The heaviest: the blue whale
The blue whale is the heaviest animal known to have ever lived, heavier than any dinosaur scientists have found. It is alive today, in oceans around the world, and it eats some of the smallest animals in the sea.
Being in the sea helps it be so big. The water holds up its weight, so it doesn't need legs strong enough to carry it. On land, an animal that heavy would need enormous legs, like pillars.
The longest: maybe a long-necked dinosaur
The giant plant-eating dinosaurs called sauropods had long necks and longer tails. A few of them, like Argentinosaurus, may have been longer than a blue whale from nose to tail. They were lighter than the whale for their length, because so much of them was neck and tail.
Here is the catch: no one has found a whole skeleton of the biggest sauropods. Scientists work out their size from a few huge bones, like a backbone or a leg bone, by comparing them with smaller cousins whose whole skeletons are known. That makes their lengths and weights estimates, and two scientists can give different numbers for the same dinosaur.
The giants, side by side
Here are the biggest animals on Peabody, the living ones and the ones that lived long ago, with their numbers and where each number came from. A dinosaur's numbers are scientists' estimates from its bones.
| Animal | Length (or height) | Weight |
|---|---|---|
| 🐋 Blue whale | 110 ft34 m1 | 165 tons150 tonnes1 |
| 🦕 Argentinosauruslived long ago | 120 ft37 m2 | 110 tons100 tonnes2 |
| 🦕 Diplodocuslived long ago | 80 to 92 ft24 to 28 m3 | 15 tons14 tonnes4 |
| 🦕 Brachiosauruslived long ago | 75 ft23 m5 | 66 tons60 tonnes6 |
| 🦕 Brontosauruslived long ago | 69 ft21 m7 | 30 tons27 tonnes7 |
| 🐋 Sperm whale | 40 to 52 ft12 to 16 m8 | 15 to 45 tons14 to 41 tonnes8 |
| 🦈 Whale shark | 40 ft12 m9 | 40 tons36 tonnes9 |
| 🐘 African elephant | 13 ft4 m10tall | 6 tons5.4 tonnes10 |
| 🦒 Giraffe | 18 ft5.5 m11tall | no checked number yet |
The biggest on land today
The biggest land animal alive now is the African elephant, and the tallest is the giraffe. Both would look small beside a blue whale or a giant sauropod. Open Compare Two and stand any two of them side by side, with you beside them, to see how big the difference really is.
For Big readers: why aren't animals that big any more?
Big land animals need a lot of food and space, and being huge takes a very long time to grow into. Scientists have ideas about how the giant sauropods grew so big: light bones with air inside, lungs a bit like a bird's, and laying many eggs instead of raising one big baby at a time. In the sea today, the blue whale eats tiny shrimp-like animals called krill by the mouthful, which is one of the few ways to feed a body that big.
Scientists keep finding new giants, and they argue about how heavy each one was. That's how science works: when someone digs up a bigger bone, the record can change.
Pick Big at the top to see the part for older readers.