Eschrichtiidae Family of Gray Whales

One Gray Whale of the Eschrichtiidae Family can be found in this website:

Gray Whale, Eschrchtius robustuspolychaete. A representative of the Escherichtiidae Family of Gray Whales.

Phylogeny:  The Eschrichtiidae Family of Gray Whales are marine mammals in the phylum Chordata.  They are in the class Mammalia and the order Artiodactyla, the same order as hoofed ungulates, from which they evolved. They are in the infraorder Cetacea, which are the Baleen and Toothed Whales. They are in the superfamily Mysticeti of baleen whales. The Eschrichtiidae Family is one of four families in this superfamily. There is only one genus and one species in the Eschrichtiidae Family – the Gray Whale Eschrichtius robustus. Historically there were two genera in this Family during the Pliocene Era, 2,580,000 to 5,330,000 years ago, and just one in the Miocene Era, 5,330,000 to 23,000,000 years ago. The Escjerocjtoodae Family and the Eschrchtius Genus are named in honor of the Danish zoologist Daniel Frederik Eschricht.

Morphology: Gray Whales are large bodied, with a dorsal hump and 6 to 12 smaller bumps running along the ridge from the dorsal hump to the flukes. The flukes and flippers are of moderate size. Viewed from above, the head is narrow and tapering. The mouth is slightly arched. They have mottled gray coloration. Whitish barnacles, scars, and whale lice are usually scattered about the body and head. They raise their flukes when diving. Gray Whales measure 4.9 m (16 feet) at birth and weigh 680 kg (1,500 lbs). Adults reach 15 m (49 feet) in length and 35,000 kg (80,000 lbs) in weight.

Habitat and Distribution:  Gray whales are generally found in open ocean waters, over the continental shelf. Most of the time, they are in shallow coastal waters. There are at least two distinct populations of Gray Whales- the Eastern North Pacific and the Western North Pacific. The Eastern North Pacific population breeds and calves in warmer lagoons and bays along the Baja Peninsula and southern Sonora, Mexico. They spend summers feeding in the cooler waters of the Bering Sea, Chukchi Sea, Southern Alaska, British Columbia, and Northern California. The Western North Pacific population breeds and calves in the South China Sea and feeds in the Sea of Okhotsk. Historically, in Mexican waters Gray Whales were found throughout the Sea of Cortez. Whaling activities appeared to extirpate them from the northern portions of the Gulf. Within the past few decades there have been occasional sightings at least as far north as Bahía de Los Ángeles, Baja California. They are found along the entire west coast of the Baja Peninsula, either migrating or in their calving grounds. Laguna Ojo de Liebre (Scammon’s Lagoon), Laguna San Ignacio, and Magdalena Bay are primary calving locations along the Peninsula. Tojahui and Yavaros, Huatabampo, Sonora and Bahía Santa María, Sinaloa, are the primary calving locations along the mainland coast. The North Atlantic population of Gray Whales was thought to have been extirpated since the 1700’s. Within the past two decades, sightings of Gray Whales in the Atlantic Ocean and Mediterranean Sea have given hope that Gray Whales are either recovering in that area, or vagrant whales are moving in from the Pacific. Eastern North Pacific Gray Whales migrate south, in the fall, for 2 to 3 months, covering 8,000 to 11,000 km (5, 000 to 6,800 miles). The return the following spring. They seldom venture more than 10 km (6 miles) from the coastline during migration.

Reproduction: Gray Whales reproduce through sexual reproduction, with internal fertilization. The gestation period is between twelve and thirteen months. Females calve at two to three year intervals. Calves mature within seven to nine months, in time to be independent for the next southward migration.

Ecosystem Interactions: Gray Whales can feed either benthically or planktonically.  When feeding on plankton they roll onto their side, skim the water with their mouth open, and filter out the food by expelling the water through their baleen plates. With this method of feeding, they eat crab larvae, small fish, herring eggs, various other forms of larvae, and polychaete worms. When benthic feeding, they roll onto their side and scoop up sea floor sediments, expel the sediments through their baleen plates and filter out food such as amphipods, isopods, polychaete worms, mollusks, and other invertebrates. Gray Whales have also been observed lunge feeding on anchovies, though this seems to occur rarely.  Killer Whales are the primary predator of Gray Whales. Great White Sharks will also attack Gray Whales calves or injured whales. Gray Whales host Whale Lice (cyamids) and three species-specific types of barnacles.