這只海豚媽媽收養(yǎng)了一個來自不同物種的嬰兒

這只海豚媽媽收養(yǎng)了一個來自不同物種的嬰兒

Bottlenose dolphin mothers typically raise one calf at a time, so researchers took notice when they saw a mother with two calves off the coast of Rangiroa Atoll in French Polynesia. Two calves aren't unheard of, but what really stood out was the difference between them. While one looked like a normal baby bottlenose dolphin, something was unusual about the other one.

寬吻海豚媽媽通常一次只喂養(yǎng)一頭幼崽，所以當(dāng)研究人員在法屬波利尼西亞的蘭吉羅阿環(huán)礁海岸看到一頭母海豚和兩只幼崽時，就注意到了這一點。兩只牛犢并不是聞所未聞，但真正引人注目的是它們之間的差異。其中一只看起來像一只正常的寬吻海豚寶寶，而另一只卻有些不同尋常。

Unlike a bottlenose dolphin's namesake snout, this calf had a blunter, rounder face. Led by Pamela Carzon of the Groupe d’Étude des Mammifères Marins (GEMM) de Polynésie, the researchers eventually realized the calf wasn't a bottlenose dolphin, but a baby melon-headed whale, as they report in the journal Ethology. That's not only a different species of dolphin, but a different genus.

與寬吻海豚不同，這只海豚的臉更粗更圓。在波利尼西哺乳動物研究小組的帕梅拉·卡松的帶領(lǐng)下，研究人員最終意識到，這頭小海豚不是寬吻海豚，而是一頭瓜頭小鯨魚，他們在《動物行為學(xué)》雜志上發(fā)表了研究報告。這不僅是不同種類的海豚，而且是一個不同的屬。

Photo: Pamela Carzon/Groupe d’Étude des Mammifères Marins

As Erica Tennenhouse reports for National Geographic, this is the first known case of a wild bottlenose mother adopting a calf of another species. And it may be just the second confirmed case of any wild mammal adopting a baby from outside its own genus. (Aside from humans, of course, who commonly adopt dogs, cats and other nonhuman mammals as pets.)

據(jù)艾麗卡·坦南豪斯為《國家地理》雜志報道，這是已知的第一例野生寬吻海豚媽媽收養(yǎng)另一物種幼崽的案例。這可能是第二例被證實的野生哺乳動物收養(yǎng)自己屬以外的嬰兒的案例。(當(dāng)然，除了人類。人類通常會收養(yǎng)狗、貓和其他非人類哺乳動物作為寵物。)

Wild mammals sometimes adopt unrelated babies from within their own species, but interspecies adoption is much less common, and cross-genus adoption is even rarer. Until now, the only scientifically documented case was from 2006, Tennenhouse notes, when a group of capuchin monkeys were reported to be raising a baby marmoset.

野生哺乳動物有時會從它們自己的物種中收養(yǎng)不相關(guān)的嬰兒，但跨物種收養(yǎng)就不那么常見了，跨屬收養(yǎng)就更少了。Tennenhouse指出，到目前為止，唯一有科學(xué)記載的案例發(fā)生在2006年，當(dāng)時有報道稱一群卷尾猴正在撫養(yǎng)一只小狨猴。

This photo shows the bottlenose mom with her biological daughter (left) and adopted son (top), a melon-headed whale. (Photo: Pamela Carzon/Groupe d’Étude des Mammifères Marins)

In this new case, the bottlenose mom already had a young calf — presumably her biological daughter — when she took in the melon-headed whale. That's an extra burden for a species that usually raises one calf at a time, although the researchers think the first calf might have actually made the mother more open to adopting the second.

在這個新案例中，寬吻海豚媽媽在收養(yǎng)這頭瓜頭鯨時，已經(jīng)有了一只幼崽——可能是她的親生女兒。對于一個通常一次只養(yǎng)一個幼崽的物種來說，這是一個額外的負(fù)擔(dān)，盡管研究人員認(rèn)為，第一頭“小牛”實際上可能會讓母親更愿意收養(yǎng)第二頭“小牛”。

Carzon and her colleagues have been conducting a long-term study of this bottlenose community since 2009. The melon-headed calf first showed up in 2014, when he was about a month old, and quickly grew inseparable from his new mother. Her own daughter had been born the same year, and the trio became a common sight as they swam around the area together. (There was a little sibling rivalry, though, as the adopted calf jockeyed with his sister for a swimming position underneath their mother.)

Carzon和她的同事從2009年開始就對寬吻海豚進(jìn)行了長期的研究。這頭瓜頭小鯨魚首次出現(xiàn)在2014年，當(dāng)時它大約一個月大，很快就和它的新媽媽形影不離了。它自己的女兒也是在同一年出生的，當(dāng)它們一起在這片海域游泳時，這三個人就成了一道常見的風(fēng)景。(不過，當(dāng)這只被收養(yǎng)的小鯨魚和妹妹爭奪媽媽身下的游泳位置時，它們之間有了一場小小的兄弟姐妹間的競爭。)

This family of three lived together for about a year and a half, until the biological daughter disappeared for unknown reasons. It's possible something bad happened to her, although as Meilan Solly notes in Smithsonian Magazine, she might have just moved on to a different social subgroup. The adopted son, however, remained with his mother until April 2018. That's nearly three years after she adopted him, and it's around the age when many bottlenose dolphin calves wean.

這個三口之家在一起生活了大約一年半，直到親生女兒不知何故失蹤。也許它發(fā)生了什么不好的事情，盡管正如美蘭·索利在《史密森雜志》上所指出的，它可能只是換了一個不同的社會亞群體。然而，這個養(yǎng)子直到2018年4月才離開母親。那是在它收養(yǎng)它將近三年之后，也就是許多寬吻海豚幼崽斷奶的時候。