Habitat colour gradients characterise urban areas: from green prevailing in the least urbanised areas dominated by lawn, shrubs and trees, to grey characteristic of heavily urbanised areas dominated by impervious surfaces. These changes may promote modifications in community composition and intraspecific colour changes in species occurring in urban areas. This review's objectives were: (1) to analyse reported patterns of animal colour change between urban and non‐urban areas; (2) to identify the main mechanisms underlying those patterns; and (3) to determine research bias and suggest future research directions. A bibliometric on animal colour patterns using Scopus resulted in 62 studies being found and their findings assessed. Most studies were focused on birds (N = 38) and were conducted in the Northern Hemisphere (N = 55), with 90% analysing intraspecific colour changes. Intraspecific studies found three main patterns: (1) urban melanism, with polymorphic species of insects, birds and reptiles showing darker colouration in urban areas than in non‐urban areas; (2) urban dullness, with carotenoid‐based plumage colours being duller in urban than in rural areas; and (3) a reduction in conspicuousness of sexually selected plumages in urban areas. Interspecific studies suggested that urban areas are filters for animal colours, promoting the colonisation of those species that increase camouflage or exhibit warning colours to predators. More studies are needed in the Southern Hemisphere and at the interspecific level to determine the role of animal colours in urban colonisation.

中文翻译：

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城市的统一色彩：关于城市化对动物色彩影响的综述

人居地颜色梯度是城市地区的特征：从在以草坪，灌木和树木为主的城市化程度最低的最不发达地区流行的绿色，到以不透水的表面为主的城市化程度高的地区的灰色特征。这些变化可能会促进城市地区物种组成的改变和种内颜色的变化。这项审查的目标是：（1）分析城市和非城市地区之间报告的动物颜色变化模式；（2）确定这些模式背后的主要机制；（3）确定研究偏见并提出未来的研究方向。使用Scopus对动物的颜色模式进行了文献计量，结果发现了62项研究，并对他们的发现进行了评估。大多数研究都集中在鸟类（N= 38）并在北半球（N= 55），其中90％分析种内颜色变化。种内研究发现了三种主要模式：（1）城市黑色素病，与城市以外的地区相比，昆虫，鸟类和爬行动物的多态性物种显示出较深的颜色；（2）城市的钝感，以类胡萝卜素为基础的羽毛颜色在城市比在农村地区更暗淡；（3）减少市区内按性别挑选的羽毛的显眼性。种间研究表明，城市地区是动物色彩的过滤器，促进了那些增加伪装或向掠食者显示警告颜色的物种的定殖。为了确定动物色彩在城市殖民中的作用，需要在南半球和种间水平进行更多研究。