Johann Melchior Roos je izhajal iz slikarske družine. Njegov prvi učitelj je bil oče Johann Heinrich, ki je bil krajinar. Po očetovih stopinjah so šli štirje sinovi, med katerimi sta bila najbolj znana Philipp in Johann Melchior. Oba brata sta slikala živali. Kljub temu da je bil Philipp sposobnejši, se je Johannu Melchiorju obetala bolj bleščeča kariera: pokroviteljstvo bamberškega knezoškofa Lotharja Franza von Scönborna, ki je navdušeno kupoval slike z živalmi za opremo novozgrajenega gradu v Pommersfeldnu. Žal pa ga je Johann Melchior s svojo nezanesljivostjo in lenobo močno razočaral. Zaradi lahkotnega življenjskega sloga se je našega slikarja v Frankfurtu oprijelo ime Sobotni Roos. Slikal naj bi le ob sobotah, ko je njegova žena potrebovala denar za nakupe.
Sliki Mirna čreda in Preplašena čreda sta zasnovani kot sekvenčni par. Na prvi sta ob počivajoči čredi upodobljena speči pastir in budni pes čuvaj, druga slika pa kaže panični beg črede, ki jo z leve napada volk. V ozadju vidimo, da vsiljivca preganjajo psi in kmet s puško.
Slikanje živali je postalo priljubljeno v renesansi, še posebno pa se je razmahnilo od 16. stoletja dalje. V 17. stoletju so nekateri flamski slikarji – denimo Jan Fyt in Frans Snyders –, ki so se specializirali za slikanje živali, postali izjemno uspešni in vplivni. Tudi v slikah Johanna Melhiorja Roosa odmevajo motivne in kompozicijske rešitve animalistov antwerpenske šole 17. stoletja.
Johann Melchior Roos was a member of a family of painters. His first teacher was his father, Johann Heinrich, a landscape painter. Following in the footsteps of their father were four sons, among whom Philipp and Johann Melchior are the most known. Both brothers painted animals. Although Philipp was more competent, Johann Melchior had a more promising career in front of him: Prince Bishop of Bamberg, Lothar Franz von Schönborn, became his patron, and was enthusiastically buying animal paintings for the newly-built Pommersfelden Castle. Unfortunately, he was greatly disappointed by Johann Melchior’s unreliability and laziness. The people in Frankfurt knew of the painter’s easy-going lifestyle and nicknamed him “Saturday Roos”. It was said that he only painted on Saturdays, when his wife needed money to go shopping.
The paintings A Herd at Rest and A Frightened Herd were meant as a sequential pair. The first painting shows a resting herd with the sleeping herdsman and his alert watchdog, while the second painting depicts the herd fleeing in fear, as a wolf attacks from the left. In the background we see that the intruder is being chased by dogs and a farmer with a gun.
Animal paintings became popular in the Renaissance and gained an even wider acceptance from the 16th century onwards. In the 17th century, some Flemish painters, like Jan Fyt and Frans Snyders, specialized in animal painting and became very successful and influential. The paintings of Johann Melchior Roos echo the motifs and compositional solutions of the animal painters of the 17th century Antwerp School.