African penguin embryos rely entirely on the contents of the egg to develop. The yolk has the required sugars, fats and cholesterol. The extensive blood vessels that are found throughout the egg move the nutrients to the embryo. After only 10-14 days the embryo is easy to recognize; the eyes are very large early on. Tail feathers are seen early in the second trimester. Oxygen and carbon dioxide are transported through microscopic pores in the egg shell. The egg shell forms a high proportion of the egg weight which may be related to the fact that many penguin species utilize very little nest material. By Day 32-35 the chick is so large in the egg that an egg candler only shows a very dark, full embryo. In order for the staff to determine viability of the embryo we utilize a digital heart rate monitor called an Egg Buddy. The Buddy shows the chick’s heart rate in BPM (Beats Per Minute).-Pamela Schaller