This month, Smithsonian published a fascinating article about the history of chickens and how they basically took over the world. Obviously, chickens couldn't have established their empire without reproduction, so I thought I'd take a behind-the-scenes look at how chickens became so prominent. As it turns out, chicken procreation is a lot weirder than I thought. Here are just a few of the finer points. 1) Asymmetrical gonads Here's how gonads are usually arranged: males have two testes, and females have two ovaries. Both genders usually have one gonad on the right side of their body and one on the left. It's pretty simple. In contrast, hens only have one functional ovary. In fact, most birds have this lopsided anatomy probably because it's more practical for flight. Birds need to be light and compact in order to fly, so they only develop one of their gonads. For most male birds, the right testes is also smaller than the left. This trend do
A Breech Birth is when a baby is born bottom first instead of head first. Around 3-5% of pregnant women at term (37–40 weeks pregnant) have a breech baby. Most babies in the breech position are born by a caesarean section because it is seen as safer than being born vaginally. [1] Doctors and midwives in the developing world have thus lost many of the skills required to safely assist women giving birth to a breech baby vaginally. Delivering all breech babies by caesarean section in developing countries is difficult to implement as there are not always resources available to provide this service. Cause Edit With regard to the fetal presentation during pregnancy, three periods have been distinguished. During the first period, which lasts until the 24th gestational week, the incidence of a longitudinal lie increases, with equal proportions of breech or cephalic presentations from this lie. This period is characterized by frequent changes of presentations. The fetuses in