What makes sharks, dolphins, and whales different from fish?

Question

Why are sharks, dolphins, and whales have their own names? Are they considered different from fish or are they a type of fish? If they're different, what's unique about sharks, dolphins, and whales?

Answer 1

A shark IS a fish - it has a cartilage skeleton, rather than a bony skeleton as most other fish do, so it's in a different classification

A dolphin can be a freshwater fish: http://www.cichlidlovers.com/c_moorii.htm , a saltwater fish: http://www.caudata.org/cc/images/articles/critters/planaria1JOHNSON.jpg or a mammal: http://www.ilvydolphinswimteam.org/images/Dolphin201.jpg , so you have to be specific when you tell someone about these which one you're talking about!

A whale is usually a mammal (like the killer whale, sperm whale, blue whale, humpback whale, and more), but there's a freshwater fish called a "baby whale" that's not related: http://badmanstropicalfish.com/stats/misc_stats/stats_misc1e.html

The major differences between fish and whales is that fish are ectothermic, maning they don't regulate their body temperatures. Mammals, like whales and bottlenose dolphins which are endothermic, do regulate body temperature.

But when people discover new species, they might think that the new fish looks like something else, so it becomes a part of that new fish's name - that's how the baby whale gets its name. Also, you can but several tropical fish called sharks, but even though they're called "sharks", they are catfish and minnows that have a bony skeleton. It gets confusing, doesn't it?

Answer 2

First of all, Sharks really are fish. But, most fish have a bony skeleton. Sharks have cartaliganeous skeletons. Dolphins and Whales are very different from Fish. Dolphins and Whales are mammals and breathe air (it dosen't look like it because thier in the water!)

Answer 3

For one thing, Dolphins and Whales are warm blooded Mammals--not cold blooded fish, but all three of these species have a womb for developing the young INSIDE the body as opposed to OUTSIDE the body. They do not lay eggs. Some other fish like aquarium Guppies and Mollies and Sunset fish-- also carry their young INSIDE--and then they drop them after they have developed. But. These latter fish do not protect their young as do the Shark, the Dolphin and the Whale--they will eat them if they get the chance!

Answer 4

The dolphins and whales are mammals. Sharks are primitive fish, their skeleton isn't made of bone, but of cartilage.

Answer 5

dolphins and whales are mammals which are warm blooded. Sharks are fish which are cold blooded.

Answer 6

Yeah that's right.

Sharks are fish. Cold blooded with gills.

Dolphins, porpoises and whales are mammals. Warm blooded, give birth and breathe with lungs.

They have their own names because they are subclasses.

For instance-
Reptiles will include snakes, turtles, crocodiles, alligators and lizards as subclasses

Mammals will include canine, feline, primates, marsupials, whales, dolphins as subclasses

Fish will include rays & sharks, eels, catfish, lungfishes as subclasses

Answer 7

Dolphins and whales are mamals and sharks have no bones.