Videos of dolphins communicating both in captivity and the wild:
https://www.youtube.com/watch?v=YSjqEopnC9w
https://www.youtube.com/watch?v=4Un61qv_QIc
Some Species
Bottlenose Dolphin
Spinner Dolphin
Amazon River Dolphin
Orcas
Nota:
Though commonly referred to as "Killer Whales", Orcas are actually part of the order Cetacea, which excludes whales and porpoises.
http://animals.nationalgeographic.com/animals/mammals/killer-whale/
Whales
Behaviors
Feeding using "Bubble Net Fishing"
Nota:
Here is an amazing video displaying this hunting technique used by pods of whales:
https://www.youtube.com/watch?v=z00G0RxeSP0
Live both in pods and solitary
Nota:
More so than dolphins, many whale species prefer traveling alone or with flexible and dynamic groups. The strongest bonds occur only between a mother and her calf.
http://www.enchantedlearning.com/subjects/whales/glossary/Pod.shtml
Communicate with song-like noises
Nota:
Here is a prime example of two whales communicating to each other:
https://www.youtube.com/watch?v=WabT1L-nN-E
Some Species
Blue Whale
Nota:
At around 100ft and 200 tons, Blue Whales are the largest animals to have ever existed, even larger than any species of dinosaurs.
Sperm Whale
Baleen Whale
Seals and Sea Lions
Behaviors
Amphibious Lifestyle
Feed on fish, crabs, birds, krill, and other available food
Live in large groups called "colonies"
Nota:
Colonies can grow to thousands of seals during mating and birthing season
https://www.youtube.com/watch?v=14GxXU4WO1w
Some Species
Harp Seal
Elephant Seal
Nota:
Southern Elephant Seals are the largest of all the Pinnipeds, growing upwards of 20ft and weighing up to 8800lbs
http://mentalfloss.com/article/73596/14-huge-facts-about-elephant-seals
Leopard Seal
Fish
Anatomy
Gills for breathing oxygen through
the water
Nota:
On average fish have 3-7 pairs of gills
Scales often cover the body
Nota:
Though this is not always true, such in the case of catfish, lampreys, hagfish, and more
Tail, Dorsal, and Pectoral fins
Behavior
Live in large groups called schools
Nota:
Some species prefer solitary life, such as Sailfish or Barracuda
https://www.youtube.com/watch?v=tygpCEOYDUw
Technically a GoPro ad, the video offers a great view of the inside a school of wild Silver Fish!
Feed on other fish, plants, and
smaller plankton and krill
Communicate mainly with
body language, though
some use sound
Species
Angelfish
Marlin
Gold Fish
Crustaceans
Anatomy
Composed of 3 Segments:
Head, Thorax, and Abdomen
Exoskeleton protects the
soft inner-body
Nota:
Every so often, the crustacean needs to molt, or shed it's large exoskeleton
https://www.youtube.com/watch?v=4QIgW639Oog
Antennae, legs, and other
extensions specific to
species
Behavior
Communicate through
body language and
scent
Nota:
Lobsters, for example, secrete special urine from their faces to communicate with each other
http://www.huffingtonpost.com/2015/06/15/facts-about-lobsters_n_7568976.html
Often live in groups, but
some are solitary
Eat a variety of food, from small krill
and fish in the water to large fish
and other crustacean
Species
Snow Crab
Crawfish
Lobster
Sharks and Rays
Nota:
Sharks and Rays are special because they are both cartilagenous fish. This means that instead of bones, they are made of cartilage!
http://www.wiseoceans.com/seasense/sharks-rays/
Sharks
Some Species
Great White
Thresher Shark
Nota:
Threshers hunt by using their long tails to stun fish, and then eat them while they recover from the blow.
Angel Shark
Nota:
Angel sharks are a great example at the similarities that sharks and rays share beyond their cartilage!
Behaviors
Solitary versus social behaviors vary
between species
Though mislabeled as "man-eaters", sharks appetites vary as widely as humans depending on the species.
Tiger sharks are known as the "Trash cans of the sea", while Whale Sharks tend to only eat krill and other small fish, similar to whales