Birds of a feather flock together.”
Traditional saying
Within the last century, we have made great advancements in science and technology, from rockets to smart phones, but one of the most groundbreaking discoveries is the unraveling of the genome – DNA. As we mentioned earlier, DNA holds the information that makes a creature what it is – why a pigeon is a pigeon and not an eagle (even if it is having delusions of grandeur). Scientists can use your DNA to tell many things about you: whether you are a boy or a girl, where your family comes from, whether you are lactose intolerant, and much more. This is the purview of a field of science known as genetics.
One amazing thing that our genes is that they can even tell us who we are related to, who our parents, brothers, sisters, aunts, and uncles are. This might not seem so exciting to those of you who see your family all the time, but some people are not so lucky. For some, they lost touch with their biological family years ago, often through adoption. These people have the chance now to meet their family of origin and learn a bit more about where they come from.
Scientists are also using genetics to learn more about animals and who they are related to, a field of study known as cladistics. Our window into the world of genetic information has found some surprising things. For years, scientists were certain that the mostly herbivorous giant panda was not really a bear like the ferocious grizzly bear, but rather more closely related to the similar-looking red panda. Now we know they were completely incorrect: despite their largely gentle demeanor, pandas are bears, while the red panda is in a family all its own.
Studying the genes of animals have shown us that hyenas are actually in the cat family, despite their canine ears and behavior, while foosas (a cat-like predator of Madagascar) are really more like mongooses. Seals and walruses are in the same family as wolves and weasels, while manatees and dugongs are separated from their fellow marine mammals.
Cladistics hasn’t totally upended everything that we understood about how animals are related; it has also supported many older hypotheses. One of the most fundamental differences among types of mammals are the way that they are born. Nearly all mammals are born live from their mothers, but five species buck this trend: the duck-billed platypus and the echidnas, known collectively as the monotremes. These unusual (but quite cute) creatures are mammals that lay eggs and are only found on the continent of Australia. After the hatch the puggles (is there possibly a cuter name for a baby animal?) will stay with the mother for a time to feed on her milk just like other mammals.
Most mammals are born relatively developed, such as horses that can walk soon after birth and puppies that are covered with soft fur, but there is another group of mammals whose babies are born being relatively undeveloped: the marsupials. Kangaroos, wallabies, and opossums are members of this group, found only in Australia and North and South America. Soon after their jellybean-sized babies are born, they crawl into their mother’s pouch to nurse on her milk; they continue to grow in the warm, safe environment until they are big enough to venture into the wide world.