Burrowing and huddling in newborn porcupine: The effect on thermoregulation

Abstract

huddling in newborn porcupine. rile eflec/ 011 thl'rmoreg II/arion. PHYSIOI. BEHAV 52(2) 247-250, 1992.-The newborn cape porcupine Hystrix aji'icocallslralis is a precocial rodent. However, the newborn spends its first 9 weeks in the burrow. Heat production (oxygen consumption-I/o,) and body temperature (Th ) were measured at various ambient temperatures (Tal in newborn (4-8-week-old) porcupines. with a body mass between 1340-1993 g during summer. from the colony kept at the Mammal Research Institute, University of Pretoria. To assess the effect of huddling. these parameters were also measured in adult pairs of porcupines (Ta = 15 and 25°C) kept together in the metabolic chamber and the values were compared with those obtained from single porcupines. Overall minimal thermal conductance was calculated for newborn and paired adult porcupines. The newborn porcupines can regulate their body temperature at Tas between 1O-28 D C. VO, measured at lower critical point is 0.602 ± 0.08 mlj02/g' h. At Ta = 100e, Vo, oscillated with a characteristic amplitude and frequency. while body temperature was well regulated. Huddling decreases the lower critical point. The overall minimal thermal conductance (0.044 ± 0.002 ml 02/g' h . I DC) is higher than expected from body mass, so that the young are liable to lose heat rapidly. It is well known that the newborn porcupine spends a long period in the burrow and the results of this study suggest that this may be in order to conserve energy and presumably allocate it to growth. Apart from decreasing vulnerability. delaying foraging also avoids heat loss in the newborn porcupine.

Keep Calm and Cuddle on: Social Touch as a Stress Buffer

“…Huddling in infant mammals is a major type of social thermoregulation that allows reduction of heat loss while lowering energetic metabolic costs of endothermoregulation (Gilbert et al 2007, Morrison et al 2008, Nakamura and Morrison 2008aGilbert et al 2010). Huddling in newborn porcupines (Hystrix africaeaustralis), for example, lowers the critical temperature at which they can effectively thermoregulate by endogenous means (Haim et al 1992). Importantly, these decreases enable gains in energy allocation for other important processes, such as growth, healing, and cell repair.…”

One for all and all for one: the energetic benefits of huddling in endotherms

“…Huddling allows newborn altricial mammals to reduce loss of energy as heat and thereby increase their growth rate (mice: Stanier, 1975; rats: Alberts, 1978 a ; Cape porcupines Hystrix africaeaustralis : Haim, Van Aarde & Skinner, 1992; rabbits: Bautista et al , 2003; Gilbert et al , 2007 a ). Benefits of huddling on growth rates are indeed particularly evident for newborns of altricial species, which huddle in the nest soon after birth.…”

Social organization and space use in the Cape porcupine in a Southern African savanna

“…The main benefits of group living for porcupines are probably thermoregulatory huddling (Haim, Van Aarde & Skinner, 1992), the cooperative rearing of offspring, the sharing of burrows and possibly the cooperative maintenance of territories. However, the incident in which a burrow was taken over immediately following the death of one pair member, suggests that the pair-bond may provide an extra incentive to maintain a territory, even if both pair members are not directly engaged in territorial maintenance.…”