The earliest direct evidence for true mammalian life lies in a single fossilized brain case, found in China and described by Zhe-Xi Luo and Ai-Lin Sun in the 2001 issue of Science. The find, named Hadrocodium wui, dates to around 195 million years ago, placing the origin of true mammals sometime before the early Jurassic Period and perhaps even the late Triassic Period.
Mammals didn't "evolve" because there is no such thing as evolution. God created all living things. Granted, things have changed from the "beginning of time," but we did not start from a monkey or whatever they say these days.. Adam and Eve were the first humans, according to The Bible. All animals were created after them, but not from them.
If we are picky about which organisms count as true mammals, then mammals first came into existence in the early Jurassic. Mammal-like organisms, which had been becoming more and more like modern mammals, had existed before. Cynodonts, an early ancestor of mammals, arose before the Triassic, in the Permian.
The era that mammals became common would be the Cenozoic era.
around 250 million years ago
200 m.y.a. (million years ago)
The Cenozoic Era.
Gestation.
Placental mammals and marsupials develop in a placenta within the uterus before being delivered. Monotremes develop in an egg.
All mammals present today are example of tertiary period mammals as we are living in tertiary period .
The gestational period for a mammal varies. Smaller mammals tend to have a shorter gestational period than larger mammals.
They did not. Mammals evolved independently of birds.
chicken
yes. there mammals.
fluuckck you science
you can develop breasts before you begin your period. however it is more common to develop them after.
they are mammals,PERIOD.
Mammals faced a series of ice ages.
Horses are like most mammals (humans, too) and the unborn develop in a uterus.