The Galapagos shark is a very strong fish and an active swimmer that surprises with its large size. It is considered a very curious species, since it frequently approaches divers and boats, and in rare occasions it is dangerous for humans, if it feels in danger, it would make sudden movements that would immediately alert those who are at a considerable distance.
Despite its name, it is not only possible to find the Galapagos shark in this archipelago, but it can be found in tropical waters all over the world. Its name comes from the fact that it was first identified in the Galapagos in 1905.
The Galapagos shark is considered a strong fish, an active swimmer, either alone or in groups, a specimen capable of crossing the open sea, and between islands. There are those who have spotted it within 50 km of land, but younger specimens rarely venture further than 25 meters. In terms of depth, there are records of adults venturing down to 180 meters.
Among the approximately 400 species of sharks that have been described, the Galapagos is considered a large cartilaginous fish, measuring up to 3.7 meters in length and living from 20 to 25 years. The maximum recorded weight is 85.5 kg.
The most common shark species around the archipelago were Galapagos, hammerhead, blacktip and whitetip, which represent 83% of the sharks identified. These species occupy similar habitats, so they are usually found together.
They are often found abundantly in shallow waters of the Galapagos Islands. It can also be found in temperate oceanic or coastal waters. It has an acute sensitivity to vibration and electrical conductivity.
Its body is slender and streamlined, torpedo-shaped, slender and rounded nose, the snout is broad and rounded. The eyes are round and medium-sized. The mouth has 14 rows of teeth on each side of both jaws. The upper teeth are strong and triangular and the lower teeth are narrower. Both have serrated edges.
It has two dorsal fins, the first is high and sickle-shaped, at the level of the pectoral fin. The second originates a little beyond the height of the anal fin. The pectoral fins are large and pointed.
On the other hand, the color of the upper body is brownish gray or brown, and below is generally white or light. It also has white stripes on the sides.
This curious animal has a body that ranges from black to light gray. This characteristic allows it to recover its body heat after getting out of the sea. It is also capable of slowing down its heartbeat while swimming so as not to decrease its body heat levels.
However, the colors of the adult males vary by season; the species found in the South Islands have greenish and reddish shades, those inhabiting Santa Cruz Island black and reddish and those of Fernandina Island dark greenish and brick, while the juveniles have a rather light dorsal stripe.
Don’t be fooled by their sharp claws. Marine iguanas, although they look like fierce predators, have a herbivorous diet and their diet is mainly based on seaweed. Iguanas swim mainly because the sea is where they get their food. The shape of their mouth is part of the adaptation that iguanas have to feed on the algae in killer whales. Likewise, their claws are there to hold on tightly while they eat and prevent the current from moving them.
Marine iguanas can hold their breath for more than 45 minutes.
They are expert swimmers, thanks to the membranes they have in their toes. According to experts, the Galapagos marine iguana has the same origin and ancestor as the iguanas that move on land, but this is an evolution and it is because they can move easily in the sea. On the other hand, when they leave the water they become somewhat clumsy.
Iguanas reproduce oviparously, that is, they lay eggs to reproduce their young. If iguanas are anything like humans, it is that a good scent is very important on the first date, since females choose the male with the best scent to reproduce, which is a crucial part of the mating ritual of Galapagos iguanas.
In addition to scent, males will use bright colors on their skin to attract females. Also the color of the iguanas can vary depending on their location.
They feed on marine plants and algae. Contrary to what you might think by looking at its body and its huge sharp claws, this animal does not consume meat of any kind. In cases of scarcity of marine plants, it consumes terrestrial plants without any problem.
They are quite territorial animals, they do not like to share their living space, as they consider it a threat to their survival. Males tolerate females, as long as there is enough food, otherwise they will not allow them to stay.
Marine iguanas sleep at night in burrows and it is very common a cooperative behavior between Darwin’s finches and iguanas as they stretch their bodies and let the finches remove their ticks, this scene is a great spectacle to watch.
Regarding the predators of the Galapagos marine iguana, it has been proven that their proximity to humans on the island makes them vulnerable to feral cats and dogs, and many humans harm and kill them, sometimes even for sport.
The fact that these little animals live constantly in and out of the sea also generates inconveniences for them. Many Galapagos marine iguanas get entangled in fishing nets, and the plastic debris they leave on the beaches causes damage and even death. Similarly, boats located in shallow areas cause the death of Galapagos marine iguanas.
If you ever find an iguana spitting, do not panic, they do it to eliminate sea salt, thus protecting their organism from excess salt.
The marine iguana was the animal that inspired naturalist Charles Darwin, and today they are a phenomenal laboratory for scientists to study the phenomenon of speciation. This animal has seven subspecies, which live in territories far from each other, and can still reproduce with each other.
In his time Charles Darwin referred to this species as “clumsy and disgusting”, but the truth is that if this remarkable naturalist had known the marine iguana as it is known today he would retract his words. It is truly an animal full of interesting, uncommon and impressive characteristics that make it a unique species that all humans should respect and protect.