: The most numerous of the placentals, ranging from tiny mice to flying insect-eaters. 4. Where Did We Come From?
The defining feature of this group is the placenta, a vascular organ that develops in the mother’s uterus during pregnancy. placental mammal
The Ultimate Insider: Why Placental Mammals Rule the Earth Take a look around. From the dog napping at your feet to the squirrels darting across the park—and even the person reading this—you are surrounded by . Also known as eutherians , this group represents over 90% of all mammal species on the planet. : The most numerous of the placentals, ranging
: This strategy is physically draining and risky for the mother, who becomes less mobile and must eat significantly more to support the growing fetus. 3. A Family Tree of Giants and Shrews The defining feature of this group is the
But what exactly makes us so special? It all comes down to a temporary, high-tech organ called the . 1. The Placenta: Nature’s Ultimate Life Support