The question of the world’s biggest lobster often leads to surprising answers, as the term “biggest” can refer to different measurements. Lobsters are marine crustaceans known for their robust size and are the largest arthropods by weight in the world. The species that achieves the greatest size is a subject of scientific record, providing a glimpse into the unique biology that permits such monumental growth.
Identifying the World Record Lobster
The undisputed heaviest marine crustacean ever documented is a specimen of the American lobster, Homarus americanus. This species, commonly known as the North Atlantic lobster, is indigenous to the cold waters of the North American Atlantic coast. The record-holding crustacean was caught off the coast of Nova Scotia, Canada, in 1977. This massive individual weighed 44 pounds and 6 ounces (over 20 kilograms) and measured approximately 3 feet, 6 inches in length. While most commercially caught American lobsters weigh only one to four pounds, this record demonstrates the species’ maximum size potential when allowed to live for an extended period.
The Biology Behind Monumental Size
The ability of American lobsters to reach such a colossal size is rooted in a biological process called indeterminate growth. Unlike many animals that stop growing once they reach maturity, lobsters continue to increase in size throughout their entire lifespan. This continuous growth is achieved through molting, where the lobster sheds its rigid, external exoskeleton to allow a new, larger shell to form underneath.
Molting is frequent in young lobsters, but it becomes much less common as they age, sometimes only happening once every few years for the largest individuals. A longer lifespan directly correlates to a greater potential for size, and these giants are estimated to be many decades old, sometimes over 100 years. Larger bodies offer advantages, particularly for females who can carry more eggs, contributing to reproductive success.
The molting process becomes increasingly difficult and energy-intensive as the lobster grows larger. The physical strain of shedding a massive shell can be fatal, and many older, larger lobsters die from exhaustion or complications during the molt. This difficulty ultimately imposes a natural limit on the maximum size a lobster can achieve. Environmental factors such as cold water, which slows metabolism, and a lack of predators also contribute to the survival required to reach these extreme weights.
Other Contenders for Largest Species
While the American lobster holds the record for weight, other species are notable for their dimensions, particularly those in the spiny lobster family. The European lobster (Homarus gammarus) is a close relative of the American lobster, sharing a similar body plan with large claws, and also grows to impressive sizes. However, the European species does not achieve the same maximum weights as its North Atlantic counterpart.
Spiny lobsters, also known as rock lobsters, are distinct because they lack the large, prominent claws that characterize the American and European lobsters. Species like the Caribbean spiny lobster (Panulirus argus) can grow up to 18 inches in length and weigh as much as 15 pounds. Other ornate spiny lobsters in the Indo-Pacific have been reported to reach lengths over six feet, including their very long antennae, though their total body weight is significantly less than the true lobsters.