Facts about the world of dolphins
The dolphin is one of the types of whales with small teeth, and there are more than 40 different species of dolphins; there are six types of them that can be called whales, including killer whales or pilot whales. Classes of oceanic mammals and this class divide into two prominent families, which are as follows:
- South Asian river dolphins, scientific name Platanistidae.
- In dolphins, whose scientific name is Inside.
- dolphin physical appearance
The dolphin has a streamlined body shape and has breathing gills and layers of grease necessary for thermal insulation; Adapted to live in the aquatic environment, the dolphin has a tail that moves up and down while swimming with a movement similar to the movement of the legs, and this means that the movement of the dolphin’s bottom is different from the movement of fishtails, which move sideways.
The dolphin lacks a strong sense of smell, as its body does not contain smell holes and olfactory nerves. The dolphin’s nose resembles a curved beak, and its nose is long and thin due to the shape of its long and prominent jawbones. As for the dolphin’s jaw, it contains a large number of conical teeth. Some species have up to 130 teeth in each jaw. Among the most famous types of dolphin with a prominent jaw are the following:
- Atlantic humpback dolphin.
- Bottlenose dolphin.
- Dolphin Toccucci.
- Spinner dolphin.
The anatomy of the front limbs of a dolphin is very similar to the anatomy of the front limbs of other mammals in terms of function. Still, the front limbs of a dolphin are short and rigid, and the pectoral fins use to direct and adjust the dolphin’s speed during its swimming. Some dolphins have this dorsal fin, such as cetacean dolphins of northern origin and dolphins of southern heritage.
The dolphin’s ears are in small openings located behind their eyes, and these openings do not connect to the middle ear. Some scientists believe that the sound is transmitted from the external ear openings to the centre and inner ear through fatty fats located behind the lower jaw and through various bones within the bones of the skull.
Where does dolphin live?
Dolphins live in oceans, seas, and rivers, and some species prefer to live in coastal areas, and others live in deep waters far from the coast. Most dolphins prefer to live in temperate, tropical regions; Because the dolphin classify as a warm-blooded mammal, which makes its presence in such areas better for it to regulate its body temperature.
One dolphin species lives in the North and South Pole, the orca dolphin; They are large-sized dolphins characterized by their ability to adapt to extreme cold and frozen water. That notes that river dolphins such as the Amazon dolphin and the South Asian dolphin are live in rivers and freshwater lakes. There are groups of dolphins that live permanently in freshwater rivers, such as Dolphin Toxic Guyana and Iowa.
Dolphins mating and breeding
The age of sexual puberty for a dolphin varies according to the type of dolphin, where it locat, and its sex; for example, female dolphins reach puberty between the ages of 5-13 years, and the age of puberty for males of dolphins ranges between 10-14 years. Dolphins are polyandrous creatures, and usually, Mating occurs among dolphins throughout the year and the rate of mating increases in some areas in the spring and autumn.
The gestation period of a female dolphin ranges from 9-17 months; for example, the gestation period of a female killer dolphin reaches 12 months, while the gestation period of a female orca dolphin reaches 17 months, and after the birth of the female of the young dolphin, she pushes it to the surface of the water for breathing and feeds the young dolphin On mother’s milk for up to two years, a baby dolphin can stay with its mother for as long as five years.
The dolphin is one of the active predators that depend for its food on a wide range of fish, squid, and marine crustaceans, and adult dolphins consume daily equivalent to 4%-6% of their weight in food. The consumption of food by a lactating female dolphin increases to approximately 8 % of its weight. The stomach of a dolphin divides into several sections, which speeds up the digestion process.
The foods that dolphins feed on vary based on the availability of these foods in the dolphin’s living environment and on the type of dolphin; As each type prefers certain kinds of fish as food for it, and where coastal dolphins like to eat fish and invertebrates found in the bottom, while marine dolphins eat fish and squid. Evidence indicates that oceanic dolphins dive to great depths in the sea up to 500 meters to get their food.
Communication between dolphins
The dolphin social network is a complex network, which includes a small number of young dolphins and their mothers, and dolphins share a relationship with a larger group of dolphins, moving simultaneously to hunt and obtain food, where one of the adult dolphins is responsible for organizing the movement of the group to obtain their prey by rotating on Swimming within the fish groups to be predated.
Dolphins rely on sound more than any other method in communicating between them, as the speed of sound transmission through water is faster than its transmission in air, and scientists believe that each dolphin makes its own sound whistle that represents a distinctive identification, and the dolphin uses this whistle to know the members of the group around it. and know their whereabouts.
The whistles released by dolphins maintain the continuity of vocal and physical contact between them. Dolphins often respond to the whistles of other dolphins by releasing whistles similar to them or by moving towards the place of the dolphin that issued the whistle. This is a method that adult dolphins also use when separated from their groups.
Threats to dolphin
Dolphin hunting by humans is the biggest threat and danger it faces. For centuries, dolphins have been a target for hunting in order to benefit from their meat, and many dolphins are usually exposed to fishing while heading to the surface for the purpose of breathing, and they fall into fishermen’s nets, and the dolphin faces another danger resulting from climate change that leads to disruption in the natural environment in which he lives; Climate change leads to an increase in temperatures and thus the transfer of food sources that dolphins depend on to deeper and colder waters, and marine heat waves negatively affect dolphin reproduction rates and their ability to adapt and survive.