Attachment theory was built around the idea that infants rely on others to survive, and it is often forgotten that survival hinged on coping with environmental demands. Adult attachment reports have instead been organized around people's subjective experience of safety and security in relationships. To resolve the gap between infant's physical needs and adult attachment experiences, we made a first step by developing the Social Thermoregulation and Risk Avoidance Questionnaire (STRAQ-1) in 12 countries (N = 1510), providing a complementary measure to identify biological drives formative to attachment. We conjectured that co-regulatory patterns of temperature and stress are foundational to attachment styles and on this basis used a naive bootstrapping method to find a robust solution, conducting seven exploratory factor analyses in an exploratory-confirmatory fashion. We identified 23 (out of 57) items in 4 subscales: Social Thermoregulation (Total Omega = .83), High Temperature Sensitivity (.83), Solitary Thermoregulation (.77), and Risk Avoidance (.57). In terms of external validity, we also found that the STRAQ-1 relates to emotion regulation strategies broadly and, importantly, relates to individual differences in attachment specifically, which in turn mediates the relationship with stress and health (making the scale face valid). Our approach provides a robust first effort in identifying biological mechanisms underlying attachment formation.