Tue, Jun 03, 2008 - Page 13 News List

Scientists argue over mega-rat 巨鼠體型知多少?

In this undated photo scientist Martua Sinaga holds a 1.4kg giant rat found in the Foja Mountains of Indonesia. The giant rat is a species that's probably new to science.
在這張未註明日期的照片中,科學家馬圖亞.席納加手抱一隻重一點四公斤的巨鼠。這隻在印尼佛亞山區發現的巨鼠對科學界來說,可能是新物種。照片:美聯社

PHOTO: AP

Scientists are arguing about exactly how big the mightiest rodent to walk the Earth was.

The rat-like beast is dubbed Josephoartigasia monesi. It leapt into the headlines in January when Uruguayan experts said it weighed just over a tonne.

Their estimates were based on a massive skull found on a beach in Uruguay’s River Plate region. The skull was dated to some four million years ago.

The fossil measures 53cm and has gigantic teeth several centimeters long.

But if Virginie Millien of McGill University, Montreal, is right, J. monesi’s estimated mega-size is horribly wrong.

She wrote an article last month in the British journal Proceedings of the Royal Society. In the article Millien said the authors were wrong to try to calculate J. monesi’s body mass by drawing a comparison with rodents alive today.

According to Millien’s calculation's, J. monesi was “certainly the largest rodent ever described” but weighed in at no more than 350kg. That would make it about as big as a medium-sized horse.

By comparison, the biggest rodent alive today is the capybara, which can reach 60kg.

Despite its terrifying teeth, the creature was a peaceable herbivore that ate aquatic plants.

(STAFF WRITER, WITH AFP)

科學家們為了過去地球上,最大的齧齒類動物到底有多大而爭辯不休。

這種像鼠類的巨獸被命名為「莫尼西」。今年一月,烏拉圭的專家們表示莫尼西的體重超過一公噸後,牠立刻登上報紙頭條。

烏拉圭的專家以在河床區海灘發現的一個巨大頭蓋骨做為推論基礎,這個頭蓋骨約有四百萬年的歷史。

這塊化石長五十三公分,而且上面的巨齒就有好幾公分長。

但如果蒙特婁麥基爾大學的薇姬妮.米蓮推論正確的話,「莫西尼」的巨大體型就被錯估得離譜了。

她上個月在《英國皇家學會學報》期刊發表的一篇文章中提到,烏拉圭專家不應該拿現代齧齒動物的體型來做比較、推論「莫西尼」的身軀大小。

根據米蓮的估算,莫西尼「絕對是有史以來體積最大的齧齒類動物」,但牠的體重不會超過三百五十公斤。這樣算起來,牠的體型大概和一隻中型馬差不多。

比較起來,當今最大的齧齒類動物是體重可達六十公斤的南美無尾大水鼠。

儘管有著恐怖的牙齒,這種大水鼠卻是以水草為食的溫和素食主義者。

(法新社�翻譯:袁星塵)

TODAY'S WORDS 今日單字

1. rodent n.

齧齒目動物 (nie4 chi3 mu4 dong4 wu4)

例: The farmer has a lot of rodents in his barn.

(這個農夫在穀倉裡養了很多齧齒類動物。)

 

2. estimate v.t.

估計 (gu1 ji4)

例: We're trying to estimate the damage.

(我們正在估計損失。)

 

3. calculation n.

推測 (tui1 ce4)

例: Jimmie's calculation was way off.

(吉米估計的結果還差得遠呢。)

 

4. herbivore n.

草食性動物 (cao3 shi2 xing4 dong4 wu4)

例: Deer are herbivores.

(鹿是草食性動物。)


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