The Mouse-To-Elephant Metabolic Curve: Historical Overview.

Although it is intuitive that large mammals need more food than smaller ones, it is not so obvious that, relative to their body mass, larger mammals consume less than smaller ones. In fact, on a per kg basis, the resting metabolic rate of a mouse is some 50 times higher than that of an elephant. The fact that metabolism could not be proportional to the mass of the animal was suggested by Sarrus and Rameaux in 1838.

Respiratory sinus arrhythmia magnitude quantification as a potential marker of stress and pain in cows and sheep.

Respiratory sinus arrhythmia (RSA) provides a quantitative evaluation of 'vagal tone' and may be used for pain and stress assessment in livestock. The aim was to quantify the magnitude of RSA in cows and sheep. In 7 cows and 4 sheep standing at rest we measured the 3-lead electrocardiogram (ECG) together with the pneumogram, to identify inspiration and expiration.

Breath-by-breath analysis of respiratory sinus arrhythmia in dogs.

Dogs differ greatly in size, heart (HR) and breathing rates (BR). In addition, they have a clear Respiratory Sinus Arrhythmia (RSA) at rest. Therefore, better than any other mammalian species, dogs offer an opportunity to test whether resting RSA varies with body weight, HR or BR.

Social interaction and the thermogenic response of chicken hatchlings.

The aggregation of two or more individuals of the same species (huddling) is common in mammals and birds, especially in the cold. The physical contact reduces the weight-specific body surface exposed to the environment, thus lowering heat loss and the thermogenic needs. This study investigated the possibility that the mere presence of a conspecific, in absence of physical contact, may by itself influence metabolic rate during cold.

Respiratory sinus arrhythmia during a mental attention task: the role of breathing-specific heart rate.

It is known that a mental attention task (MAT) can modify the magnitude of the increase in instantaneous heart rate (HR) with inspiration, or Respiratory Sinus Arrhythmia (RSA). Here, we asked whether the RSA changes were mediated by the changes in HR, breathing frequency (f) or HR/f ('breathing specific heart rate'). This latter reflects the degree of coupling between pulmonary blood and air flows, the optimization of which may be the function of RSA.