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Getting to Know Dolphins
The Cetaceans
Intelligence
Dolphin Variety
Communication
Dolphin or Porpoise?
Help The Dolphins
The Order of Things
(Scientific Classification)
Class: Mammalia
Order: Cetacea (“large sea dweller”)
The scientific order Cetacea includes all whales
Suborder: Odontoceti (toothed whales)
Contains nine families, including:
Family: Platanistidae (river dolphins) 5 species in 4 genera
Family: Delphinidae (dolphins) 32 species in 17 genera
including:
Common dolphin, killer whale, and pilot whale
Family: Phocoenidae (porpoises) 6 species in 3 genera
Cetaceans
Dolphin or Porpoise?
Dolphin Variety
Communication
Intelligence How to Help
What’s the Porpoise?
Dolphin and porpoise are often used interchangeably, but they are not the
same (see Cetaceans). Do you think you know the difference? Test your
Delphinidae and Phocoenidae knowledge. Going in order from 1 to 4, click
on P for a porpoise characteristic or D for a dolphin characteristic.
1. Porpoises are
1. Small social groups
usually found in
small
groupshave
of 2-4.
2.
Porpoises
flat
Many types teeth.
of
shovel-shaped
dolphinshave
gather
in
Dolphins
pointed
3. much
Thereshaped
are 6 species
larger
social
coneteeth. of
porpoises,
groups.
5 species of
4. and 32
river dolphins,
species of marine
dolphins.
2. Cone shaped teeth
3. Six marine species
4. A short, blunt snout
Cetaceans
Dolphin or Porpoise?
Dolphin Variety
Communication
Intelligence How to Help
All In The Family (Delphinidae)
Dolphins Are Whales, but Some Whales Are Dolphins!
Bottlenose Dolphin
Pilot Whale
Killer Whale
Cetaceans
Dolphin or Porpoise? Dolphin Variety
Communication
Intelligence
How to Help
Sounds and Echolocation
Dolphins produce clicks and sounds
that resemble moans, trills, grunts,
squeaks, and creaking doors. They
also produce whistles. They make
these sounds at any time and at
considerable depths.
Click here to
hear a Dolphin
Dolphins produce sounds for
two overlapping functions:
communicating and navigating.
Click here to see how
echolocation works
Dolphins direct "clicks" into the
water and the clicks rebound off solid
objects (fish, logs, boats) and echo
back to the dolphins. Dolphins listen
for the strength of the rebounding
clicks to identify what the object is
and its distance from them. This is
known as echolocation.
Cetaceans
Dolphin or Porpoise? Dolphin Variety
Communication
Intelligence
How to Help
Intelligence
Dolphins are considered some of the smartest animals in the world, in
part due to their elaborate social structures and relatively large brains
Dolphins go through a long “childhood” and thus have an extended
time to learn complex rules and communication
The bottle-nosed dolphin has the second-largest brain to body size
ratio of any animal, second only to human beings
Some dolphins are very receptive to training and performing
Researchers have taught dolphins a sign language in which signs are
recognized as well as how their order affects meaning (syntax)
Dolphins can mimic both sounds and physical behaviors
Dolphins can determine when an object is not present or visible
suggesting they have an abstract grasp of the meanings of symbols
Cetaceans
Dolphin or Porpoise?
Dolphin Variety
Communication
Intelligence How to Help
Help The Dolphins
Tens of thousands of porpoises and dolphins are dying every year due to problems
caused by people. Many get caught in fishing nets and drown while others are
exposed to pollution and toxins that can make them sick. Some species are also
hunted commercially in other parts of the world.
• What you can do to help:
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Keep informed on current issues
Write to government officials about your concerns
Support laws that protect dolphins and their ocean home
Recycle your trash and use less plastic
Buy products that are dolphin safe
Participate in beach clean ups
• For more information, visit these pages on the web:
 Defenders of Wildlife www.defenders.org/wildlife/dolphin/dolphinsum.html
 Friends of the Ocean www.friendsoftheocean.org/si_dolphin.htm
 Save the Dolphins
www.savedolphins.org
Cetaceans
Dolphin or Porpoise? Dolphin Variety
Communication
Intelligence
How to Help