Sharks belong to a group of fish characterized by a cartilage skeleton, five to seven pairs of gill slits on the sides of the head, and pectoral fins that are not fused to the head. With over 500 known species, sharks display a stunning diversity in size, shape, coloration, habitat, and behavior.
Sharks inhabit all oceans and range from small, sluggish bottom dwellers to large, powerful apex predators. The variation across species also applies to one of the most basic physical traits, their weight. In this article, we will look at what influences shark weight, which species grow the largest, and an overview of the size of different shark species.
How Sharks Look Like
Sharks are large bulky fishes with a blunt torpedo body shape; they are characterized by their sharply pointed conical snout, large pectoral and dorsal fins, and a strong crescent-shaped tail. The distinctive white color of their belly is worth mentioning.
Sharks have a contrasting pattern of dark blue, gray, or brown on their back and sides. They are good hunters endowed with strong muscles, good eyesight, and a keen sense of smell. In addition, their massive jaws are armed with large sharply pointed, coarsely serrated teeth. The teeth are built to cut flesh, easily puncture, and shatter bone.
How Shark Weight is Measured
Since sharks live underwater, weighing them poses some unique challenges compared to land animals. Scientists have developed several techniques for measuring shark weight accurately.
For deceased sharks, the most straightforward method is to haul the shark onto land and weigh it on a scale. However, sharks are rarely captured and killed solely for weighing. Most weight data come from sharks caught in commercial fishing operations or sharks that died naturally and washed ashore.
Weighing live sharks requires more creative methods. One technique is to catch a shark in a net, lift it out of the water using a crane scale, and then quickly weigh it before release. However, this can stress the shark significantly.
A better alternative is to use non-invasive buoyancy weighing. Scientists place a sedative in the water to calm the shark. Once sedated, they attach floats to the shark to determine its buoyancy and obtain an estimate of weight based on its displacement of water. This method minimizes stress.
Shark Weight by Species
Shark weights can fluctuate significantly throughout their lifetimes and species. When first born, shark pups typically weigh just a few pounds. As they grow, most shark species will gain hundreds or even thousands of pounds before reaching adult size.
Once fully mature, an individual shark’s weight may remain fairly steady or continue to gradually increase over time. Different shark species can vary dramatically in their average adult weights. Here are some examples:
- Whale Sharks: Adults can grow to 45 feet in length and weigh about 41,000 pounds.
- Great White Shark: Typical adult weighs 700 – 1,100 pounds (317-500 kg) and can grow up to 16 feet in length.
- Tiger Shark: Adult can reach up to 12 feet in length and weighs about 850-1,400 pounds (385-635 kg).
- Bull Shark: Adults usually weigh 200-290 pounds (90-130 kg) and can grow up to 11 feet in length.
- Hammerhead Shark: An adult hammerhead weighs 160-300 pounds (73-136 kg) reaching an average length of 13.1 feet.
- Nurse Shark: Full grown nurse sharks weigh 150-330 pounds (68-150 kg) and can grow up to 7.5 to 9 feet in length.
- Blacktip Shark: Adult can grow as long as 8 feet and weigh between 60 – 250 pounds (27-113 kg).
- Leopard Shark: Typical adult weight is up to 41 pounds.
- Spiny Dogfish shark: These small sharks can reach only 3 to 4 feet in length and weigh around 10 pounds as adults.
The largest shark species far outweigh the smallest sharks. Even within a species, older and bigger sharks can be much heavier than younger ones. However, these examples give a general idea of average adult weights across different types of sharks.
Factors Influencing Shark Weight
A shark’s weight is dependent on several key factors including age, gender, habitat, and species.
1) Age: As sharks age, they typically increase in size and weight. Older sharks weigh bigger than baby sharks.
2) Gender: Many shark species exhibit sexual dimorphism; female sharks tend to be larger than males.
3) Habitat: Habitat also plays a role as sharks that live in nutrient-rich waters with abundant prey tend to be heavier than sharks living in less optimal conditions.
4) Species: The biggest determinant of shark weight is the species. Shark species range dramatically in maximum size and weight. The largest shark species such as the whale shark can weigh over 40,000 pounds, while the dwarf lantern shark weighs less than two pounds.
Shark weights vary greatly both within and between species. Most fully grown sharks weigh between 1,500 and 4,000 pounds (680 and 1,800 kg), but some weighing more than 2,270 kg (about 5,000 pounds) have been documented. Factors like age, sex, habitat, and diet all influence shark size and weight.