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Flatfish Camouflage Experiments (1911)

This great series of photographs comes from a 1911 paper in the Journal of Experimental Zoology by American ichthyologist and zoologist Francis Bertody Sumner. The images were captured a year earlier at the Naples Zoological Station in Italy and back home at the U.S. fisheries Laboratory at Woods Hole, in a series of experiments in which Sumner puts a various types of flounder through their paces as regards camouflage ability. Placing them against bold and striking patterns (more than they’d experience in nature), Sumner photographed them at various states of adapting to their new backgrounds — and concluded that the fish with the most favourable adaptive qualities was a small species of flounder named Rhomboidichthys podas. Although the fact that the photographs are in black and white (a limitation of the time) might slightly impinge on their scientific usefulness, it does somewhat enhance their aesthetic qualities, at times lending them an almost pop art air.

flatfish camouflage
Plate 2 — Views of specimen no. 1: f, on painted squares, 2 cm. sq. (after four days); g, do., 1 cm. sq. (after seven days); h, do., 1 cm. sq. (after four days); i, do., 2 mm. sq. (after one day).
flatfish camouflage
Plate 3 — Views of specimen no. 1: j, after three days on background figured; k, after fourteen days on white marble bottom (the fish was in reality much paler than the photograph would seem to indicate); l, after three days on the background figured; m, after six days on the background figured.
flatfish camouflage
Plate 4 — Views of specimen no. 2: a, on dark mixed sand, partly covered with this material (after two days); b, on white glass plate, shortly after transfer to this following sojourn on dark sand; c, on coarse gravel (after two days); d, on white glass plate, shortly after transfer to this, following sojourn on coarse gravel. (Compare this with b. In d, the gravel pattern has persisted to some degree, despite an immediate partial disappearance of this).
flatfish camouflage
Plate 5 — Views of specimen no. 2: e, upon fine gravel (after two or three days); f, upon dark, mixed sand after two days). Views of specimen no. 3: a, after one day on present ground; b, taken on the day when first placed on this sand. (Note the inferior power of adaptation shown by this fish, as compared with the last. The harmony with the backgrounds increased little if any beyond the condition shown in the photographs).
flatfish camouflage
Plate 6 — Views of specimen no. 3, in the ‘sand’ and ‘gravel’ phases. Unfortunately, the capacity of this specimen for such adaptations proved to be comparatively small.
flatfish camouflage
Plate 7 — Views of specimen no. 4: a, after six days on pattern shown; b, after three days on pattern shown (compare minutely with last); c, after nine days on the dark sand; d, after three days on the pattern shown; e, after three days on the pattern shown.
flatfish camouflage
Plate 8 — Views of specimen no. 4: f, after seven days on present background condition of rest); g, same, when preparing to swim; h, after one day on present background; i, after three days on a background of gray, of a shade approximately matching that produced on a color-wheel by the use of two parts of black and one of white. (The harmony between the fish and the bottom was really much greater than would seem to be the case from this photograph, which has made the fish seem darker). Specimen no. 5: view inserted to show a particularly striking gravel pattern (taken after eight days). (There are in reality a few particles of gravel on the back of the fish).