The crested rat, Lophiomys imhausi, is the only mammal known to sequester plant toxins. Found in eastern Africa, this large rodent is thought to defend against predation by coating specialized hairs along its sides with cardenolide toxins from the poison arrow tree, Acokanthera schimperi. To better understand the ecology of this unusual poisonous mammal, we used camera traps, livetrapping, and captive behavioral observations, to study L. imhausi in central Kenya. Although crested rats were rarely detected with camera traps, 25 individuals were caught in live traps, with estimated densities of up to 15 rats/km² at one of nine trapping sites. Trapping records and behavioral observations suggest that L. imhausi live in male–female pairs, with juveniles that might exhibit delayed dispersal. We observed chewing of A. schimperi and/or anointing in 10 of 22 individuals, confirming the previous poison sequestration observation. We monitored crested rat activity using cameras and found that chewing on A. schimperi and cardenolide exposure had no effect on feeding, movement, or total activity. One crested rat also fed on milkweed (Gomphocarpus physocarpus; Gentaniales: Apocynaceae), but did not anoint with this cardenolide containing plant. This observation, combined with L. imhausi’s selective use of A. schimperi, suggests the potential for use of alternative poison sources. This research provides novel insight into the ecology of L. imhausi, while also suggesting that more field observations, feeding trials, and chemical analyses are needed to understand their behavior and physiology. Furthermore, their complex social interactions, slow life history, and fragmented populations suggest that L. imhausi could be at risk of decline.

中文翻译：

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非洲凤头鼠 Lophiomys imhausi 的秘密社交生活

凤头鼠Lophiomys imhausi是已知的唯一一种能够隔离植物毒素的哺乳动物。这种在非洲东部发现的大型啮齿动物被认为通过在其两侧的特殊毛发上涂上来自毒箭树Acokanthera schimperi 的cardenolide 毒素来抵御捕食。为了更好地了解这种不寻常的有毒哺乳动物的生态，我们使用相机陷阱、活体诱捕和圈养行为观察来研究肯尼亚中部的L. imhausi。尽管相机陷阱很少检测到凤头鼠，但有 25 个人被活陷阱捕获，在九个诱捕地点之一，估计密度高达 15 只老鼠/km ²。诱捕记录和行为观察表明L. imhausi雌雄成对生活，幼鱼可能会延迟扩散。我们观察到22 人中有 10 人咀嚼A. schimperi和/或涂油，证实了之前的毒物隔离观察。我们使用相机监测了冠毛鼠的活动，发现咀嚼A. schimperi和 Cardenolide 暴露对进食、运动或总活动没有影响。一只冠毛鼠也以马利筋（Gomphocarpus physocarpus ; Gentaniales：夹竹桃科）为食，但没有涂上这种含有cardenolide 的植物。这一观察结果，结合L. imhausi对A. schimperi的选择性使用, 表明使用替代毒物来源的潜力。这项研究提供了对L. imhausi生态学的新见解，同时也表明需要更多的实地观察、喂养试验和化学分析来了解它们的行为和生理学。此外，它们复杂的社会互动、缓慢的生活史和支离破碎的种群表明L. imhausi可能面临衰退的风险。