New research has provided surprising details about the biology of Earth’s largest fish, the whale shark. Scientists say that female whale sharks grow more slowly but reach a much larger size than males.

Males were found to grow faster than females. They reached around eight meters in length at about 30 years old. At that age, they reach sexual maturity, meaning the fish were able to produce young. Females grew larger than males. Females reached about 14 meters at about age 50, when they reached sexual maturity.

Mark Meekan, a marine biologist at the Australian Institute of Marine Science,  described whale sharks as “remarkable.” He noted that females give birth to many young: “up to 300 at one time.” For this reason, Meekan said, female sharks probably need to be very large.

Whale sharks are filter feeders, meaning they take food and nutrients from the water. They swim great distances to find enough to eat.

The longest-known whale shark ever recorded reached a length of about 18 meters. Whale sharks can live for 100 to 150 years.

Meekan suggested the study’s findings were important for saving whale sharks. He noted that if it takes 30 or more years for the creatures to reach sexual maturity, “there are lots of threats such as hunting and ship-strike…before they get a chance to breed.”