Dolphins are highly intelligent marine mammals and are part of the family of toothed whales that includes orcas and pilot whales. They are found worldwide, mostly in shallow seas of the continental shelves, and are carnivores, mostly eating fish and squid. Dolphin coloration varies, but they are generally gray in color with darker backs than the rest of their bodies. According to wikispecies, there are 41 species of dolphins of the family delphinidae or oceanic dolphins. Diet Dolphins consume a variety of prey including fish, squid and crustaceans.
Population
It is difficult to estimate population numbers since there are many different species spanning a large geographic area. Range Most species live in shallow areas of tropical and temperate oceans throughout the world. Five species live in the world's rivers. Behavior Dolphins are well known for their agility and playful behavior, making them a favorite of wildlife watchers. Many species will leap out of the water, spy-hop (rise vertically out of the water to view their surroundings) and follow ships, often synchronizing their movements with one another.
Scientists believe that dolphins conserve energy by swimming alongside ships, a practice known as bow-riding. Dolphins live in social groups of five to several hundred. They use echolocation to find prey and often hunt together by surrounding a school of fish, trapping them and taking turns swimming through the school and catching fish. Dolphins will also follow seabirds, other whales and fishing boats to feed opportunistically on the fish they scare up or discard. Reproduction Mating Season Throughout the year, though in some areas there is a peak in spring and fall.
Gestation 9-17 months depending on the species. When it is time to give birth, the female will distance herself from the pod, often going near the surface of the water. Number of offspring Usually one calf; twins are rare. As soon as the calf is born, the mother must quickly take it to the surface so it can take its first breath. The calf will nurse from 11 months to 2 years, and after it is done nursing it will still stay with its mother until it is between 3 and 8 years old.
Dolphin Life Cycle Facts About the Dolphin Life Cycle & Birthing Process
The dolphin life cycle begins at birth; like other mammals a dolphin will give birth to live babies as apposed to laying eggs that will later hatch. Although there are several breeds of dolphins, their life cycle is about the same. Dolphins are one of the most intelligent mammals in existence, not only are they social animals, but they can interact with humans to a point, and have even been known to save a human’s life if lost at sea. These sea creatures have fascinated people since their discovery, and they are no less fascinating now. The dolphin life cycle actually begins with the reproductive cycle.
For a mammal to give birth is no easy accomplishment, but it can be very difficult to do at sea, which is how dolphins must give birth. After dolphins mate the female’s pregnancy will last between 11 to 12 months. The exact length of the pregnancy depends on the species of dolphin; while some will be pregnant for 11 months, others will carry their baby for up to 1 year. When a dolphin is born it will be born tail first; the babies will know how to swim as soon as they are born. In most cases a dolphin will stay with the group it was born in, even after it reaches maturity.
This is usually the mother’s group. As part of the dolphin life cycle it will reach sexual maturity at about 7 to 12 years of age for a female and 10 to 15 years of age for a male. The exact age varies on species and the region of the world that they inhabit. Dolphins do not stay with the same mate throughout their lives so there may be many different mates during a dolphin life cycle. A female will usually give birth about every 4 or 5 years. A dolphin may have up to 11 calves in her lifetime, mating up until she reaches her 40s.
The reason there is so much time between births is because a dolphin female will care for her young for quite some time before they will let the calf take care of itself. One of the most interesting things about the birth process of a dolphin is in how much it resembles the birth process of humans. When a female dolphin is ready to give birth another female dolphin will be present to help her with the birth; she is sort of dolphin midwife. After the dolphin is born they will help it to the surface so that it can take its first breath of air. When a female dolphin begins the birthing process she must be very watchful for predators.
It will take about 3 hours for her to give birth, and during this time there will be blood, just like there is with humans. This will of course attack one of the dolphin’s biggest enemies, sharks. To help the mother while she is giving birth the other dolphins in her group will form a circle around her to try and keep her safe from predators while she is giving birth. Just like human babies, dolphins will drink milk from their mother, but feeding underwater can be a little difficult. It is for this reason that the dolphin has evolved in a way that helps them nurse their young underwater.
The female dolphin can actually squirt her milk into the mouth of her baby. Depending on the species of dolphin, the dolphin life cycle will begin at birth and last until they are between 35 and 55 years old, with most females not living too much past their reproductive years. Dolphins are marine mammals closely related to whales and porpoises. There are almost forty species of dolphin in 17 genera. They vary in size from 1. 2 m (4 ft) and 40 kg (90 lb) (Maui's dolphin), up to 9. 5 m (30 ft) and 10 tonnes (9. 8 long tons; 11 short tons) (the orca or killer whale).
They are found worldwide, mostly in the shallower seas of the continental shelves and are carnivores, eating mostly fish and squid. The familyDelphinidae, the largest in the Cetacean order, evolved relatively recently, about ten million years ago during the Miocene. Contents
Etymology The name is originally from Greek ? (delphis), dolphin,[1] which was related to the Greek ? (delphus), womb. [2] The animal's name can therefore be interpreted as meaning a 'fish' with a womb. [3] The name was transmitted via the Latin delphinus[4] (the romanization of the later Greek ? – delphinos[5]), which in Medieval Latin became dolfinus and in Old Frenchdaulphin, which reintroduced the ph into the word.
The term mereswine (that is, sea pig) has also historically been used. [6] The term 'dolphin' can be used to refer to, under the suborder odontoceti, all the species in the family delphinidae (marine dolphins including orcas and pilot whales) and the river dolphin superfamily Platanistoidea, which includes the families Iniidae (Amazon river dolphin), Lipotidae (Yangtze river dolphin) and Platanistidae (Ganges river dolphin and Indus river dolphin). [7][8]
This term has often been misused in the US, mainly in the fishing industry, where all small cetaceans (dolphins and porpoises) are considered porpoises, while the fish dorado is called dolphin fish. [9]In common usage the term 'whale' is used only for the larger species under cetaceans,[10] while the smaller ones with a beaked or longer nose are considered 'dolphins'. [11] The name 'dolphin' is used casually as a synonym for bottlenose dolphin, the most common and familiar species of dolphin. [12] Orcas and some closely related species belong to the delphinidae family and therefore qualify as dolphins, though they are called killer whales in common usage.
Though the terms 'dolphin' and 'porpoise' are used interchangeably, porpoises are not considered dolphins and have different physical features such as a shorter beak and spade-shaped teeth; they even differ in their behavior. Porpoises belong to the family Phocoenidae and share a common ancestry with the delphinidae under the suborder odontocetes. [12] A group of dolphins is called a school or a pod. Male dolphins are called bulls, females cows and young dolphins are called calves.
