How Big are Whales? - New Bedford Whaling Museum
Chart detailing the different sizes of whales

How Big are Whales?

How Big are Whales?

Cetaceans (whales, dolphins and porpoises) range in size and there are 88 species in all. This activity will help you explore the variety of sizes in this group of aquatic mammals.


  • A ruler, yard stick, or measuring tape
  • 100 ft. of rope, marked off in one foot (12inch) increments. You can also combine two or three smaller pieces of rope to achieve the full length of 100 feet
  • A piece of paper or the attached whale size chart to document your answers


  • You will gain a sense of scale as you compare the sizes of different species of whales to everyday items. ​

Guiding Questions

  • How big are whales?
  • How does the size of different whales compare with the size of common objects?


  1. Using a ruler, yardstick, or measuring tape, mark the rope in one foot increments (every 12 inches). To save time, you could mark the rope every five or ten feet.
  2. Now that your rope is marked, find a place (you may have to outside) where you have enough space to extend the rope to its full length.
  3. Using the whale size chart provided, place a book, a hat, a stick or some other object at the measurements along the rope that match up with the animals on the table. Can you see how big each animal is?
  4. Next, measure your height. Calculate how many of you it would take to equal the lengths of the whales listed in the table. Write those numbers in the chart or on your piece of paper.
  5. Next, look up the length of other objects, such as a school bus, a car, your favorite shirt, another animal, and calculate how many of that object it would take to equal the length of each of the whales.
  6. Now, fold the rope in half so that it is half as long. What species does this represent?
  7. Fold the rope in half again. Which species is this length?
  8. Fold the rope in half once more. You should now be at a length of 12.5 feet. What animal, or animals, does this represent?