Learn about the amazing gray whale, a conservation success story, with guest presenter Mike Owyang.
Mike Owyang is an ambassador animal keeper and education specialist at the Sacramento Zoo in CA, USA. His job includes the care and training of animals that are part of the zoo’s education programs and featured in wildlife presentations, outreach programs, animal encounters with zoo guests, and media appearances. Mike is a keen nature photographer who has photographed red pandas in Nepal and marine mammals off the coast of North America.
Gray whales (scientific name: Eschrichtius robustus) are simply awesome creatures. They were near the point of extinction when humans were hunting them but they have come back to a very healthy population of almost 20,000. This was because people cared about the whales and wanted them protected. Gray whales were one of our country’s early conservation success stories.
Some gray whale facts:
Gray whales spend their summer feeding in the cold Arctic oceans in the far north.
They are known as baleen whales and mostly feed on small invertebrate creatures that are like shrimp (invertebrates are animals without a backbone). Instead of teeth, they have baleen, which looks like a comb and is used to trap the food they eat.
The gray whale will swim sideways along the sea floor, scooping mud and these small animals into their mouth. They push out the mud and water, which traps the invertebrates in their baleen and then they swallow them.
When they are feeding, most gray whales swim on their right side, the same way most people are right-handed, but some whales swim along the sea floor on their left side sort of like a left-handed person!
Gray whales will also feed as near the water surface, catching and gulping down other small animals like krill, shrimp, and fish.
An adult gray whale can grow to over 50 feet (15 meters) long and weigh almost 80,000 pounds (36,000 kg) so it has to eat a lot of food to fill its stomach.
After spending the summer feeding and gaining weight, the gray whales can then begin their migration to the warm waters off Baja California in Mexico to spend the winter. The whales mostly head to three lagoons (or bays) to give birth to their young (a baby whale is called a calf) and to mate. This migration can be over 10,000 – 12,000 miles (16,000 – 19,000 km) round trip!
The whales swim almost constantly without stopping for a break or to sleep. This is because whales, dolphins, and porpoises (known collectively as cetaceans) breath air like we do, but unlike humans and other mammals they need to be awake to come to the surface of the water to exhale and take a breath through their blowhole.
The blowhole is like our nostrils but it is located near the top of the whale’s head. The whale’s brain is like ours with two halves, but unlike us, they can rest one side of their brain while the other side stays awake. This way they can breathe and continue swimming constantly.
Gray whales were hunted in the past:
Many years ago when the gray whale was hunted by people, it was mostly to be sold for their blubber (or fat). Hunting was done in the lagoons because most of the whales were all there together during the winter months. Gray whales were almost hunted to extinction in those lagoons. There were so few gray whales left that the hunting stopped because the whalers couldn’t make enough money anymore.
Years later when the gray whale population began to slowly come back, unfortunately so did the hunting. This time instead of traveling to the lagoons, whalers began using large ships to hunt the gray whales as they migrated along the North American coast.
Fortunately for the gray whale, they began to be protected in the 1930’s and 1940’s and by the 1980’s commercial hunting in North America was ended. With proteciton, the gray whale population has grown back to around 20,000 whales. That’s probably not as many as there once were, but scientists believe it is a healthy population.
Most of the gray whales that we know today migrate in the eastern Pacific along the North American coast, spend their summer in the Arctic oceans, and winter in Baja California, but there is also another, smaller group that lives in the Pacific Ocean that we know less about.
This smaller group of gray whales spend their summer in the western Pacific near Russia, Korea, and Japan, and then migrate south to an area near China. There are only about 240 of these gray whales and they are considered endangered.
These gray whales aren’t being hunted like the ones living along the North American coast once were, but they are threatened by off-shore oil drilling and commercial fishing in parts of the ocean where they live.
About 10 years ago, biologists discovered something interesting about this group of whales. Using photos to identify them and satellite tagging to track them, they discovered that some were actually migrating across the far North Pacific to join the gray whales that were migrating to Baja California!
No one is exactly sure why they are swimming an extra couple thousand miles to meet up with their Eastern Pacific cousins but it is just another cool thing about gray whales!
Current threats to gray whales:
Like most of the wildlife on our planet, gray whales are being affected by climate change. The part of the ocean where they go to feed has been warming and there is probably less food to eat to be ready for their long migration to Baja California and back. Some gray whales have even made changes to how and where they eat in order to survive, but this can only be done by a small number of the whales.
Right now, there are more gray whales dying during migration than in other years because they don’t have enough fat stored in their body to stay healthy, or to be able to feed their calves the milk the calves need.