Page by Wesley R. Elsberry. Created: 960620 Updated: 980731

As with any other field of study, marine mammals have a variety of interesting terms that might be unfamiliar to the person new to the field. This page aims to make some of those more familiar, anyway.

Ambergris

An aromatic substance occasionally found in the gastrointestinal tract of some great whales, formerly valued greatly in the manufacture of perfumes.

Baleen

Sheets of stranded keratin arranged in overlapping sequence in the mouths of Mysticetes for straining water. The "whalebone" of 18th and 19th century whalebone dresses; a single sheet of baleen from a full-grown right whale could easily exceed 2 meters in length.

Biosonar

The use of sound by animals to gain information about the distance, shape, movement, or other properties of objects in their environment. While research on captive animals has found that biosonar in some species is a highly capable discrimination tool, very little research has been done on how biosonar is actually used in the wild. The simple presence of pulsed vocalizations by cetaceans does not necessarily mean that biosonar is in use, contrary to popular opinion.

Blowhole

The external nares in cetaceans. Cetaceans are air-breathing mammals, and when they surface, they tend to explosively exhale, which is a "blow".

Calf

The newborn or infant offspring of cetaceans or sirenians.

Decibel

A term that causes massive confusion in physics students and others trying to get a grip on acoustics. A "decibel" is not a unit; it is a ratio. As a ratio, each use of "decibel" must be referenced to something. For most people, "decibel" refers to the amplitude of a sound in air, which is a ratio of the measured sound pressure level referenced to 0.000204 microbars. For those dealing with underwater sound, "decibel" refers to the ratio of a measured sound pressure level referenced to 1.0 micropascal. These are not directly comparable measures.

Dorsal fin

An upward projecting fin on the dorsal side of many cetacean species. Dorsal fin shape and trailing edge notch patterns may be used for identification of individual animals.

Echolocation

The use of biosonar for the purpose of determining distance and relative direction of objects in the environment. Just as pulsed vocalization does not necessarily mean that biosonar is being used, so the use of biosonar does not necessarily mean that echolocation is being done. Echolocation is a description of the function of particular biosonar use. Very little work has even approached documenting echolocation being done by wild dolphins. There has been a great deal more speculation than data collection in this regard.

Flukes

The broad, flat, horizontal structures at the posterior end of cetaceans. These are cartilaginous, not bony. The flukes are moved up and down to produce forward motion. Research is going on to make catalogues of photos of great whales for individual identification, since the patterns of notches and coloration on the flukes are highly individualized.

Lek

A lek is a gathering place of a species, specifically for males to display and attract females for breeding. Leks do not contain significant food resources.

Mysticete

Term for the taxon Mysticeti or any whale in that taxon; a mysticete is a whale that has baleen instead of teeth. Mysticetes are filter feeders, straining water through their baleen to capture prey items. Mysticetes include the largest of the whales, the fin and blue whales. The blue whale is the largest animal ever to have lived on earth.

Odontocete

A toothed whale, as opposed to a Mysticete, or baleen whale. Dolphins, porpoises, beaked whales, and sperm whales are all odontocetes.

Pectoral fins

The "flippers" of cetaceans. The pectoral fins are highly modified arms.

Peduncle

The part of the body of cetaceans posterior to the anus and to which the flukes attach.

Pod

Collective term for a group of whales. Many species of cetaceans have apparent long-term associations as a group. Research is ongoing as to the extent of pod cohesion over time.

Pup

The newborn or infant offspring of pinnipeds.

Rorqual

Common group name for the Balaenopterid whales (blue, fin, sei, Bryde's, minke). Rorquals are fast-moving lunge-feeders with relatively short baleen.

Rostrum

The structure formed by the forward-projecting parts of the jaws in some marine mammals. The "nose" of the bottlenose dolphin is actually a rostrum. It really isn't a "nose" at all, since the nasal passages don't come anywhere near it.