andrewt@cs.su.oz (Andrew Taylor) (11/01/90)
[This is an article I posted to rec.scuba during a discussion about diving animals, I realised later than rec.birds people may be interested so ...] Some Australian researchers put depth-recorders on 10 Emperor Penguins, presumably the highest-performance diving birds. During the 3 weeks they were logged 6 went below 300m and one reached 458m! The deepest dive known for a bird. The dive lasted 10 minutes with 3 minutes below 400m! It ascent and descent rate was about 2.2m/sec (this is about normal cruising speed for an emperor). Its 2 previous dives were also below 400m. The bird, a male, probably wasn't at its fittest as it just finished incubation. This involves standing on the ice non-stop for 2 months in the darkness and 60C windchill of with a large egg held between its legs. After all this it has 70km walk to the sea for its first meal in 4 months. It still has 5 months of chick feeding ahead. Its not easy being a penguin. I doubt if its known how Emperors avoid decompression problems. One of my books says they take a full breath before descending using the oxygen in their lungs, blood and muscles before resorting to anaerobic respiration. I wouldn't be suprised if they could reach 1000m, an 18 minute but shallower dive has been recorded. They often have only a short surface interval between dives. Andrew, who'd rather see a penguin than a Whale shark on his next dive