[1] Born in Bordeaux, Jules was the third child of Christine Dorotheé Sophie Marquis (1797–1833), a musician, and Oscar-Raymond Bonheur (1796–1849) (a landscape and portrait painter and an early adherent of Saint-Simonianism, a Christian-socialist sect that promoted the education of women alongside men).

[2] "It is I who first gave modeling and sculpture lessons to my brother Isidore" (Rosa Bonheur)[3] In Bordeaux his father had been friends with Francisco Goya who was living there in exile.

[4] He studied painting at first, enrolling in 1849 at the École nationale supérieure des Beaux-Arts, though he made his debut at the Salon (Paris) in 1848 (a Cavalier nègre attaqué par une lionne, plaster, and a drawing of the same subject) and exhibited regularly until 1899.

[9] The Peyrol casts for both Rosa and Isidore Bonheur are exceptionally well executed, which suggests a strong working relationship between the founder and sculptor.

There is little doubt that Isidore Bonheur was an acute observer of nature; his animals were not anthropomorphized, but modelled to catch movement or posture characteristic of the particular species.