Marine Mammals

Cetaceans: Dolphins & Whales Whales and dolphins belong to the order called Cetacea. There are about 80 different species of cetaceans.

The largest are whales. The smallest are dolphins and porpoises.

What is the difference between dolphins and porpoises? In general, dolphins have an elongated snout and can swim faster.

Dolphins and porpoises are known for their intelligence and social behavior

Whales Whales are classified into two main groups 1) Mysticetes or Baleen whales 2) Odontocetes or Toothed whales

Baleen Whales Baleen whales are filter feeders that eat plankton and small fish.

They include: a) Blue whales b) Finback whales c) Humpback whales d) Right whales e) Gray whales

The blue whale is one of the biggest animals that has ever lived on earth. It can reach up to 30 meters in length.

Baleen whales feed by swimming through the water with an open mouth, taking in large quantities of water. The baleen acts like a strainer, allowing water to pass out, while the zooplankton is caught and swallowed.

Some whale species have pleated throats like an accordion that expand in order to take in more water. These pleats are called rorquals.

Baleen plates can be different depending on what that whale species eats. Food of the baleen whale species include: a) zooplankton (copepods) at the surface b) krill and small fish c) crustaceans in the seafloor sediment

Toothed whales Toothed whales include species such as: a) sperm whales b) killer whales c) pilot whales d) beluga whales e) dolphins and porpoises

These whales have peg-like teeth on their jaws, which are used to catch the food before it is swallowed whole. Food of the toothed whale species includes: a) fish b) squid c) penguins d) seals

The largest toothed whale is the sperm whale at 15 meters. The smallest toothed whale is the narwhal at 5 meters (not including dolphins and porpoises).

The elongated tusk of the narwhal is actually a large tooth, used to attract females and to fend off rival males.

Reproduction in Whales Cetaceans are fully aquatic animals. This means they do NOT return to land to breed.

Both fertilization and development is internal. Whales breed about once every 3 years and usually give birth to one calf at a time.

As with all mammals, whales take very good care of their offspring and have strong maternal bonds.

Whales are born tail first. Newborns are pushed by mom to the surface for their first breath.

The whale nurses her calf for 6 to 10 months. The milk is rich in protein and fat (can be up to 50% fat).