与其他phocids物种（如灰海豹）相比，港海豹体型较小。众所周知，灰海豹在整个哺乳期都禁食。
Harbor seals are small compared with other phocids species such as grey seals, all of which are known to fast for the entire lactation period.
它们的身体呈流线型，后肢完全消失，身体上长出了尾片和喷水孔，所有这些特征都无法掩饰它们与陆生哺乳动物之间的亲缘关系。
Their streamlined bodies, the absence of hind legs, and the presence of a fluke and blowhole cannot disguise their affinities with land dwelling mammals.
据称,从蠕虫动物到哺乳动物都适用于此说法.
That has been demonstrated in creatures ranging from worms to mammals.
在他看来，在白垩纪虱子物种进化时的宿主可能是哺乳动物系统树上的另一分支而这一分支上的所有物种都灭绝了。
In his view, the hosts on which lice were speciating during the Cretaceous could have been a different branch of the mammalian family tree, all of whose species are extinct.
这些情绪，包括大脑边缘系统，是所有的哺乳动物都具有的。
These emotions—along with the limbic system—are shared by all mammals.
它与其他哺乳动物有超过80%的基因都相同。
It shares more than 80 percent of its genes with other mammals.
一项研究发现，过去几个世纪已经宣告灭绝的哺乳动物中有三分之一其实都活得好好的。
A study has found that a third of all mammal species declared extinct in the past few centuries have turned up alive and well.
从第一只动物到其逐渐进化而成的后裔，如鸟、爬行动物和哺乳动物，都把抚养后代视为头等大事，它们为年轻的下一代殚心竭虑，关怀备至，操碎了心；
Those other first animals tended to their young, as do most of their descendants, such as birds, reptiles, and mammals, which still bring their young food and fight to protect them.
约有20%的海生群落以及多数类似哺乳类的生物，很多大型的两栖动物，和所有的非恐龙的祖龙都灭绝了。
About 20 percent of all Marine families went extinct, as well as most mammal-like creatures, many large amphibians, and all non-dinosaur archosaurs.
几乎自然界中所有的物种，从单细胞生物到哺乳动物(包括人类)，都具有一种日常活动周期，称为昼夜节律。
Virtually all species in nature, from single-cell organisms to mammals, including humans, exhibit a daily cycle of activity called circadian rhythm.
但是，由于在陆地上不需要这样的电子磁场探测系统，爬行类动物，鸟类和哺乳动物都渐渐失去了这一功能。
However, over the years reptiles, birds and mammals lost their electrosense as it wasn’t needed for life on terra firma.
海豚、鲸鱼以及水生哺乳动物睡眠都极少，这一事实可以给睡眠的根本功能提供有用的线索。
Perhaps one useful hint about the original function of sleep is to be found in the fact that dolphins and whales and aquatic mammals in general seem to sleep very little.
几世纪以来生物学家都知道鸟类的骨头又细又空，但鸟类的骨架并不比相同体积的哺乳动物的轻。
For centuries, biologists have known that bird bones are thin and hollow. Yet bird skeletons don't actually weigh any less than the skeletons of similarly sized mammals.
“控制热量”从线虫类动物到哺乳动物（包括人类）的一切生物都起作用，这在整个行业中已经众所皆知。
“Caloric restriction”, as it is known in the trade, works for everything from threadworms to mammals (people included, as far as can be ascertained without the luxury of controlled experiments).
根据国际自然与自然资源保护联合会公布的哺乳动物《红色名单》显示，婆罗洲猩猩和苏门答腊猩猩都属于濒危动物。
Both the Borneo and Sumatran species of orangutans are endangered, according to the IUCN red List of mammals.
刺激哺乳动物的外侧下丘脑会让他们陷入一种循环，Panksepp写道，“每次刺激都唤起新的搜索策略。”(Panksepp没有提到Bing)。
Mammals stimulating the lateral hypothalamus seem to be caught in a loop, Panksepp writes, "where each stimulation evoked a reinvigorated search strategy" (and Panksepp wasn't referring to Bing).
所有动物都具有令人惊讶的特质，但我认为真正的区别在于我们从未有过哺乳动物。
All of which have incredible qualities and the real distinctive feature I suppose is that we'd never got mammals.
这些情绪，包括大脑边缘系统，是所有的哺乳动物都具有的。
These emotions - along with the limbic system - are Shared by all mammals.
不像其他有蹄子的哺乳动物，斑马和其他马科动物的每只脚上都只有一个脚趾。
Unlike other hoofed mammals, zebras and their horse relatives have only one toe on each foot.
然而他们从小一起长大，由于两人都自小没有母亲，甚至还由同一个奶妈哺乳。
However, they grew up together, because the two people are being no mother, even by the same mammy lactation.
我们都知道大象是最大的陆生哺乳动物，也许还是食量最大的动物。
As we all know, the elephant is largest land mammal, and perhaps the heaviest of eaters.
尽最大努力在哺乳之初让一切都顺利进行，对于重返职场后能够继续母乳喂养是非常重要的。
The longer you can enjoy this exclusive breastfeeding relationship, the easier it will be to continue when you are back on the job.
我通过看书知道大多数哺乳动物都生活在陆地上。
尽最大努力在哺乳之初让一切都顺利进行，对于重返职场后能够继续母乳喂养是非常重要的。
Doing everything you can to make breastfeeding work well in the early weeks is important to breastfeeding success after you return to work.
如果将情绪定义为引发动机的感觉，那所有哺乳动物都算得上有情绪。
As such, all mammals have emotions, defined as sensations that provoke motivations.
他们的结果证明，在现生哺乳类中，鲸豚与偶蹄类最亲近；骆驼、河马、猪及牛羊等反刍动物都属于偶蹄类。
Experts agree that hippos belong to the mammalian order artiodactyla, a group of even - toed, hoofed creatures whose extant representatives include camels, pigs and ruminants such as cows.
每一种哺乳动物、鸟类和大多数爬行动物、两栖类动物和鱼类都需要睡眠来维持正常的生命活动。
Each kind of mammals, birds and most reptiles, amphibians animals and fish are in need of sleep to maintain normal life activities.
每一种哺乳动物、鸟类和大多数爬行动物、两栖类动物和鱼类都需要睡眠来维持正常的生命活动。
Each kind of mammals, birds and most reptiles, amphibians animals and fish are in need of sleep to maintain normal life activities.
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