They are tiny little shrimps, less than an inch long, like the kind you see in the frozen food section of the supermarket.
Penguins can have all sorts of different shapes, with the biggest, the emperor penguin, being around 3-4 feet tall. Most of the penguins that I saw were only a foot or so tall, and you can tell them apart by the color of their heads. Gentoos have white patches behind their ears, while adelies don't. Chinstraps have little black straps around their beaks.
Seals are more difficult to tell apart. The Weddell seals have a boxy shape and a short, cat-like face. Crabeater seals are leaner and have a longer, dog-like face. The leopard seal is much bigger, often over 1,000 pounds, and has a big, snake-like face with a mouth that can open super wide. Elephant seals are even larger than that and have fat, elephant-like noses.
You rarely get to see whales up close, so you have to tell them apart by their tails and their spouts when they breath. I only saw a fin whale, which has a short spout and doesn't bring its tail out of the water when it dives.
The most entertaining animal to watch is the penguin, which has a dramatic little life in the rookery. When it's finding its mate, they do little bows to each other, and when they fight, they slap each other with their flippers. I had a lot of fun just sitting in the snow and watching them go.
The most frightening animal to see is the leopard seal. Ernest Shackleton wrote about being stuck on the ice for 17 months, and leopard seals would occasionally try to hunt him and his men. So when I saw one laying on the ice, and it turned to watch us, I couldn't help but wonder if it could get into our little zodiac.
