The Galapagos Shark of San Cristóbal Island (Carcharhinus Galapagensis)
- The Persaud Catalog
- Aug 10
- 7 min read
This month's article series shall discuss the esteemed & magnificent San Cristóbal Island / Chatham Island! San Cristobal Island is a part of the Galapagos Islands Archipelago, located in the southern Pacific Ocean.
Out of all the Galapagos islands, San Cristóbal Island is the farthest east. San Cristobal Island is located approximately 501.75 nautical miles (577.403588 miles or 929.241 kilometers) off the central coast of Ecuador. Though San Cristobal Island is not the main Galapagos island, it is one of two islands with an airport. It is the fifth largest of the 127 Galapagos islands. The island has a very low population, with only about 6,000 inhabitants.
The island is extremely biodiverse, & has vibrant marine ecosystems that are directly connected with the towns around them. Many consider the sea lions that live on the beaches, walkways, & park benches to be locals. The majority of the beaches, as well as coastal walkways on the island, have these marine mammals on them. Aside from the Sea Lions, San Cristobal Island has a variety of other interesting marine species to offer. One of these species is the Carcharhinus Galapagensis (Galapagos Shark).
The Galapagos Shark is a species of reef shark found in various tropical settings, in both the Atlantic & Pacific Oceans. This species is very similar in appearance to a few other species of large reef sharks, making it very hard to distinguish between them.
The Galapagos Shark is very rarely found in intertidal zones, & usually stays in open oceanic coral reefs. While diving, one may find these sharks at depths of 20 to 590 feet (6.096 meters to 179.832 meters) deep. Usually they are found alone; however, they are known to form large groups around inlets & seamounts.
In this article, we will discuss the discovery & life of the Galapagos Shark, the mating strategies, practices, procedures, tactics, & cycles of the Galapagos Shark, the distribution of the Galapagos Shark, & the scientific details of the Galapagos Shark. With that being said, let us delve into this beautiful requiem shark.
The Discovery & Life Of The Galapagos Shark
The Galapagos Shark was discovered by Robert Evans Snodgrass, an American entomologist, & Edmund Heller, an American zoologist. It was discovered in the year 1905. The evolutionary history of the Galapagos Shark is very unclear. It is estimated that they have existed since at least the early Cretaceous period.
The Galapagos Shark reaches a maximum of 11 feet (3.3528 meters) long. Additionally, it reaches a maximum of 418.878 pounds (190 kilograms). The lifespan of the Galapagos Shark is 20 to 24 years.
The intelligence of the Shark is understudied; however, what is known is that they are not playful. Though they are considered to be potentially dangerous, it is extremely unlikely that they will attack a diver.
As of 2025, Galapagos Sharks are under pressure from the fishing industry, as many local fishermen like to catch & eat them. This is why the localized population in the Galápagos Islands is aggressive towards boats, as well as people. Currently, this species has caused 1 fatal shark attack to a diver in the Virgin Islands. This species is not known to be territorial, though there is a clear hierarchy between the various sharks. Galapagos sharks are solitary animals, only forming groups when they are in a frenzy.
Sharks, in particular, can swim by flexing themselves side to side, which propels them forward. They steer themselves using their pectoral & dorsal fins. With these adaptations, they can move through the water column with ease. The average speed of the Galapagos shark is 3.2 kilometers per hour (1.98839 miles per hour).
Unlike the majority of fish, sharks do not have swim bladders. Instead of using swim bladders to control their buoyancy, their livers have extra oil in them.
Galapagos Sharks are only able to sleep by shutting off half of their brains, & continuing to swim. They usually sleep close to the sea floor.
Galapagos Sharks usually have a diet of crustaceans, molluscs, fish, & occasionally small sea lions. Since they swim so close to the bottom, they often feast on bottom dwellers. These bottom dwellers can range from octopi & squid to eels & triggerfish. They are cannibalistic, & are known to occasionally eat their pups. For this reason, the pups will purposely stay in shallower water. Unfortunately, we do not know how much they eat per day, nor do we have any information on their metabolism.
These sharks hunt diurnally, & hunt seemingly whenever they can. They locate their food through sight, & ripples in the water. Galapagos Sharks function as predators in the coral reef ecosystem. This species of shark has very few natural predators, aside from local fishermen.
The Galapagos Shark is light grey, with a white underbelly. Their upper tail fin is elongated, & their snout is slightly rounded. They are often mistaken for the grey reef shark, as well as the dusky shark.
The IUCN Red List has assessed this species, & has thankfully given it the ranking of Least Concern.
The Mating Strategies, Practices, Procedures, Tactics, & Cycles Of The Galapagos Shark
The Galapagos Shark breeds via sexual reproduction. Galapagos Sharks are not hermaphroditic, & have two distinct sexes. Additionally, they are viviparous, meaning that they are live-bearing. These sharks are considered to be polyamorous, meaning both males & females have multiple partners.
In the Galapagos Islands population they are known to breed around the eastern parts of the Archipelago. Both females & males will sexually mature at the age of 10 years. Unfortunately, very little information on their breeding habits is available, so it is unclear what the exact breeding ritual is like. The females will initiate the ritual by releasing a chemical into the ocean.
Once the ritual is complete, the males will have no part in the pup's life. Their gestational period lasts approximately 1 year, & each pregnancy yields 4 to 16 pups. Once the pup is born, the mother will most likely not have another litter for another 2 to 3 years. These pups will be 16 to 32 inches (40.64 to 81.28 centimeters) long at birth. More often than not, the pups will be forced to stay away from their parents, & are given little to no care.
The Distribution Of The Galapagos Shark
Galapagos Sharks are found in various island chains around the world, & rarely migrate between them. These island chains are Bermuda, the Virgin Islands, Cape Verde, Ascension Islands, Saint Helena, the Galapagos Islands, Walter’s Shoal, São Tomé Island, & the Hawaiian Islands.
The Galapagos Shark is found no deeper than 82 feet when they are juveniles, & as adults are found as deep as 919 feet. This species is not migratory at all. They tend to swim at the bottom of the ocean, near patches of loose substrate.
The Scientific Details of The Galapagos Shark
By far the most interesting thing about this shark is their large teeth. The Galapagos Shark has 14 large, serrated teeth that are triangular. These teeth are incredibly sharp, & will cause large amounts of damage if they were to bite. Their lower teeth are much narrower, & point straight up with a small base instead of being triangular.
Galapagos Sharks are known to have 1 major parasite, which is known as Dermophthirius Carcharhini. This parasite is a species of worm that causes massive infections in these sharks, & can cause loss of scales. In addition to the loss of scales, the worm can cause the death of the shark.
Unlike most requiem Sharks, the Galapagos Shark has a mere 58 vertebrae. Their skeleton of this shark is largely cartilaginous, which helps them to swim.
Their phylum is Chordata, meaning that they developed these 5 characteristics. All species under the phylum of Chordata develop 5 similar characteristics either in adulthood or as juveniles. The characteristics that they develop include, a notochord, dorsal hollow nerve cord, endostyle or thyroid, pharyngeal Slits, & a post-anal tail. & three middle ear bones.
Their class is Chondrichthyes. This is a class of fish that is primarily composed of cartilage. This class can be compared to the class Osteichthyes, which is a class of fish that is primarily composed of bone. A few universal characteristics for any fish in the class Chondrichthyes are that they are all jawed vertebrates, they have paired fins, paired nares, scales, & a heart with chambers in a series.
Their order is that of Carcharhiniformes. This order has approximately 270 species categorized under it, & is characterized by two dorsal fins, anal fins, & five gill slits.
Their family is that of Carcharhinidae, which are commonly known as requiem sharks. The majority of these sharks are found in tropical areas. This family of sharks has existed since at least the Valanginian age.
Their genus is that of Carcharhinus. Currently, there are 35 different species categorized under this genus. Their binomial name is currently Carcharhinus Galapagensis.
Directories / Credits
Citation No. 1: “Carcharhinus Galapagensis” Written By Unknown & Published at an Unknown Date. Published by Florida Museum. Retrieval Date: December 8th, 2023.
Citation No. 2: “Galapagos Shark” Written By Unknown, & Published at an Unknown Date. Published by Shark Guardian. Retrieval Date: December 8th, 2023.
Citation No. 3: “Galapagos Sharks” Written By Unknown & Published at an Unknown Date. Published by the Galapagos Conservation. Retrieval Date: December 8th, 2023.
Citation No. 4: “Galapagos Shark: Carcharhinus Galapagensis” Written By Unknown & Published at an Unknown Date. Published by AZ Animals. Retrieval Date: December 8th, 2023.
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