So imagine that you’ve just arrived for a visit to Planet Earth. One of your Earthling friends offers to take you on a marine discovery adventure. You are super stoked, because there are no seas on your home planet! You board a submarine and head into the Pacific Ocean’s deep waters, off the coast of Mexico. You brace yourself for the experience of a lifetime.
Before long, you hit the jackpot. First, you observe a large, spotted, creature slowly glide by the observation window. Your guide explains that the stunning animal you have just seen is a Whale Shark! A little while later, still in shock, you can’t believe your luck when an even bigger beast swims by. It is a majestic Gray Whale. Your guide proceeds to tell you all about the natural history of these gentle giants, who are both filter feeders that gorge on small plants and animals.
Wow! After the journey, you tell your friend how thrilled you are to have seen not one, but two members of this incredible family of aquatic creatures. “Whoa, not so fast”, says your friend. She tells you that these animals aren’t closely related at all! In fact, she explains, even though they both live in the ocean and have dorsal fins on their backs, sharks are remarkably different from whales. “How are they so different?!”, you beg to know.
You would not be alone in thinking that sharks and whales are alike. In fact, it’s easy to make that mistake, especially when there are confusing names like “Whale Shark” used for a fish, not a whale!
Since you’re so curious, let’s take a look at how sharks are different from whales. There are many interesting distinctions between these animals. Here are some of the main ones:
Comparing Sharks & Whales
Fish versus Mammals
Sharks are fish. They are vertebrates, meaning they have a rigid backbone. They are also very ancient beasts – this Class of aquatic animals has existed on the earth for more than 400 million years. They live in water and their bodies are covered in scales. To swim, they move their tails from side-to-side.
Whales on the other hand are mammals, a wholly different class of vertebrates. The history of these hairy creatures goes back about half as long as fish: they appeared on the earth about 180 to 200 million years ago. On an evolutionary time scale, whales are just babies, having appeared only about 50 to 60 million years ago! Compared to sharks, whales have smooth skin (no scales), and their tails move up-and-down for swimming.