Whales, as rare mammals that have returned to the sea from land, have completely disappeared from the body of mammals in appearance, looking like a big fish, and in ancient times people defined whales as fish, until Darwin observed bears swimming in the water for several hours, and he for the first time made a reverse guess about the connection between terrestrial mammals and marine animals.
He wrote in the 1859 edition of The Origin of Species: "We can see that through natural selection, the bear's body structure and habits will become more and more adapted to aquatic life, and the mouth will become larger and larger, and it is possible that in the future it will evolve into a whale-like aquatic animal." But this text was condemned and ridiculed by public opinion at the time, and Darwin deleted this passage in a later version, but he did not change this speculation privately, and to this day, primary school students know that whales evolve from terrestrial to aquatic, which has become common sense, and this common sense is inseparable from the efforts of great biologists such as Darwin in the old days to break the fixed thinking.
As a mammal, the appearance and signs of a whale are very different from those of ordinary mammals, and people may wonder, where are its mammalian organs? How do I breastfeed?
On the surface of the whale's body, there are indeed no mammalian organs, that is because the mammalian organs are contracted in the skin of the whale, and under the abdomen of the mother whale, there is a long fissure, which is the reproductive fissure used by the mother whale to produce young children, and on both sides of this reproductive fissure, there are two short breast milk fissures, and the nursing organs are hidden in it.
Genital cleft and breast milk cleft
Contrast of the fissures in the abdomen of male and female whales
When the toddler is hungry, it will swim to the bottom of the mother whale's abdomen, the mother whale will stop, sometimes for convenience, will also flip the body over, the toddler with the mouth into the crack, bite the female whale's nursing organs, at this time the whale's breastfeeding process, not like the general mammal, is taken by the toddler to actively ingest, but by the female whale to spray whale milk into the mouth of the young child.
Female whales breastfeed young children
The whole process time is very short, only a short less than twenty seconds, but even in such a short period of time, the mother whale once sprayed to the toddler's breast milk, has reached 10 liters, small and medium-sized whale children a day the need for breast milk will not be too much, generally dozens of liters, but such a large animal as the blue whale, its young children need up to 400 liters of breast milk a day, converted into the 2 liters of mineral water we usually buy, blue whale children need to drink the equivalent of 200 bottles of mineral water a day.
And whale milk and the general mammal is not the same, not liquid, but semi-liquid semi-coagulated, a bit like diluted toothpaste, this is because the nutritional structure of whale milk, the content of fat more than 50%, whale children eat can quickly gain weight, such as humpback whale children in sufficient nutrition conditions, a day weight gain of up to 80 pounds to 100 pounds.
Whale milk
Someone on the Internet asked, so can whale milk be eaten by humans like cow's milk and goat's milk? In theory, sterilization can be drunk by humans, but in fact, no one has promoted whale milk, because the collection cost is too large, and there is no current market demand, some researchers have tried whale milk, according to them, whale milk has a strong fishy smell.
Whales although the way of breastfeeding is unique, but also its evolution from land animals to aquatic animals to make adaptive changes, whales are very focused on the growth of young children, such as humpback whales, in order to breastfeed young children, it does not eat for a long time or even up to several months, until the end of the lactation period, only began to look for food, so the whale's parent-child relationship is usually very close, scientific observers often see whale mother and child warm pulse swimming, which is a rare warm scene in the vast sea.