King penguins have such a long breeding cycle that it does not fit in a single year. The chick hatches in spring/summer and is well-fed by its parents until it reaches a size of 10-12kg, at which point winter arrives and the parents leave to feed at sea for three to four months. The chick loses about 70% of its body mass during this fast.
(image from wikipedia)
(submitted by fuckyeahbiomajorplanarian)