Gray whale

Eschrichtius robustus

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The family Eschrichtiidae only contains one genus and species, the Gray whale (Eschrichtius robustus). Only found in the Northern Hemisphere, the Gray whale can easily be observed along the West Coast of North America, where it performs unbelievably long migrations from its summerly feeding grounds in the Bering Sea to the world-famous winterly breeding lagoons of Baja California (Mexico) and back, for an overall 20000km (12400 miles) round-trip.
A small number of individuals, though, prefer to spend the summer in British Columbia, rather than travelling all the way up to the Arctic. Whale Watchers need to know that the Mexican breeding lagoons (San Ignacio, Guerrero Negro, etc.) are all on the Pacific coast of Baja California; do not look for Gray whales in the Sea of Cortez, you will not find any! A second, much smaller population of Gray whales can be seen in the Okhotsk Sea (Siberia, Russia), during summer months and migrates to South Korea for winter. Strikingly, the Gray whale does not feed at all in winter, and it is known to lose as much as 30% of its weight between summers. Some characteristic features of this species are:
  • Mottled gray colour, with relatively tiny white patches
  • Arched head and mouth.
  • No dorsal fin
  • Two pleats (throat grooves)
  • Flukes are raised above the water surface when deep diving
  • Moderate to huge amount of parasites, such as barnacles and whale lice
Female Gray whales are generally larger than males. Mating occurs between December and January, and gestation lasts for about 13 months.
The newborn rapidly gains weight by drinking its mother's fat-rich milk, and when 2 or 3 months old it is already strong enough to face its first migration.
During the long journey, though, mother and calf must face dangerous situations, especially when crossing the Monterey Bay, where Transient Orcas (Orcinus orca) are known to attack such pairs of Gray whales and to prey on calves. The Gray whale is a bottom-feeder, its diet being mainly based on benthic crustaceans called Amphipods. This also explains why it is mainly found in relatively shallow waters.
When feeding, the Gray whale rolls onto its right side ("left-handed" individuals are known but rare), and sweeps the bottom engulfing large amounts of sediment and food, which is then filtered by means of its short baleens as water and silty water is pushed out. The Gray whale is naturally inquisitive, it often spyhops, lobtails and breaches. In our experience, it is definitely the most friendly, curious and playful of all toothless whales. When breeding lagoons were discovered by former whalers, Gray whales were slaughtered to the brink of extinction. Newborn were often harpooned so that mother whales would not leave and could be easily killed as well.
The Gray whale was nicknamed Devil Fish by whalers, because of the aggressive behaviour shown by females in the desperate attempt to save their young.
Luckily, despite human stupidity, these gentle creatures have survived in sufficient numbers for the Pacific population to recover, at least in North America.