Although adult cane toads (Rhinella marina) are generally active only at night, a recent study reported that individuals of this species switched to diurnal activity in response to encountering a novel habitat type (deeply shaded gorges) in the course of their Australian invasion. Our sampling over a broader geographic scale challenges the idea that this behaviour is novel; we documented diurnal behaviour both in the species’ native range and in several sites within the invaded range, in multiple habitat types. Diurnal activity was most common in the tropics and in areas where toads attain high population densities and are in poor body condition, suggesting that the expansion of activity times may be induced by intraspecific competition for food.

尽管成年的蟾蜍蟾蜍（Rhinella marina）通常仅在夜间活动，但最近的一项研究报告称，该树种的个体由于在澳大利亚入侵过程中遇到一种新型的栖息地类型（深阴影的峡谷）而转向了昼夜活动。我们在更广泛的地理范围内进行抽样调查，挑战了这种行为是新颖的观念。我们记录了该物种的自然范围以及在受侵袭范围内的多个地点，多种生境类型中的昼夜行为。昼夜活动在热带地区以及蟾蜍的种群密度较高且身体状况较差的地区最为普遍，这表明活动时间的延长可能是由于种内食物竞争而引起的。