Penguins, seals, and whales have countercurrent heat exchangers to limit blood flow in certain areas of their body, limiting their rate of heat loss to their environment. In this homeostasis video, the instructor explains that homeostatic hugs are between tissues of an organism to allow for a stable internal environment. Scholars see how countercurrent heat exchange and close proximity between capillaries and alveoli allow humans to keep heat at their cores, maintain oxygen levels, and filter blood.