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Do rhesus monkeys have amniotic sacs?
Rhesus monkeys, like all primates belong to the placental group of mammals. They give birth to live young which are nourished before birth by the placenta and protected by the amniotic sac.
What are the characteristic of placental animals?
Some common characteristics unique to placental mammals are: 1. The young are nourished in a placenta before birth. 2. There are no epipubic bones. 3. Different openings are used for urination and defecation. 4. There is a malleolus (bony extension) at the bottom of the tibia. 5. The back bones of the foot fit into a hole fored by the bottom of the tibia and fibula. 6. The back of the first metatarsal bone is further back than the back of the second metatarsal bone. 7. A corpus callosum is present in the brain.
Where do placental mammals live?
Placental mammals are mammals that give birth to fully developed live young, such as like humans, for instance. They are classed within the group of animals known as eutherians. Dogs, cats, livestock, rodents, giraffes, rhinoceroses, etc, are all placental mammals. This is opposed to the monotremes, which are egg-laying mammals (platypuses and echidnas) or marsupials (kangaroos, koalas, wombats, etc), which give birth to very undeveloped young that must complete their development attached to a nutrient-supplying teat, usually in the mother's pouch.
How do developing placental young receive nourishment?
Before birth, nutrients in the mother's blood stream flow through the umbilical cord into the fetus's blood stream. After birth, young placental mammals suckle (drink their mother's milk) until they are weaned.
What is an organ in most mammals that provides nourishment to the young before birth?
The placenta. Placentas are found in female placental mammals (most mammals are placental mammals) inside the uterus and are a passageway by which nutrients flow from the mother's bloodstream to the baby's bloodstream and by which waste products flow from the baby's bloodstream to the mother's bloodstream.
Do mammals develop in egg or in uterus?
Placental mammals and marsupials develop in a placenta within the uterus before being delivered. Monotremes develop in an egg.
Why are plancetals more successful than marsupials and monotremes?
Because placentals are the largest number of mammals.
Where do most mammals grow before they're born?
Most mammals are placental mammals: they develop in a placenta before birth. Marsupials also develop in a placenta, but they are delivered much earlier and the placenta is less developed. Monotremes develop within an egg, which is kept inside the mother for some time before it is laid. It hatches several days later.
What are the common characteristics of placental?
Some common characteristics unique to placental mammals are: 1. The young are nourished in a placenta before birth. 2. There are no epipubic bones. 3. Different openings are used for urination and defecation. 4. There is a malleolus (bony extension) at the bottom of the tibia. 5. The back bones of the foot fit into a hole fored by the bottom of the tibia and fibula. 6. The back of the first metatarsal bone is further back than the back of the second metatarsal bone. 7. A corpus callosum is present in the brain.
Do rabbit have belly button?
All mammal's are connected to their mothers with an umbilical chord before they are born which is disconnected when they are born, so yes they do whether you can find it or not.
Why do kangaroos give birth to their young even before they are fully developed?
This feature is not restricted to kangaros. It is characteristic of all marsupials. The pouch serves a similar purpose to the uterus in placental mammals.
What are the key differences in reproductive strategies of marsupials compared with that of placental mammals?
1. Marsupials give birth to undeveloped young after a shorter gestation period (depending on the size of the animal); placental mammals give birth to more fully developed young.2. Marsupials' placentas are not as advanced as placental mammals' placentas.3. Marsupials' young must attach to the nipple for many weeks to several months before they are developed enough to detach; placental mammals' young do not need to attach permanently to the nipple for any period of time.4. Most marsupials have pouches in which they carry their young; no placental mammals have pouches.5. Most male marsupials (with the exception of the largest species of angaroos) have a "bifurcated" or two-headed penis which is only used for reproduction; male placental mammals have a one-headed penis which is also used for urination.6. Female marsupials have two vaginas, or what are called paired lateral vaginae. These are for the purpose of transporting the sperm to the womb, but there is a midline pseudovaginal canal for actually giving birth. As well as two vaginas and two uteruses, female marsupials have two fallopian tubes and two cervixes.
