San Diego Natural History Museum--Your Nature ConnectionHistory of the Museum

Trip to Trinidad Whaling Station, July-August 1926

Finback Feeding Habits
July 19

Traps did not do so well this morning & held but a couple of shrews.

A 52 ft Finback whale was brought in last night & at 8:30 this morning the large tail muscles & viscera were still steaming with animal heat.

Measurements are assumed to be estimates. Like most of the Finbacks caught near Trinidad that year, this was a young whale – adult Finbacks range from 60-70 ft in length. More Finback whales were caught in the 20th century than any other whale species, and although they are believed now to be “generally abundant in the North Atlantic and North Pacific”, they are protected as an endangered species worldwide

This animal had been feeding on shrimp-like crustaceans about half an inch in length & its stomach contained about 2 barrels of them.

euphausia photo
Euphausia pacifica
At the time of this expedition, whale experts thought that Finbacks had a regular migration route. Researchers currently cannot identify any such migration paths, and have found Finbacks at a broad latitudinal range throughout the year. Experts do not know if Finbacks fast during winter months, like migratory whales. Huey & Howell identified the Finback stomach contents as Euphausia pacifica hansen. All of the Finbacks they observed during this expedition had either these shrimp or small “mackerel-like” fish in their stomachs

We counted the baleen plates & found 328 rows on one side of the mouth. These strainer plates only occur on the upper side of its mouth and in this whale extended about 7 ½ feet along the outer edge on lips. These plates were very short near the front end of the mouth & at the back were about 15 inches in length – being larger towards the outside & shorter towards the place where the tongue should be. The tongue in this species is very rudimentary and indicates that the food is obtained by opening the mouth wide, taking in a large school of small fish or shrimp at the same time, extending the gular pouch. Closing the mouth the gular region is contracted & the food strained from the water by the baleen plates. This operation does not necessarily have to be close to the surface.

Finback Baleen
Huey baleen photo

Baleen is composed of keratin, which is also found in hair, feathers, horns, and fingernails. Finbacks have between 260 and 480 baleen plates on each side of their jaw. Oddly, the left side of a Finback's jaw is black, while the right side is white. This photo shows the right side (the jaw is upside-down) - note the white coloration of the forward-positioned plates.