“…Warm stimuli, in particular, are attractive: rat pups approach and huddle with a variety of animate and inanimate sources of heat (Alberts, 1978;Alberts & Brunjes, 1978;Brunjes & Alberts, 1979;Cosnier, 1965). Moreover, temperature cues have been shown to be effective reinforcers for associative learning in small, thermally fragile, infant organisms (Martin & Alberts, 1982;Taylor, Sluckin, & Hewitt, 1969). Perhaps the power of "maternal" stimuli, as they bear on the establishment of olfactory huddling preferences, derives from the thermal consequences of contact interaction.…”