. Teague O'Mara ◽  
Sebastian Rikker ◽  
Martin Wikelski ◽  
Andries Ter Maat ◽  
Henry S. Pollock ◽  
...  
Keyword(s):  
Heart Rate ◽  
Body Temperature ◽  
Metabolic Rate ◽  
Ambient Temperature ◽  
The Body ◽  
Metabolic Rates ◽  
Body Temperatures ◽  
Wide Range ◽  
Save Energy ◽  
Molossus Molossus

Reduction in metabolic rate and body temperature is a common strategy for small endotherms to save energy. The daily reduction in metabolic rate and heterothermy, or torpor, is particularly pronounced in regions with a large variation in daily ambient temperature. This applies most strongly in temperate bat species (order Chiroptera), but it is less clear how tropical bats save energy if ambient temperatures remain high. However, many subtropical and tropical species use some daily heterothermy on cool days. We recorded the heart rate and the body temperature of free-ranging Pallas' mastiff bats ( Molossus molossus ) in Gamboa, Panamá, and showed that these individuals have low field metabolic rates across a wide range of body temperatures that conform to high ambient temperature. Importantly, low metabolic rates in controlled respirometry trials were best predicted by heart rate, and not body temperature . Molossus molossus enter torpor-like states characterized by low metabolic rate and heart rates at body temperatures of 32°C, and thermoconform across a range of temperatures. Flexible metabolic strategies may be far more common in tropical endotherms than currently known.

Sign in / Sign up

Export Citation Format

Share Document