研究發(fā)現(xiàn),，相對于自身身體大小,，蜂鳥是世界上速度最快的脊椎動物。每秒鐘它們能夠比其他脊椎動物飛過更多的身體長度,。相對于自身的尺寸,，蜂鳥甚至比戰(zhàn)斗機(jī)和航天飛機(jī)都飛得快，而且能比戰(zhàn)斗機(jī)承受更大的地球引力影響,。
高速俯沖：蜂鳥求愛禮儀
加州大學(xué)伯克利分校的克里斯托弗-詹姆斯-克拉克是一名動物學(xué)家,，他對雄性蜂鳥俯沖進(jìn)行了高速拍照。他測量發(fā)現(xiàn),，蜂鳥每秒鐘飛行385個(gè)身體長度,，折合27.3米每秒,。這是記錄到的脊椎動物相對于身體的最高速度。相對于身體大小,，比蜂鳥運(yùn)動速度快的動物是一些昆蟲,，比如跳蚤。高速俯沖是雄性蜂鳥向雌性蜂鳥求愛的禮儀,。
“行為展示是動物求愛的常見現(xiàn)象”,，克拉克在今天的《皇家學(xué)會學(xué)報(bào)B》(Proceedings of the Royal Society B)上寫道。“僅僅是雌性的喜好就會導(dǎo)致雄性夸張的體征(比如雄性孔雀漂亮的尾巴),，雌性動物對雄性動態(tài)行為的喜好會導(dǎo)致雄性接近自己身體極限去完成高難動作,。”
承受9倍重力的俯沖
在俯沖時(shí)，蜂鳥會承受9倍重力的負(fù)荷,，這是記錄到的脊椎動物在飛行時(shí)承受的負(fù)荷的最大值,。而駕駛戰(zhàn)斗機(jī)的飛行員在承受7倍重力的負(fù)荷時(shí)，會短暫性眼前發(fā)黑,。俯沖飛行是許多鳥類求愛時(shí)喜歡用的動作,，比如夜鷹、沙錐鳥等等,。翠鳥和其他許多海鳥會借助俯沖來捕食,。俯沖會使鳥類獲得很高的速度?？死藢懙栏咚俑_是蜂鳥求愛中的關(guān)鍵環(huán)節(jié),，而且它還會把尾巴羽毛張開，因?yàn)檫@能產(chǎn)生巨大的短暫的聲響,，以引起雌性蜂鳥的注意和好感,。
蜂鳥的最大速度385身長/秒超過了捕食時(shí)游隼俯沖的最高速度200身長/秒和燕子的最高速度350身長/秒?？死诉€寫道,，蜂鳥的速度比速度最快的戰(zhàn)斗機(jī)和航天飛機(jī)都快。在后然器開啟的情況下,，戰(zhàn)斗機(jī)的最高速度可達(dá)150身長/秒,，航天飛機(jī)達(dá)到207身長/秒。不過戰(zhàn)斗機(jī)和航天飛機(jī)的絕對速度很大,，比如戰(zhàn)斗機(jī)可達(dá)每秒885米,，航天飛機(jī)達(dá)到每秒7700米。（生物谷Bioon.com）
生物谷推薦原始出處：
Proceedings of the Royal Society B June 10, 2009, doi: 10.1098/rspb.2009.0508
Courtship dives of Anna's hummingbird offer insights into flight performance limits
Christopher James Clark
Behavioural displays are a common feature of animal courtship. Just as female preferences can generate exaggerated male ornaments, female preferences for dynamic behaviours may cause males to perform courtship displays near intrinsic performance limits. I provide an example of an extreme display, the courtship dive of Anna's hummingbird (Calypte anna). Diving male Anna's hummingbirds were filmed with a combination of high-speed and conventional video cameras. After powering the initial stage of the dive by flapping, males folded their wings by their sides, at which point they reached an average maximum velocity of 385 body lengths s?1 (27.3 m s?1). This is the highest known length-specific velocity attained by any vertebrate. This velocity suggests their body drag coefficient is less than 0.3. They then spread their wings to pull up, and experienced centripetal accelerations nearly nine times greater than gravitational acceleration. This acceleration is the highest reported for any vertebrate undergoing a voluntary aerial manoeuvre, except jet fighter pilots. Stereotyped courtship behaviours offer several advantages for the study of extreme locomotor performance, and can be assessed in a natural context.
