The primary difference between the 2 suborders, Mysticeti and Odontoceti, has to do with the whale’s feeding hardware. Whales in the Mysticeti suborder have baleen plates that serve as a filter-feeding system, while marine mammals in the
Odontoceti suborder which includes dolphins and porpoises as well as whales have teeth.
Different species of whales vary drastically in terms of both size and weight. Baleen whales in the Mysticeti suborder are generally larger than those of the Odontoceti suborder. The Mysticeti group includes the Blue Whale, the largest animal ever to live on the planet. The species can reach a length over 100 feet long and weigh as much as 150 tons. The Sperm Whale is the largest toothed-whale, reaching up to 70 feet in length and 59 tons in weight. The smallest baleen whale is the Pygmy Right Whale, which averages a length of only 20 feet and a weight of 4 tons. Whales resemble fish because of their fins and hydrodynamic bodies, but have far more in common anatomically with other mammals.
Baleen
Also known as whalebone, baleen is a filter-feeder system inside the mouths of whales in the Mysticeti suborder. Plates of keratin grow from the gums of the upper jaw. When the whales feed, they take in large amounts of food-rich water and then use baleen to filter out the water while retaining krill. Baleen is made of keratin, a substance also found in human fingernails and hair.
Blubber
Blubber is a thick layer of fat under a whale’s skin that helps the warm-blooded animal maintain its body heat under water.
Rostrum
The rostrum is an animal’s beak or a beak-like part of its face. In a whale’s anatomy, it refers to the upper jaw.
Dorsal Fin
A fin located on the back of a wide-variety of aquatic animals including all marine mammals. Its primary purpose is to help the animal maintain balance while it swims.
Pectoral Fins
The pectoral fins are the whale’s forelimbs. The fins have skeletal elements similar to those of terrestrial mammals although externally, they resemble fish fins.
Flukes
Flukes are the tail fins of whales. Flukes are flat and are responsible for propelling the whale through the water.
Blowhole
Blowholes are nasal openings located at the top of a whale’s head. Similar to nostrils in other mammals, blowholes are used by whales to expel carbon dioxide, mucus and nitrogen and to inhale oxygen which is then sent through the trachea to the lungs. After inhalation, blowholes are sealed with a water-resistant muscular flap. Baleen whales have two blowholes while toothed-whales have only one.
Mysticeti whales rely on their baleen to feed on relatively small aquatic organisms. Their diet primarily consists on fish, krill and plankton. Toothed whales are better equipped to grab larger, individual prey animals like fish, squid and other invertebrates. Some species in the Odontoceti suborder have been known to even eat seabirds and smaller marine mammals.
Whales are found in all of the world’s oceans. Species often breed and raise calves in warmer tropic or sub-tropic waters and then migrate to cooler waters at or near the poles to feed. Certain species like the Bowhead Whale that are found exclusively in the Arctic, have a far more limited geographical range. The exact lifespan of whales is not known, but it has been estimated at anywhere from 30 to 200 years of age. Bowheads are thought to have an incredibly long lifespan, reaching ages of 200 years or more.
Social behavior varies depending on species but most whales spend time in groups, primarily during periods of migration. When in groups, whales communicate with each other in a variety of ways including posture, touching, spouting and above-water movements like breaching and lob-tailing, slapping its tail fluke on the water’s surface. While Humpback Whale males are known for their “songs”, most whales use a variety of vocalizations for communicative purposes.
Reproductive habits also vary from species to species but on average, mature whales breed every two or three years with an incubation period of about 9 to 15 months. After giving birth to calves, lactating mothers nurse the babies from nipples concealed in abdominal mammary slits. Calves can swim as soon as they’re born and typically stay with their mother for a year or so.
Small or young whales are susceptible to larger ocean predators including Killer Whales, but whales are most threatened by human activities. Whaling for meat, baleen, oil and blubber decimated whale populations, particularly after the industry took-off in the 19th century. It wasn’t until 1982, that hunting was officially prohibited by the International Whaling Commission. However whaling still occurs, hurting current whale numbers. Although some whale populations are recovering, damage to their habitat, caused by pollution and changes in ocean temperatures that negatively impact food sources remain major threats to the animals.
Additional Facts
* The word cetacean comes from the Greek word for whale, ketos.
* The scientific suborder’s name Mysticeti, most likely derived from the Greek word mystakos, meaning mustache, possibly referring to the baleen plates attached to the whale’s upper jaw.
* Carl Linnaeus humorously gave the Blue Whale the scientific name Balaenoptera musculus. The first word refers to the whale’s dorsal fin (“whale wing”) and the second musculus means “little mouse”.
* The Fin or Finback Whale is the fastest of the baleen whales, reaching speeds up to 34 mph.
* Most species of toothed whales use echolocation to navigate the ocean. No baleen whales are known to have this ability.
* During the embryonic stage, baleen whales develop tooth buds. However, these tooth buds disappear before birth.
* The Narwhal has just 2 teeth: one in its mouth and the other jutting out from the front of the male’s head. The female does not display a tooth like the male. This unusual protrusion is why the Narwhal is nicknamed the “Unicorn of the Sea”.
* Whales do not breathe reflexively. They must make a conscious effort to come to the surface to breathe in air.
* Like all mammals, whales have body hair and nurse their young with milk.
* Also like all other mammals, whales are warm-blooded. They maintain a temperature around 98-99 °F, close to that of humans.
* Whales do not have tear ducts but they do have glands near the eyelid that release an oily substance to lubricate & clean the eye.