Grey Whale Vs. Blue Whale: A Comparison Guide

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The grey whale and the blue whale are some of the ocean’s most enamored species. Each of these incredible whale species has its very own characteristics and qualities that make it extremely unique. Without further ado, we’ll go through and break down the most significant differences between blue and grey whales.


Probably one of the most significant differences between the grey whale and the blue whale is the size, length, and mass. The blue whale is the largest mammal to ever exist on the planet. An adult blue whale weighs 300,000 lbs. and spans a whopping length of 79-82 ft (females being slightly larger than males). To put this in perspective, it’s equivalent to the length of about 3 full-size buses!

While the blue whale is the largest animal on the planet, the grey whale is still massive in size as well. The grey whale is the seventh largest whale species, weighing 60,000 lbs. and spanning 39 feet in length.


Another difference between the grey whale and blue whale is obviously it’s color. The gray whale has a deep slate gray color. It is distinguished by its gray-white patches all over its body, left by feeding parasites that drop off seasonally.

Blue whales are a dark blue gray color when viewed out of water. But when the light hits them underwater, they can appear to have a deep blue color. They also have some lighter patches over there body, but they also have slightly yellow-white underbellies due to millions of microorganisms living on them. While the gray whale has no dorsal fin, the blue whale has a small dorsal fin on the top of its back that curves back slightly.


Blue whales are known to have a global distribution in all regions of the world except the Arctic. They prefer deeper ocean waters to coastal waters.

Unlike blue whales, gray whales are shallow-water feeders, so they prefer staying closer to coasts. There are a few well known gray whale populations, which can be found mostly in the eastern North Pacific, but some in the Western Regions as well.


Blue whales are a very endangered species and the largest known concentration of them is believed to be 2800 in the northeast Pacific. To this day, they remain one of the rarest whales you can encounter.

Grey whales, on the other hand, are much more populous with over 26,000 in existence today. Of these 26,000 grey whales, 99% of them are eastern North Pacific grey whales whereas the remaining 1% are western grey whales.

Migration Patterns

Grey whales have one of the most exciting yearly migrations, especially on the West Coast. The eastern North Pacific grey whale population feeds around Alaska and Russia during the summer and migrates down to Southern California and Baja Mexico during the winter. The Western population of grey whales migrate to their feeding grounds in Russia during the summer and return to the South China Sea later in fall to breed.

The migration of blue whales, however, is slightly more unpredictable, making them a rarer species to encounter. Blue whale populations tend to migrate closer to the cooler waters in the poles during the summer where they feed and migrate back towards the warmer waters in the winter to breed.


Blue whales are currently considered federally endangered. In the 1800s and early 1900s, blue whales were on the brink of extinction due to commercial whale hunting practices employed mainly in part by the Soviets. were very abundant with about 250,000 in existence, but soon after they became targets for recreational whale hunting by the Soviets in the 1960s. In 1966, blue whales became protected by the International Convention for the Regulation of Whaling, which banned whale hunting altogether. In 1970, the blue whale was listed as endangered under the Endangered Species Conservation Act (ESA). Since then, their population has rebounded slightly but their population is only a fraction of what it used to be. The primary threats they face today, however, are ship and boat strikes and entanglements in fishing equipment.

Currently, the grey whale population is stable and does not face endangerment threats.

Feeding Habits

Blue whales eat krill (a lot of it) and copepods. It is estimated that blue whales need about 2,200 lbs. of food to fill their stomachs and require about 8,000 lbs. of food every single day (that’s 40 million krill!).

Gray whales’ favorite food are amphipods and mysids, which are tiny shrimp-like animals. Gray whales are considered “opportunistic eaters”, so you can find them consuming a lot more than that as well.

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