Leanness of Lou/C rats does not require higher thermogenic capacity of brown adipose tissue

► Leanness of Lou/C rats does not require thermogenic processes in BAT. ► BAT is not deficient in Lou/C rats as it can be stimulated by prolonged cold exposure. ► High spontaneous locomotor activity could partly explain leanness of this strain. ► Substitution between thermogenic processes by BAT and locomotor activity could appear at 4 °C.