Gray Whale Gray Whale
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Field Notes from Tom Lewis

March 17, 2000

Hello Fellow Scientists!
Gray whales use San Ignacio Lagoon as both a mating ground and a nursery. This is where mother gray whales teach their babies how to be a whale. When a baby gray whale is born, it is about 12 to 15 feet long, and weighs 1500-2000 pounds! These very big babies must first be taught how to swim. Sound easy? Not exactly!

Growing Tough Enough to Brave the Seas
When we see a brand new baby gray whale, its flukes and flippers are very floppy, and have not yet become rigid. It is very difficult for these newborns to swim fast enough to keep up with an adult, so the mothers move very slowly, and are very protective of their young. Once the calves' flukes and flippers have gained strength, they begin to explore the lagoon. Mothers carefully swim with their babies around the lagoon, gradually teaching them how to swim. However, they do this in a very specific manner. The majority of the whales, and particularly the mothers with calves, swim in a predictable pattern while inside the lagoon. The tidal current inside San Ignacio can be very strong, as much as 2-3 knots. The mothers and calves swim against the tidal current. If there is an incoming tide, they will swim toward the mouth of the lagoon. If there is an outgoing tide, they swim toward the upper end of the lagoon. This pattern helps to protect the young calves from accidents, and prepares the calves for their life in the open ocean.

Learning to Behave Like a Whale
Baby gray whales also have to learn how to do other things before they leave the safety of the lagoon. Gray whales perform several social behaviors, which allow them to function in the whale world. One of these behaviors is called breaching. Breaching is when a whale leaps nearly completely out of the water, then crashes back into the water with a tremendous splash. Another of these behaviors is called spyhopping. When whales spyhop, they rise out of the water slowly, usually (but not always) clearing their eye above the waters surface. They hold this position for a few seconds, then slowly slip back into the water.

Scientists have been puzzled about the purpose for these behaviors for many years. There are many different ideas about why whales breach and spyhop, but no one knows for certain. Most scientists believe that breaching is a form of communication between whales. They may be telling other whales their location, that there may be danger nearby, or it could be an aggressive display meaning "get away". We frequently see baby gray whales learning these behaviors from their mothers. The mother will breach, then itís the babyís turn to try. At first they are not very good at it, but eventually get enough strength and experience to accomplish the task. The function of spyhopping is also not fully understood. Most scientists believe that spyhopping may have something to do with the courtship and/or mating rituals. Gray whales frequently spyhop while the lagoon. They are less frequently seen spyhopping along the migration route, and rarely seen spyhopping while in their feeding grounds in Alaska.

It is often very funny to watch baby gray whales learning these behaviors. They struggle getting out of the water far enough, then clumsily flop over. It takes the calves a few weeks to gain the strength to begin performing these behaviors on a regular basis. This could be compared to the efforts of human babies learning how to crawl and walk.

Friendly Dolphins in the Mix
This is a very interesting year in San Ignacio. Every year we see bottlenose dolphins inside the lagoon. They come into the lagoon to feed on the numerous fish species that live in the lagoon. They often swim along with the gray whales, and we have even seen them bow riding the wave that is produced by gray whales as they swim. This year, there are an unusually large number of dolphins in the lagoon. We saw them many times each day.

Bring on Those Hors d' Oeuvres!
On our last day in the lagoon we followed a young gray whale, probably 1 year old, for several minutes. This young whale was stirring up mud off the bottom of the lagoon as it swam. Frequently, gray whales will attempt to feed while in the lagoon. You can imagine that they get very hungry after a 6-month, no-food diet! This whale was trying to find food the same way whales feed in the Alaskan feeding grounds. We have also seen gray whales running eelgrass (a long, slender seaweed) through their baleen. Why? They are probably trying to eat the shrimp and other small creatures that live on the eelgrass.

Until Next Time
While I was in San Ignacio, we learned about the decision to halt the plan to build the salt works on our last day in the lagoon. What a great way to say goodbye to this very special place!

I will be returning to San Ignacio on March 22 to lead an ACS tour, and will be filing another report after I return. That's all for now!

Tom Lewis

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