Researchers in Germany have identified a previously unknown biological mechanism that enables homing pigeons to navigate via Earth's magnetic field using specialized cells in the liver.

德國研究人員發現了一項此前未知的生物機制，使信鴿能利用肝臟中的專門細胞，根據地球磁場進行導航。

The capacity for long-distance navigation in Columba livia has been documented since antiquity, with historical applications ranging from ancient Greek athletic notifications to the strategic intelligence operations of the British military during World War II, such as Operation Columba. While the existence of magnetoreception has been acknowledged for approximately a century, the precise physiological apparatus remained elusive, with prior hypotheses focusing on the ocular, cranial, or auditory regions.

原鴿（Columba livia）的長距離導航能力自古以來便有記載，歷史應用範圍廣泛，從古希臘的體育賽事通知到第二次世界大戰期間英國軍隊的戰略情報行動（如「鴿子行動」）均包含在內。儘管磁感應的存在已獲認可約一個世紀，但精確的生理構造仍不清楚，先前的假設集中在眼部、顱骨或聽覺區域。

Recent investigations conducted by the University of Bonn and the Max Planck Institute of Animal Behavior, published in the journal Science, suggest that the liver serves as a critical site for magnetic perception. The researchers utilized morphological and genomic assays to identify superparamagnetic macrophages—immune cells responsible for the degradation of erythrocytes—which accumulate iron. Experimental depletion of these macrophages resulted in a significant diminution of orientation capabilities when visual and solar cues were unavailable due to overcast conditions. This suggests a dual-system navigational framework where solar-based orientation remains primary, but magnetic sensing via the liver provides essential redundancy.

由波昂大學與馬克斯·普朗克動物行為研究所進行並發表於《科學》雜誌的最新研究表明，肝臟是磁覺感應的關鍵部位。研究人員利用形態學與基因組分析，鑑定出超常磁性巨噬細胞——這是一種負責分解紅血球並積聚鐵質的免疫細胞。實驗顯示，在陰天缺乏視覺與太陽線索的情況下，清除這些巨噬細胞會導致方向感顯著下降。這表明一種雙系統導航框架：基於太陽的方向感仍為主導，但透過肝臟的磁感應提供了必要的備援。

It is postulated that the proximity of these iron-rich macrophages to hepatic nerve fibers facilitates the transmission of magnetoreceptive data to the brain. While the study indicates a strong magnetic signal within the liver, external analysts suggest that the navigational process may be multifaceted, potentially involving other iron-storing organs such as the spleen or beak. Consequently, the possibility exists that the species employs a diversified array of magnetoreceptive mechanisms depending on the specific navigational requirement.

研究推測，這些富含鐵質的巨噬細胞與肝神經纖維鄰近，有利於將磁感應數據傳輸至大腦。雖然研究指出肝臟內存在強烈的磁信號，但外部分析人士認為，導航過程可能是多方面的，可能涉及其他儲鐵器官，如脾臟或喙。因此，該物種可能會根據特定的導航需求，採用多樣化的磁感應機制。

The study concludes that hepatic immune cells are necessary for magnetic orientation in pigeons, though further research is required to map the exact neural pathways to the brain.

研究結論指出肝臟免疫細胞對於鴿子的磁導航至關重要，但仍需進一步研究以繪製通往大腦的精確神經路徑。