In previous articles we talked about White shark as one of the fiercest predators on the seas. Today we come to tell you another about sharks. In this case we are going to talk about bull shark. Although in principle this name does not sound very common, it is one of the most common sharks that inhabit the coasts and oceans of Latin America. Its scientific name is Carcharhinus leucas.
If you want to know all the characteristics, eating, the habitat y reproduction about this shark, this is your post.
Key features
There are numerous sightings of this shark in many places. It has great ease of movement by sea and are quite numerous. It can navigate both by fresh and salt water and both by rivers and lakes of Central America and the Amazon.
your body has two large dorsal fins and an elongated tail with a long upper lobe and a precaudal beak. Specimens of up to about 3,2 meters long. On average, males measure 2,1 meters and females 2,2 meters, with females generally somewhat more robust. Their coloration is gray on the dorsal part y white in the ventral area, a pattern that aids camouflage in coastal and murky waters.
It is a marine species with a reputation for determined character and is considered among the largest shark species in shallow areas. Its weight ranges between 90 and 200 kilograms or more in exceptional individuals. It is often mentioned along with the great white and tiger sharks as one of the sharks involved in incidents with humans, largely due to its preference for waters close to the coast where there is human activity.
Its body is robust, with relatively wide pectoral fins and a short, blunt snout. Juveniles may show diffuse dark spots in fins, which disappear as they grow. As for their dentition, they have wide, triangular, serrated teeth, designed to cut large prey; the bite is very powerful and the jaw, muscular. It has nictitating membranes that protect the eyes during the attack.
It usually manifests intense activity and opportunistic behavior. When hunting, they can circle and quickly charge at their prey, taking advantage of the low visibility of estuaries and surf. Due to their habit of using shallows, extreme caution should be taken in breeding areas and river mouths.
Important clarification: two species called "bull shark"
In Spanish, the common name bull shark It is also used to designate Carcharias taurus, known internationally as sand tiger shark or sand tiger shark, and in some places called the grey nurse shark. This species, unlike the subject of this article, belongs to another family and shows very characteristic features such as long, thin teeth that protrude even with the mouth closed, cave congregations, and a peculiar way of regulating buoyancy. In this article, we focus on Carcharhinus leucas (bull shark), the true bull shark of euryhaline habits.
This clarification is relevant because the intrauterine cannibalism is typical of Carcharias taurus, do not give Carcharhinus leucas. Later we detail the correct reproduction of the bull shark that is the subject of this sheet.
Distribution and habitat
We can find the bull shark in the Amazon River in South America, the Zambezi (which is why it is also called the Zambezi shark) and the Limpopo in Africa, in the Lake Cocibolca (Nicaragua) and the Ganges, in India.
Regarding their habitat, these animals love to move around areas near beaches and coasts. This way, they can find a greater number of prey to feed on. These sharks are found along the tropical and subtropical coastal areas of the world, in the Pacific, Atlantic and Indian Oceans, and frequently penetrate estuaries, lagoons and rivers with murky waters.
They are animals that generally show loyalty to breeding and feeding areas during key stages of their lives. However, they can perform considerable displacements between coastal and river systems. Upstream incursions have been documented. long distances, using river corridors to exploit freshwater resources.
Juveniles employ natural nurseries in bays, estuaries and estuaries, where shallow, turbid water offers refuge from larger predators. Adults can move between 0 and 150 m depth on a regular basis, although most human interactions occur within 30 m.
This shark's ability to tolerate fresh water allows it to maintain resident populations In certain systems (such as Lake Nicaragua), alternating with periodic outflows to the sea. dam construction and other barriers can disrupt their routes and affect their historical distribution.
Bull shark feeding
The bull shark feeds on all types of marine damsSuch is their breadth of diet, that they are able to eat other sharksTheir diet is entirely carnivorous. They are dangerous to humans, since the area where they hunt is very close to bathing areas.
Include in your diet bony fish, stripes, other small elasmobranchs, squid, large crustaceans and even young turtles, seabirds or carrion when available. In rivers and lakes it can consume freshwater fish and crabs, showing a marked trophic opportunism.
Hunting usually intensifies when dawn and dusk, and takes advantage of the turbidity of the water to approach at close range. It has a highly developed sensory system: lateral line to detect vibrations and Lorenzini ampoules to capture electric fields from their prey.
The ability to move between fresh and salt water is not due to a single gland, but to a set of physiological mechanisms which include changes in the kidney (reduction of urea excretion in freshwater fisheries), liver (reserve of osmotically active compounds), the rectal gland (excretion of salts in marine environments) and adjustments in the gillsThis osmotic plasticity, extraordinary among sharks, explains why the bull shark can frequent estuarine and river waters where many other species would not survive.
In areas with human activity, poor disposal practices and feeding can modify their feeding behavior, so feeding wildlife is not recommended and a responsible management of fishing waste.
Behavior and movements
The bull shark alternates periods of slow swimming and patrolling near the bottom with rapid accelerations to capture prey. It can be found alone or in small groups, especially in areas with high food availability.
It presents behaviors of seasonal residence in bays and estuaries that function as nursery areas. In certain regions, pregnant females regularly use the same birthing sites, showing spatial fidelity.
In temperate latitudes it tends to perform seasonal movements following warmer waters, while in tropical areas its distribution may be more stable. It is capable of ascending rivers for hundreds or thousands of kilometers and stay there for long periods if conditions permit.
His reputation for being aggressive is explained more by the overlap with humans in shallow waters than by a higher intrinsic aggressiveness. Most negative interactions are associated with reduced visibility, baiting or presence of prey near bathers or fishermen.
Reproduction and offspring
This shark is known to present high levels of testosterone during mating season and may display behaviors territorial marked. This may intensify their presence in key breeding and feeding areas.
Unlike the shark also called "bull" in other contexts (Carcharias taurus), the bull shark Carcharhinus leucas It is placental viviparousAfter an initial embryonic development, the yolk sac transforms into a placenta that nourishes the embryos until birth.
Females possess two uteruses (characteristic of many elasmobranchs), but in this species intrauterine cannibalism does not occur. gestation usually lasts around 10–11 months and the litters can be of 1 to more than 10 offspring, depending on the size and condition of the mother. In many populations, females give birth every two years, a relatively slow reproductive rate compared to bony fish.
The young are born in estuaries, lagoons and bays of low salinity that act as day care centers, where turbidity and shallow depth reduce the risk of predation. The hatchlings measure in the order of several tens of centimeters and are totally independent at birth, occupying very shallow waters during their first years.
Sexual maturity is reached after several years, with females taking longer than males to reach reproductive size. The combination of relatively slow growth and low recruitment rates make the species vulnerable to overexploitation.
Threat category
This species is not listed as endangered by the International Union for Conservation of Nature, but it is considered globally threatened by targeted fishing and the bycatch in coastal arts. In some regions, their status may vary, with populations more depleted than others.
When they are in areas close to humans they are more vulnerable to fishery and environmental changes that are associated with habitat modification. The construction of prey, contamination agricultural and industrial, dredging and loss of mangroves reduce the quality and availability of breeding and feeding areas.
Traditionally, bull sharks are commercially fished for sale. leather, carne y liver oil, And its fins have boosted demand in several fisheries. Effective management requires catch limits, protection of nurseries and measures to reduce bycatch, along with controls on international trade and genetic monitoring of populations.
La environmental education, beach management and responsible coexistence In areas of high recreational use, these observations are key to reducing conflicts. In areas where citizen science programs have been implemented, sighting data help guide conservation efforts.
Videographer: https://www.youtube.com/watch?v=V6N-acGU-OI
With this information, you'll be able to learn more about these sharks, considered the most dangerous to humans. Correctly distinguish What species is behind the name “bull shark”?, understand your euryhaline biology and risk factor's that they face on coasts and rivers is essential to improve both safety at sea and coastal and river conservation strategies.