RT Journal Article
T1 Nocturnal camouflage through background matching against moonlight
A1 Negro, Juan J.
A1 Bará Viñas, Salvador
A1 Galadí Enríquez, David
A1 Nieves, Juan Luis
A1 Martínez Domingo, Miguel A.
A1 Ferrero, Alejandro
A1 Campos, Joaquín
A1 Bao Varela, María del Carmen
A1 Masana, Eduard
A1 Camacho, Carlos
K1 Phenotype-time correlations
K1 Posch ratio
K1 Moon
K1 Avian predators
K1 Barn owl
AB Camouflage is often considered a daytime phenomenon based on light and shade. Nocturnal camouflage can also occur, but its mechanistic basis remains unclear. Here, we analyze the conditions for background matching (BM) of avian predators against the night sky. Such concealment is achieved when the contrast between the predator and the sky is smaller than the contrast detection threshold of prey. This condition cannot be fulfilled under isotropic skies, as in fully overcast or moonless nights. However, on clear moonlit nights, the isotropy of the sky radiance is broken due to the presence ofthe Moon, and the conditions for BM can be met for a wide range of sky directions. This effect is mainly dependent on the altitude of the Moon above the horizon, rather than on Moon phase. We have modeled the feasibility of concealment through BM of a typically white barn owl (Tyto alba) when hunting rodents, based on its contrast against the moonlit sky. We considered the radiometric quantities of the sky, the ground, and the bird’s undersides. Our results show that a barn owl with highly reflecting underparts may approach a rodent from broad regions of the moonlit sky while keeping itself below thecontrast detection threshold of the mouse M-cones and rods. S-cones, in turn, remain below their excitation threshold for most of the lunar cycle. Our results demonstrate that the white color of barn owls serves as camouflage tailored to the moonlit sky background, providing a mechanistic basis for understanding nocturnal camouflage.
PB PNAS
SN 0027-8424
YR 2024
FD 2024-12-16
LK https://hdl.handle.net/10347/44208
UL https://hdl.handle.net/10347/44208
LA eng
NO J.J. Negro,S. Bará,D. Galadí-Enríquez,J.L. Nieves,M.A. Martínez-Domingo,A. Ferrero,J. Campos,C. Bao-Varela,E. Masana, & C. Camacho,  Nocturnal camouflage through background matching against moonlight, Proc. Natl. Acad. Sci. U.S.A. 122 (1) e2406808121, https://doi.org/10.1073/pnas.2406808121 (2025)
DS Minerva
RD 29 abr 2026