Pregnancy is a significant time in the life of animals. Full-fledged bearing and timely delivery are the key to healthy and competitive offspring.
Instructions
Step 1
Pregnancy of mammals is divided into several stages: fertilization - the fusion of the male sperm with the female ovum, the penetration of the fertilized cell into the muscle sac - the uterus, development of the fetus. The logical conclusion of pregnancy is childbirth.
Step 2
Depending on the number of offspring, singleton and multiple pregnancies are distinguished. Here indicators vary from species to species. So, on average, 2-20 cubs are born in predators, in ungulates 1-2, in rodents 2-10, in bats 1-2 cubs in a litter.
Step 3
The duration of pregnancy in most cases depends on the size of the animal. A huge elephant bears a fetus for 20-22 months, a rhinoceros - 15, a hippopotamus - 8, a cow - 9, a horse - 11, a lion - 3, 5, a dog - 2. Pregnancy of smaller animals is calculated in days: a hedgehog and a ferret - 40, a mouse - 21, columns - 28. But this pattern has exceptions. In marten, ermine and sable, the time from conception to delivery is 9-10 months. This period is explained by the fact that the fertilized egg does not develop immediately after conception, but waits for favorable conditions.
Step 4
Marsupials have a very short gestation period, because the fetus is not associated with the mother's body, but receives nutrition from the yolk bladder. The emerging cub is more like an embryo: pink transparent skin, no hair. It continues its development in the brood pouch, feeding on the mother's milk. A baby kangaroo spends only 35 days in the womb, and lives in a pouch for up to eight months.
Step 5
Childbirth in animals lasts up to several hours. After birth, the female cleans the mouth and nostrils of the baby from mucus, licks it. How developed and independent a cub will be born depends on the habitat.
Step 6
The longest pregnancy is in the black alpine salamander (31 months), the shortest is in the North American possum (8 days). The most developed cubs are born to elephants and ungulates, the most helpless - to marsupials. The largest broods are found in rodents and predators (up to 20), the smallest in elephants and whales (1).
Step 7
A baby elephant is born with five centimeter milk tusks. The kitten is born weighing up to 800 kg and up to 5.5 meters long, drinking up to 380 liters of milk daily. Immediately after birth, the female brings it to the surface for independent inhalation. A normal pig pregnancy lasts 3 days, 3 weeks and 3 months, giving birth up to 6 hours. Blind cubs of marsupials reach the female's mammary glands in minutes. Cats, dogs, foxes and wolves, thanks to common ancestors, have an equal gestation period (2 months).
