Everyone knows about mammals from the school curriculum. Did you know that an egg-laying mammal is a separate animal species that lives only on the territory of one continent - Australia? Let's take a closer look at this special kind of animal.
Opening oviparous
For a long time, the existence of unique animals that breed by incubating eggs was not known. The first message about these creatures came to Europe in the 17th century. At this time, the skin of a marvelous creature with a beak, covered with wool, was brought from Australia. It was a platypus. The alcoholized copy was brought only 100 years later. The fact is that platypuses practically do not tolerate captivity. It is very difficult for them to create conditions during transportation. Therefore, they were observed only in their natural environment.
Following the discovery of the platypus, news came of another creature with a beak, only now covered in quills. This is an echidna. For a long time, scientists argued about which class to classify these two creatures. And they came to the conclusion that the platypus and echidna, egg-laying mammals, should be placed in a separate detachment. So the squad was bornSingle pass, or cloacal.
Amazing platypus
A unique creature of its kind, leading a nocturnal lifestyle. The platypus is distributed only in Australia and Tasmania. The animal lives half in the water, that is, it builds holes with access to the water and to land, and also feeds in the water. A creature of small size - up to 40 centimeters. It has, as already mentioned, a duck nose, but at the same time it is soft and covered with skin. Only in appearance it is very similar to a duck. There is also a 15 cm tail, similar to a beaver's tail. The paws are webbed, but at the same time they do not interfere with the platypus walking on the ground and excellent digging holes.
Since the genitourinary system and the intestines exit the animal in one hole, or cloaca, it was assigned to a separate species - cloacae. It is interesting that the platypus, unlike ordinary mammals, swims with the help of its front paws, and the hind legs serve as a rudder. Among other things, let's pay attention to how it reproduces.
Platypus reproduction
An interesting fact: before breeding, animals hibernate for 10 days, and only after that does the mating season begin. It lasts almost the entire autumn, from August to November. Platypuses mate in the water, and after a two-week period, the female lays an average of 2 eggs. Males do not participate in the later life of offspring.
The female builds a special hole (up to 15 meters long) with a nest at the end of the tunnel. Lines it with raw leaves and stems to maintain a certain humidity so that the eggs do not dry out. Interestingly, forprotection, she is also building a 15 cm thick barrier wall.
Only after the preparatory work, she lays eggs in the nest. The platypus incubates eggs by curling up around them. After 10 days, babies are born, naked and blind, like all mammals. The female feeds the babies with milk, which flows from the pores directly through the fur into the grooves and accumulates in them. Babies lick milk and thus feed. Feeding lasts about 4 months, and then the kids learn to get food on their own. It was the method of reproduction that gave this species the name "egg-laying mammal".
Extraordinary echidna
Echidna is also an egg-laying mammal. This is a land creature of small size, reaching up to 40 centimeters. It also lives in Australia, Tasmania and the islands of New Guinea. In appearance, this animal looks like a hedgehog, but with a long narrow beak, not exceeding 7.5 centimeters. Interestingly, the echidna has no teeth, and it catches prey with a long sticky tongue.
The body of the echidna is covered on the back and sides with spines, which were formed from coarse wool. Wool covers the belly, head and paws of the animal. Echidna is fully adapted for a certain type of food. It feeds on termites, ants and small insects. She leads a daytime lifestyle, although it is not easy to find her. The fact is that she has a low body temperature, up to 32 degrees, and this does not allow her to endure a decrease or increase in ambient temperature. In this case, the echidnabecomes lethargic and rests under trees or hibernates.
Echidna breeding method
Echidna is an egg-laying mammal, but it was only possible to prove this at the beginning of the 21st century. The mating games of echidnas are interesting. There are up to 10 males per female. When she decides she's ready to mate, she lays down on her back. At the same time, males dig a trench around it and begin to fight for supremacy. The one who turned out to be stronger copulates with the female.
Pregnancy lasts up to 28 days and ends with the appearance of one egg, which the female moves to the brood fold. It is still not clear how the female moves the egg into the bag, but after 10 days the baby appears. The baby comes into the world incomplete.
Cub
The birth of such a baby is very similar to the birth of young marsupials. They also pass their final development in the mother's pouch and leave her as adults, ready for independent life. Interesting fact: marsupials are also common only in Australia.
How does the echidna baby appear? He is blind and naked, his hind limbs are not developed, his eyes are covered with a leathery film, and fingers are formed only on the front paws. It takes a baby 4 hours to get to milk. Interestingly, in the mother's bag there are 100-150 pores that secrete milk through special hairs. The kid just needs to get to them.
The baby is in the bagmother for about 2 months. He gains weight very quickly due to nutritious milk. Echidna's milk is the only one that has a pink color due to the large amount of iron in it. Feeding continues until 6.5 months. After that, the young learn to get food on their own.
Trickster
Prochidna is another egg-laying mammal. This creature is much larger than its counterparts. The habitat is the north of New Guinea and the islands of Indonesia. The size of the prochidna is impressive, up to 80 centimeters, while its weight is up to 10 kilograms. It looks like a echidna, but the beak is much longer and the needles are much shorter. She lives in mountainous areas and feeds mostly on worms. The structure of the oral cavity of the prochidna is interesting: her tongue has denticles, and with the help of it she is able not only to chew food, but, as has been noted, even to turn over stones.
This species is the least studied, as it lives in the mountains. But at the same time, it was noticed that the animal does not lose mobility in any weather, does not hibernate and knows how to regulate its own body temperature. Reproduction of egg-laying mammals, which includes the prochidna, occurs in the same way as in the other two species. She hatches only one egg, which is placed in a bag on her stomach, and feeds the young with milk.
Comparative characteristics
And now let's look at the types of mammals that live on the Australian continent. So, what is the difference between oviparous, marsupials andplacental mammals? To begin with, it must be said that all mammals feed their offspring with milk. But the birth of babies has huge differences.
Egg-laying animals have one thing in common. They lay eggs like birds and incubate them for a certain amount of time. After the birth of the offspring, the mother's body produces milk, which the babies eat. It should be noted that the cubs do not suck milk, but lick it from the grooves on the female's stomach. The absence of nipples distinguishes oviparous from other mammals.
Marsupials have a brood pouch, hence their name. The pouch is located on the abdomen of females. A newborn baby, having reached it, finds a nipple and, as it were, hangs on it. The fact is that babies are born unformed and spend several more months in their mother's pouch until they are fully developed. It must be said that oviparous and marsupial mammals are similar in this respect. Echidna and prochidna babies are also born underdeveloped and placed in a kind of brood fold.
What about placental mammals? Their babies are born fully formed due to the presence of a placenta in the uterus. Due to it, the process of nutrition and development of the cub takes place. Most of the animals are placental.
This is the diversity of species on one continent.
