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Majestic Marine Mammals – A Quick Quiz

By Gabrielle Bentley and Ariel Marcy, 20 July 2023

These warm-blooded, birth-giving, milk-making mammals make their living out at sea. Sea if you can score a dive out of five… while we won’t hold our breath, the marine mammals will!

#1. Which land animal is most closely related to whales?

Incredibly, blue whales evolved from land animals. Their closest living land animal relatives are hippopotamuses.

#2. True or false? Orcas are classified as dolphins.

True. Orcas are part of the Delphinidae family, also known as the oceanic dolphins. This family includes the bottlenose dolphins. Orcas are the largest member of the family, weighing 10 metric tons.

#3. Which of the following orca facts is actually a myth?

In the wild, orcas don’t usually attack humans and in some instances have been known to protect human divers from other threats. Recently, a small group of orcas have been attacking sailing ships off the coast of Spain. Experts think that one orca got hurt by a boat and has been teaching other orcas to attack boat rudders.

#4. Seals and dolphins have many adaptations to live in the sea. Which of the following is NOT seen in seals and dolphins?

Unlike fish, marine mammals move up and down when they swim. That’s why their tails and rear flippers are sideways, while fish tails go up and down.

#5. How many blue whales are alive today?

Even though people stopped hunting blue whales more than 40 years ago, their populations are still recovering. 10,000 whales might sound like a lot, but humans killed over 350,000 blue whales in the early 20th century.

Was I right?


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  1. We love your quizes, but your answer to question 2 is incorrect!
    Yes, Orcas are dolphins, but dolphins are whales too.
    So, Orcas actually ARE classified as whales.
    It’s like asking if a goanna is a reptile or a lizard – it’s both!.

    1. Ooh! Good point!
      The original question is whether orcas are whales.
      I’d feel a bit bad saying that they are whales, but as you say, they technically are.
      We’re changing the question to be less tricky.


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