Week 2
10 July 2006

Seals of the Southern Ocean

There are two groups of seals common to the Antarctic and subantarctic, photid seals (without ears) and otiid seals (with ears.)  Information about seals used to come from observations on land and sea, but now electronic tagging techniques are also used. Seals depend exclusively on the ocean for food.

Why were the following seals named for other animals?

The Southern Elephant Seal

This is a seal of huge proportions. Males grow to a length of 4.5-6.5 meters and can weigh up to 3700 kg. Females are considerably smaller. They range in length from 2.5-4.0 meters and weigh “only” 359-800 kilograms.

Question: How much would a large male African elephant weigh in kilograms?

Elephant seals are clumsy on land, due to their massive size and small flippers. They use a caterpillar-like motion to move their bodies forward. Adult males have a proboscis.  Adults eat mainly fish and cephalopods.

Elephant Seals Photograph by: Rebecca Shoop National Science Foundation Link

*How Words Work: Cephalo comes from the Greek word for head. Pod comes from the Greek word for foot.

Question: What kinds of sea creatures are categorized as cephalopods?

The Elephant Seal Book of World Records:

1. An elephant seal has been recorded at a depth of 1444 meters. How far is that in miles? (Use a fraction or decimal for your answer.)

2. An elephant seal was able to hold her breath for 2 hours. Males cannot stay under as long. What are some of the longest times people have been able to hold their breath?

Normally, dives last from 20-30 minutes and reach 400-600 meters in depth.

	Conservation facts: Although the elephant seal was hunted almost to extinction in the19th and early 20th centuries, it is now protected at all breeding sites. The last commercial exploitation continued on South Georgia Island until 1964.
	Question: Look on a map, find Antarctica, and then look for South Georgia Island. What is the latitude? What is at that latitude in the Northern Hemisphere? Are there seals there?

The Leopard Seal

While elephant seals are huge like land elephants, leopard seals are long and slim with spots that can be grey or black. Their heads are more reptilian than like those of a leopard. They have a long snout, powerful jaws, and small dark eyes. In contrast to the elephant seal, the female leopard seals are larger than the males. They can reach 3.8 meters in length and weigh about 500 kg.  Males range from 2.8 -3.3 meters and weigh about 300 kg.

Leopard Seal - Photo by Steve Ebbert Link	Young Leopard Seal - Photo by: Robin Muench Link	Leopard Seal - Photo by Steve Ebbert Link

The adults eat krill (what’s that?), fish, seabirds (especially penguins), young seals and, like the elephant seal, cephalopods.

The leopard seal can behave aggressively near boats.

Leopard seal - Photo by: Robin Muench Link

Conservation facts: The leopard seal is protected and has never really been hunted for commercial purposes.

Human/Elephant Seal Interactions

In case you get a chance to visit Antarctica (you never know!), remember to follow the guidelines for observing each species. Elephant seals usually remain motionless if an observer approaches, but you should keep a distance of at least 10 meters. (How are you going to know how far 10 meters is? Is it the length of your classroom?) Keep at least 50 meters from the leopard seal.  Can you think of something related to swimming that is 50 meters? Stay out of range!