Animals

Which Animals Never Stop Growing?

Most humans stop growing when they become a young adult, but what about other animals? Are there animals that never stop growing?

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A video of a what is believed to be the largest great white shark ever seen went viral earlier this month. While most great whites grow to be about 12 to 14 feet long (3.6-4 m), this shark--named Deep Blue--was 20 feet long (6 m)! Although some might find the idea of such a massive shark to be terrifying, some marine biologists see this as a good indicator of shark health. Sharks live on average for 73 years and can take up to 33 years to reach full size. Human's size is set from birth: we grow until we reach a genetically pre-determined size. Sharks keep growing until they die. Based on Deep Blue's size, scientists estimate her age is around 50 years old. A large sharks means that humans haven't killed it, and that they can breed longer.

Sharks aren't the only animal that keeps growing. Lizards, snakes, amphibians, and coral all continue to grow until they die. The scientific name for these creatures is "indeterminate growers". The Rocky Mountain bristlecone pine, like many other trees, lives for thousands of years and never stops growing. A 2001 study discovered one that hadn't had a significant mutation in its pollen or seeds over 4,700 years. At some point, the trees stop getting taller, but they will continue to thicken at the trunk as long as they have access to resources. Some animals have what's called "Negligible Senescence," which means they don't seem to age. Evolution didn't program a natural limit to their lives. Animals discovered to have this are tortoises, sharks, turtles, whales, and some types of fish. A Rougheye Rockfish was caught and determined to be 205 years old. Lobsters will continue growing until preyed upon or killed: A 20 pound (9 kg) lobster was discovered and believed to be 140 years old!

Learn More:

Do Great White Sharks Grow Forever? (Live Science)
"A marine scientist is dwarfed by what is being called the biggest shark ever caught on camera in a recent video taken near Mexico's Guadalupe Island. How did this 20-foot-long (6 meters) great white Internet sensation become such a behemoth?"

Why Do We Stop Growing? (NBC)
"Ultimately, we stop growing because we are genetically programmed to do so. It is our genes, made of DNA, that determine how we grow and develop."