What Animal Grows the Most Over Its Lifespan?

NWF Staff

Mar 01, 2010

Among live-born animals, the biggest grower would be the red kangaroo, which starts out about the size of a bean and weighs about 1 gram (0.03 ounces) but grows to 180 pounds—an increase of about 96,000 times its birth weight. Egg-layers do even better. The ocean mola, or sunfish, hatches from an egg about this big: o. It grows to 1,200 pounds and 10 feet long, an increase of about 60 million times.