In juvenile domestic pigs cold-induced shivering intensity decreases whereas mass specific metabolic rate (i.e. heat production) increases over the first days of life (data from Table 2 in Berthon et al. (1994)). This change in the ratio between shivering and metabolic rate leads to a >5-fold apparent improvement of shivering efficiency. We hypothesize that the enhancement of thermogenesis is due to an increasing contribution of SERCA-based futile Ca2+ cycling in skeletal muscles.