The brave journey of gray whales to the mexican waters
Article by Katia Silva, Marine Biologist and Guide at Cabo Trek
Every winter, hundreds of Pacific gray whales return to their traditional breeding and birthing grounds in sheltered Magdalena Bay on Mexico’s Baja Peninsula. Their migration from Alaska’s Bering Sea to the warm waters of Baja’s Pacific lagoons is the longest mammal migration on Earth. Nearly hunted to extinction in the past, these gentle giants have made a dramatic comeback. Friendly and engaging, they are often intrigued with humans, swimming right up to our open boats.
After 8 years the young gray whales will reach sexually maturity and can begin mating and reproducing.
Calves can swim as soon as they are born and can double their weight in about three months, and double their length in about two years.
A female will give birth only once in two years, usually to a single calf after a 12 month gestation period. Most gray whales calve in the lagoons of Baja California, and as with all cetaceans, the young are born underwater and are able to swim immediately. The calves depend on a diet of rich milk for at least six months. They are weaned the following summer at seven to eight months, though young whales will often stay with their mothers for an additional one or two years.
In terms of lifespan a healthy gray whale is estimated to an average lifespan of 50 – 70 years.
Gray whales prefer to stay close to shore. As a result, they are one of the more recognizable whale species. They are bottom feeders and hunt for their prey by swimming to the bottom of the ocean, turning on its side and scooping up sediments from the sea floor.
The National Oceanic and Atmospheric Administration (NOAA) declared last season the whale die-off an “unusual mortality event,” a designation that triggers greater scrutiny and allocation of more resources to determine the cause.
Many have little body fat, leading experts to suspect the die-off is caused by declining food sources in the dramatically warming waters of the northern Bering Sea and Chukchi Sea off Alaska.
International bans on commercial whaling in the 1930s and ’40s helped the species recover.
With the population again recovered, there are now about 27,000 North Pacific grays, which is close to their historic population.
We are hoping that the whales will come back healthy this year and come to visit us in Mexican waters to give birth to their adorable playful babies.
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