The giant panda is cryptic

Ossi Nokelainen,Fuwen Wei,Nicholas E Scott-Samuel,Tim Caro,Yonggang Nie

doi:10.1038/s41598-021-00742-4

Abstract

The giant panda (Ailuropoda melanoleuca) is an iconic mammal, but the function of its black-and-white coloration is mysterious. Using photographs of giant pandas taken in the wild and state-of-the-art image analysis, we confirm the counterintuitive hypothesis that their coloration provides camouflage in their natural environment. The black fur blends into dark shades and tree trunks, whereas white fur matches foliage and snow when present, and intermediate pelage tones match rocks and ground. At longer viewing distances giant pandas show high edge disruption that breaks up their outline, and up close they rely more on background matching. The results are consistent across acuity-corrected canine, feline, and human vision models. We also show quantitatively that the species animal-to-background colour matching falls within the range of other species that are widely recognised as cryptic. Thus, their coloration is an adaptation to provide background matching in the visual environment in which they live and simultaneously to afford distance-dependent disruptive coloration, the latter of which constitutes the first computational evidence of this form of protective coloration in mammals.

Highlights

The giant panda (Ailuropoda melanoleuca) is an iconic mammal, but the function of its black-andwhite coloration is mysterious
We examined difficult-to-obtain photographs of 15 giant pandas taken in the wild using the Multispectral Image Calibration and Analysis (MICA) toolbox[17] and the Quantitative Colour and Pattern Analysis (QCPA) framework[18], which together provide state-of-the-art image analysis[17,18,19,20], to establish whether or not giant pandas are camouflaged either through background matching or disruptive coloration, or both
Quantification of background matching: how does the patchiness of the black‐and‐white col‐ oration blend into the visual environment? The giant panda pelage patches were significantly associated with visual elements found in their natural habitat (Chi-Square test for independence, χ2 = 89.01, df = 10, p < 0.001)

Summary

Introduction

The giant panda (Ailuropoda melanoleuca) is an iconic mammal, but the function of its black-andwhite coloration is mysterious. We show quantitatively that the species animal-to-background colour matching falls within the range of other species that are widely recognised as cryptic Their coloration is an adaptation to provide background matching in the visual environment in which they live and simultaneously to afford distance-dependent disruptive coloration, the latter of which constitutes the first computational evidence of this form of protective coloration in mammals. Dark areas are associated with shade in carnivores and ursids, suggesting these parts of the giant panda’s pelage might keep the animal camouflaged in shaded forested a reas[12] This dual function coloration could be driven by the need of this species to traverse two very different visual backgrounds (winter and summer habitat) during the course of the year, because their diet prevents them from hibernating as do some other Ursidae[11].

Methods

Results

Conclusion