Atrial fibrillation (AF or A-fib) is an abnormal heart rhythm characterized by rapid and irregular beating.
Emperor penguins owe their scientific name (Aptenodytes forsteri) to their discoverer, the first natural scientist to reach Antarctica, the German Johann Reinhold Forster. Forster came to Antarctica in 1770, on Captain James Cook's ship, and saved Cook's life during the voyage.
The Humboldt penguin, Spheniscus humboldti, lives on the coasts of Peru and Chile and islands off western South America. Like most Spheniscus penguins, these birds grow to a height of around 2 feet and weigh 9 pounds. Humboldt penguins breed in climates ranging from arid to hot and humid.