藍鯨在潛水覓食時，心臟每分鐘只跳動兩次

藍鯨在潛水覓食時，心臟每分鐘只跳動兩次

Blue whales are the largest animals that have ever lived on Earth. They can stretch up to 100 feet (30 meters) long and weigh 300,000 pounds (136 metric tons), roughly four times the length and 20 times the weight of an African elephant. They also have the biggest hearts in the animal kingdom — about the size of a bumper car, and weighing some 400 pounds (180 kilograms).

藍鯨是地球上曾經(jīng)生活過的最大的動物。它們可以長到100英尺(30米)，重達30萬磅(136噸)，大約是非洲象的4倍長，20倍重。它們的心臟在動物王國里也是最大的——大約一輛碰碰車那么大，重約400磅(180公斤)。

Photo: wildestanimal/Shutterstock

Until now, no one had managed to record the heart rate of a blue whale. That's understandable, given the logistical difficulties of measuring such a huge animal's pulse while it swims in the open ocean. Thanks to a team of U.S. researchers, though, we not only have the first recording of a blue whale's heart rate, but we also get to see how it changes as the whale dives to feed, going as deep as 600 feet (180 meters) for as long as 16 minutes at a time.

到目前為止，還沒有人能夠記錄到藍鯨的心率。這是可以理解的，考慮到在開放的海洋中測量這么大的動物的脈搏的后勤困難。不過，多虧了美國的一組研究人員，我們不僅首次記錄了藍鯨的心率，而且我們還可以看到它是如何變化的，因為鯨魚潛水覓食，深度高達600。英尺(180米)長達16分鐘。

Led by Jeremy Goldbogen, assistant professor of biology at Stanford University, the team used a specialized tracking device equipped with electrodes and other sensors, which they attached via suction cups to a wild blue whale in Monterey Bay, California. Their findings were published Nov. 25 in the Proceedings of the National Academy of Sciences.

在斯坦福大學生物學助理教授杰里米·戈德伯根的帶領下，研究小組使用了一種配備了電極和其他傳感器的專門追蹤裝置，通過吸盤將它們附著在加利福尼亞州蒙特利灣的一頭野生藍鯨身上。他們的發(fā)現(xiàn)發(fā)表在11月25日的《美國國家科學院院刊》上。

"The largest animals of all time, of course, can't be in the laboratory in a building," Goldbogen says in a video about the new study. "So we are bringing the biomechanics lab into the open ocean using these suction-cup attach tags."

“有史以來最大的動物當然不可能在實驗室里，”Goldbogen在一段關于這項新研究的視頻中說。“因此，我們將利用吸盤附加標簽把生物力學實驗室引入海洋。”

The data show how a blue whale's heart helps it perform its deep feeding dives, the researchers report, and they also suggest this enormous organ is operating near its limits. This could help explain why no animal has evolved to grow larger than a blue whale, since the energy needs of a larger body might surpass what's biologically possible for a heart to accommodate.

研究人員報告說，這些數(shù)據(jù)顯示了藍鯨的心臟是如何幫助它進行深食潛水的，他們還指出，這個巨大的器官正在接近它的極限。這可能有助于解釋為什么沒有動物進化到比藍鯨更大，因為一個更大的身體所需要的能量可能超過心臟所能容納的限度。

When the whale dove to feed, its heart rate slowed to an average of about four to five beats per minute, the researchers found, with a low of two beats per minute. It rose as the whale lunged for prey at the deepest point of its dive, increasing by about 2.5 times the minimum rate, then slowly fell again. A final surge occurred as the whale returned to catch its breath at the surface, where the highest heart rates of 25 to 37 beats per minute were recorded.

研究人員發(fā)現(xiàn)，當鯨魚俯沖進食時，它的心率會減慢到平均每分鐘4到5次，最低為每分鐘2次。當鯨魚俯沖至最深處撲向獵物時，它的速度上升，大約是最低速度的2.5倍，然后再次緩慢下降。最后一次高潮出現(xiàn)在鯨魚返回海面呼吸的時候，那里記錄的最高心率為每分鐘25到37次。

As the planet's largest animal, blue whales have a lot to teach us about biomechanics in general. But they're also listed as Endangered by the International Union for Conservation of Nature, and since their gigantic bodies are so dependent on a large, consistent food supply, insights like this could be particularly valuable for protecting the species.

作為地球上最大的動物，藍鯨可以教給我們很多生物力學知識。但它們也被國際自然保護聯(lián)盟列為瀕危物種，由于它們龐大的身體依賴于大量穩(wěn)定的食物供應，這樣的發(fā)現(xiàn)對保護物種可能特別有價值。

"Animals that are operating at physiological extremes can help us understand biological limits to size," Goldbogen says in a press release. "They may also be particularly susceptible to changes in their environment that could affect their food supply. Therefore, these studies may have important implications for the conservation and management of endangered species like blue whales."

Goldbogen在一份新聞稿中說:“在生理極限下活動的動物可以幫助我們理解體型的生物學極限。”“他們也可能特別容易受到環(huán)境變化的影響，這可能會影響他們的食物供應。因此，這些研究對保護和管理藍鯨等瀕危物種可能具有重要意義。”

The researchers plan to add more features to their suction-cup tag for future studies, including an accelerometer to shed more light on how heart rate changes during various activities. They also hope to use the tag with humpbacks and other whales.

研究人員計劃在吸盤標簽上添加更多的功能，以用于未來的研究，其中包括一個加速計，以便更清楚地了解心率在各種活動中是如何變化的。他們還希望把這個標簽用在座頭鯨和其他鯨魚身上。

"A lot of what we do involves new technology and a lot of it relies on new ideas, new methods and new approaches," says co-author and Stanford research assistant David Cade, who placed the tag on the whale. "We're always looking to push the boundaries of how we can learn about these animals."

“我們所做的很多事情都涉及到新技術(shù)，其中很多都依賴于新思想、新途徑和新方法，”合著者、斯坦福大學研究助理大衛(wèi)·凱德說。“我們一直在努力突破我們了解這些動物的極限。”