Wednesday, June 25, 2025

貓喜歡左側臥睡,是一種生存機制

貓每天平均睡眠12至16小時,不過很少有人觀察牠們的睡覺方式。最近一篇發表在Current Biology的研究分析了超過四百部的貓咪睡覺影片,發現大多數的貓喜歡左側臥睡,這可能是一種生存上的防禦機制。(全文在留言)

一項發表透過分析408支公開的YouTube貓咪睡覺影片,發現約有三分之二的家貓傾向於左側臥睡。這項結果揭示了一種精細的演化生存策略。貓每天平均睡眠12至16小時,等於牠們約60–65%的生命時間都處於極度脆弱的狀態,特別是在熟睡的深層睡眠階段。為了降低遭受掠食的風險,貓通常選擇在高處睡覺,這不僅能使掠食者較不易接近,也讓貓可以從高處監控周遭環境。這樣的行為已被視為一種防禦機制,而研究者認為,偏好左側臥睡的習性可能進一步強化這種生存上的優勢。

該研究特別挑選影片中單隻貓咪、全身可見且在單側保持至少10秒不間斷睡眠的片段,並排除畫質低、重複、鏡像或修改過的影片。結果顯示有266隻貓(占65.1%)採取左側睡姿,而只有142隻(34.8%)右側睡,顯示結果具有統計上的顯著性。研究者指出,當貓以左側臥睡時,醒來後左眼(即左側視野)首先接收外界資訊,而這部分的視覺輸入會直接送往大腦右半球處理。右腦擅長掌握空間資訊、辨識威脅與協調快速逃逸動作,因此這樣的神經迴路有利於貓在醒來後立即對潛在掠食者或獵物做出反應。

研究團隊也探討了其他可能的解釋,例如是否與懷孕或慣用爪有關。然而,由於資料來源未提供性別或懷孕狀態,且左右撇貓的分佈大致平均,因此無法支持這些因素與偏側睡姿的關聯。研究人員認為,這種偏側行為更可能反映出動物界普遍存在的左右腦功能不對稱現象,這種側化特性已在許多物種中被觀察到。腦半球的專業化可提升訊息處理效率、減少認知資源重複使用,並強化對環境刺激的即時反應能力。對於身兼掠食者與獵物角色的貓而言,這種神經與行為上的演化調整可能在危機時刻成為左右生死的關鍵。

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https://www.cell.com/current-biology/fulltext/S0960-9822(25)00507-X

Lateralized sleeping positions in domestic cats

Cover Image - Current Biology, Volume 35, Issue 12

Summary

Both vertebrates and invertebrates show a multitude of left–right asymmetries of brains and behaviors. For example, cats, dogs, and many other species have a preferred paw when handling food. But why should humans and other animals have lateralized brains? Based on a large comparative approach, it is likely that asymmetries serve several purposes. First, by specializing on one limb or one side of its sensory system, the contralateral hemisphere goes through life-long cycles of motor and perceptual learning, thereby increasing the speed of processing and motor efficacy, decreasing reaction time, and enhancing discrimination ability. Second, by having two complementary, specialized hemispheres, neural processes are computed in parallel, thereby reducing cognitive redundancy. For example, the right hemisphere excels in processing threat-related stimuli, providing the left visual field an advantage in reacting to a predator approaching from the left. Here, we report that two-thirds of cats prefer a leftward sleeping position, giving their left visual field and thus their right brain half a privileged view of approaching animals without being obstructed by their own body.



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