1.   Other diving birds, including ocean-going penguin species in the southern hemisphere, can also sit out storms.

2.   The formula was clearly a successful one as proved by the high survival rate and healthy condition of all four penguin species.

3.   But new research on the largest penguin species, the emperor, shows that all the side-to-side movement actually helps the birds conserve energy.

4.   Emperors and Adelie penguins are the only two penguin species inhabiting the Antarctic continent proper, although other species live among the northern islands of Antarctica.

5.   These penguins come into much more frequent contact with human beings and the hazards they pose than do the four penguin species that breed in Antarctica.

6.   Two other South American penguin species, the Magellanic and Humboldt, also suffer as waters warm.

7.   Other penguin species, with populations numbering in the millions, live in Antarctica and the southern tip of South America.