Full Name: Ivan Petrovich Pavlov; Profession: Russian physiologist, experimental neurologist and physician, pioneering researcher into digestion and conditioned reflexes, Nobel Prize laureate in Physiology or Medicine 1904 for work on digestive secretions; Nationality: Russian; Born: 14 September 1849 (Old Style; 26 September New Style), in the city of Ryazan in the Russian Empire; Birthplace: Ryazan, Russia; Generation: 19th‑century Russian scientific generation shaped by the late Imperial era and early Soviet transition, active in laboratories at St. Petersburg University, the Imperial Medical Academy, and the Institute of Experimental Medicine; Chinese Zodiac: Rooster (1849 is a Rooster year in the traditional Chinese 12‑year cycle); Zodiac Sign: Virgo (standard Western zodiac for births on September 14); Age in 2026: 177 years old if still alive (born 1849, died aged 86 in 1936); Marital Status: Married in 1881 to Seraphima (Seraphima Vasilievna) Karchevskaya, a teacher and physician’s daughter, with the marriage lasting until his death in Leningrad; Children: Five children in total, including his first son, Wirchik, who died young, followed by Vladimir, Victor, Vsevolod, and Vera, several of whom became academics or professionals in Soviet Russia; Description: Ivan Pavlov was born into the family of an Orthodox village priest but abandoned a planned religious career after encountering progressive scientific and literary ideas, instead devoting his life to physiology and experimental research on circulation, digestion and the nervous system; he studied at the University of St. Petersburg and the Imperial Medical Academy, trained under leading physiologists in Germany, and built a major laboratory in St. Petersburg where he developed chronic surgical techniques such as long‑term fistulas to study organ function under near‑normal conditions; through meticulous work on digestive secretions in dogs he discovered that salivation and gastric responses could be triggered by previously neutral stimuli associated with feeding, formulating the theory of conditioned reflexes that became foundational for behavioral psychology, learning theory, and later applications in education, advertising and psychotherapy; his classic experiments, in which dogs learned to salivate to sounds like bells or metronomes that had been repeatedly paired with food, showed how the nervous system encodes associations and how environmental signals can shape automatic bodily reactions; widely honored with the Nobel Prize and membership in scientific academies, Pavlov remained outspoken and sometimes critical of Soviet policies even as the regime celebrated his research, and his laboratory and home were later preserved as museums in recognition of his enduring influence on science and culture; Cause of Death: Pavlov died in Leningrad on 27 February 1936 at age 86 from double pneumonia, remaining intellectually engaged to the end and reportedly asking a student to document his dying process for scientific observation.