Bottlenose dolphins are present in most oceans and seas of the world and adapt quickly to several types of habitat.

Their thermoregulation capacity allows them to live in waters ranging from 10 to 32 degrees Celsius, which includes temperate, tropical and subtropical areas of the Pacific, Atlantic, Indian Ocean, as well as the Mediterranean Sea and the Black Sea between Europe and Asia. The regions that avoid are the polar zones, but some individuals move through the north of Europe, whose waters have low temperatures.

In the Pacific, their distribution range is from northern Japan to Australia and from southern California to Chile in the eastern Pacific Ocean including all the vast area in the middle.

In the Atlantic ocean, they dwell from Nova Scotia to Patagonia in the West and from Norway to South Africa in the East including all the eastern coast of the United States, and the Gulf of Mexico.

Bottlenose dolphin habitat includes bays, open waters, coastal areas, lagoons, estuaries, tidal areas and shallow areas. They even venture occasionally into some rivers.

The other bottlenose species, the Indo-Pacific bottlenose dolphin, is also distributed in tropical and subtropical areas in specific regions of the ocean. This dolphin inhabits from western South Africa to Japan, including eastern and western Australia and places such as the Red Sea, Persian Gulf, Solomon Islands and the Indo-Malay archipelago.

The Indo-Pacific dolphin lives near the coasts of continental shelves, at depths of less than 300 meters and around oceanic islands. It frequently visits estuaries and coral reefs where fish banks thrive, and a significant amount of cephalopods live. Therefore it tolerates salt water and brackish waters.

In the vast ocean, all creatures are vulnerable. Bottlenose dolphins are cetaceans that rarely become prey, thanks to their size, their intelligence, the use of echolocation and their level of socialization that gives them a significant advantage by staying in groups and intimidating their opponent. However, two predators will take the smallest opportunities to feed on dolphins: killer whales and sharks.

We know that the killer whales are expert hunters, especially when they hunt in organized groups. Although there are few documented cases, these animals that are the world’s largest dolphins, attack other species of smaller dolphins, mainly young, newborn or sick. To do it they separate the mother from the calf, making impossible to the latter defend its offspring.

However, a group of orcas does not feel intimidated by a large pod of dolphins. Although there are no records of this kind of attack to bottlenose dolphins, there are videos where a pod of killer whales approaches aggressively to groups of dolphins of other species, and as if they were seals, they beat them and throw them into the air until they are stunned and finally feed on them. Several types of dolphins suffer this kind of aggression, and the bottlenose dolphins are likely part of this list.

Regarding sharks, the most dangerous species for members of the genus Tursiops are the largest: tiger shark, sand shark, bull shark and, of course, the great white shark. It is not uncommon to observe dolphins with scars from shark attacks, which means they are not easy prey and their escape techniques often help them survive.

A study conducted in Shark Bay, Western Australia, revealed that 95 of 128 bottlenose dolphins analyzed showed scars from shark bites, mostly from tiger sharks. The frequency of new body marks and the high attack rates suggest that bottlenose dolphins are at risk in this locality more than in other parts of the world.

A few cases with rays are known. Although they are not dolphin predators because they have a diet based on small fish, mollusks, and plankton, the trauma and infections they cause with the sharp edges of their tail sometimes become deadly.

(Tursiops aduncus)

INFORMATION AND CHARACTERISTICS.

Before 1998, the Indo-Pacific bottlenose dolphin was considered a member of the species Tursiops truncatus (Bottlenose dolphins) because of their incredible physical resemblance. After several studies, scientists realized that this species is smaller and has more teeth than Tursiops truncatus, so in 1998 the Indo-Pacific bottlenose dolphin became a separate species according to its genetic and morphological characteristics.

Further research found that this dolphin is even more related to the genus Stenella and the genus Delphinus than to the bottlenose dolphin, but there are no changes in its taxonomy yet.

Order: Cetacea
Family: Delphinidae
Genus: Tursiops

HOW DO THEY LOOK? PHYSICAL CHARACTERISTICS.

The Indo-Pacific bottlenose dolphin has a similar physical resemblance to the common bottlenose dolphin. Both species have homodont denture and conical dental pieces with a diameter of 1 centimeter. Compared to other mammals, Tursiops aduncus has more red blood cells and 29 times more myoglobin (muscle protein).

Morphology.
It has a fusiform body, a large dorsal fin, small head, and face that narrows from the base. The length of its skull is shorter compared to the bottlenose dolphin.

Size and weight.
It is a small dolphin whose average length is 2.6 meters being males slightly larger than females. Its weight oscillates around 230 kilograms.

Skin Coloration.
The dorsal part of its body has a dark gray color that extends to the sides while the ventral region is whitish. Its pectoral flippers are also dark gray.

Distinctive characteristics.
One of the features that indicate that it is an Indo-Pacific dolphin is the presence of small spots in the ventral area in adults who are sexually mature although some individuals lack them.

WHERE DO THEY LIVE? DISTRIBUTION AND HABITAT.

The Indo-Pacific dolphin has a distribution in the tropics and subtropics of the Indo-Pacific as its name suggests. It inhabits from the west of South Africa to the southern part of Japan and the north, east and west of Australia including the Red Sea, the Persian Gulf, the Solomon Islands and the Indo-Malay Archipelago.

The waters of the countries hosting these dolphins are Australia, Bangladesh, China, Cambodia, Djibouti, Eritrea, Indonesia, China, Egypt, Iran, Brunei, Iran, Kenya, Madagascar, Malaysia, Mozambique, Oman, Pakistan, Arabia South Africa, Sri Lanka, Taiwan, Tanzania, Timor-Leste, Thailand, United Arab Emirates, Philippines, Japan, Solomon Islands, New Caledonia, Vietnam, Yemen and New Guinea.

This dolphin inhabits areas near the shores within the continental shelf in waters with depths less than 300 meters and around the islands. Its habitat varies depending on the tides and the season but includes estuaries, coral reefs and surface waters at high seas, so it tolerates both saltwater and brackish water.

87 percent of their food is made up of about 50 species of fish.

WHAT DO THEY EAT? DIET AND EATING HABITS.

Tursiops aduncus feeds on bony fish as well as cephalopods. A study of its feeding habits showed a preference for about 50 species of fish and three species of squid, that is, 87 percent of their diet is composed of the former, and 13 percent corresponds to these cephalopods. They also consume a minimum amount of crustaceans.

The species that make up their favorite foods are the
– Striped threadfin (Polydactylus plebeius).
– Chub mackerel (Scomber japonicus).
– Kaup’s arrowtooth eel (Synaphobranchus kaupii).
– Yellowtail emperor (Lethrinus crocineus).
– Common Cuttlefish (Sepia Officinalis).
– Broadclub Cuttlefish (Sepia latimanus).
– Bigfin reef squid (Sepioteuthis lessoniana).

Among others.

It commonly feeds alone although sometimes cooperates with other dolphins to obtain prey. To do this, they perform several dives for short intervals. If it is in very shallow waters it can a) drag the fish down and hit them against the sand with its tail or b) chase the prey to the surface to kill it and eat it.

HOW DO THEY REPRODUCE? MATING AND REPRODUCTION.

Females reach sexual maturity a few years earlier than males. The former can start reproducing at seven years, but the latter begin up to nine years. Mating and births occur more frequently during the spring and summer months.

The males of these dolphins show a strange behavior in mammals: they build alliances by integrating groups of 2 or 3 members that allow an easier pairing with a particular female. On the other hand, single males tend to protect a pod of females.

The Indo-Pacific bottlenose dolphins are polygamous. A male knows that a female is already sexually mature when she shows spots on her skin. When they are ready, both copulate for a few seconds with the bellies united in the same direction.

The gestation period lasts about 12 months, after which a single calf is born that weighs between 9 and 21 kilograms and measures 0.8-1.1 meters in length. From the first seconds of life, the calf can swim following its mother. Calves are weaned when they are 2-8 years old, and mothers can get pregnant every four years.

HOW DO THEY BEHAVE? BEHAVIOR

Like most dolphins, it is a highly social species that groups with 5-15 peers, yet they are shyer than common bottlenose dolphins. Associations are formed according to size, age, and gender and can sometimes meet with other species of dolphins.

They are mostly diurnal and sedentary because they remain in their birth zones throughout their lives. They have a high learning ability, and it is not strange to see them playing. They have an excellent auditory capacity and emit a kind of individual whistles that identify them with the other members of the same pod or the same species.

WHAT IS THEIR CONSERVATION STATUS? THREATS AND CONSERVATION.

Conservation Status: “Data Deficient.”

Their natural predators are mainly white sharks (Carcharodon carcharias), tiger sharks (Galeocerdo cuvier), dusky sharks (Carcharhinus obscurus) and other species of shark as well as killer whales (Orcinus orca).

Since it is used to live near the coasts, it is more susceptible to the dangers of human activities and their consequences: degradation of its habitat, direct hunting, and bycatch. Industries use parts of their body to market the meat and produce oils and lubricants. Also, they are common animals in aquariums, so they are the target of the tourism businesses.

To date, there is no information on its conservation status since the International Union for Conservation of Nature includes it in the category “Data Deficient.” There are no specific conservation strategies for this dolphin.

References

http://www.conabio.gob.mx/institucion/cooperacion_internacional/TallerNDF/Links-Documentos/Casos%20de%20Estudio/Mammals/WG5%20CS2.pdf

http://www.cms.int/reports/small_cetaceans/data/t_aduncus/t_aduncus.htm

https://en.wikipedia.org/wiki/Indo-Pacific_bottlenose_dolphin

Jefferson, Webber, Pitman. Marine Mammals of the World: A Comprehensive Guide to Their Identification. Academic Press, 2015. Page 244.

]]> https://www.dolphins-world.com/map-of-where-bottlenose-dolphins-live/ Wed, 02 Oct 2013 20:43:31 +0000 http://www.dolphins-world.com/?p=416 Answer:

Bottlenose dolphins dwell in all the oceans around the globe. They can live from temperate waters to tropical waters of both the Pacific and the Atlantic Oceans.

Their limits are the cold temperatures of the Arctic and Antarctic Oceans where the water temperature is freezing.

Below there is a map that shows the vast region inhabited by Bottlenose dolphins.

This map shows the extense region of the Oceans where the bottlenose dolphins live

Bottlenose dolphins do not have a migration pattern defined which would take them from one place to another every year during the winter.

However, during winter populations of bottlenose dolphins living in North areas could look for southern temperate waters.

While bottlenose dolphins do not migrate in the summer, they move to different locations due to the change in water temperatures, which cause their common prey to move from one place to another.

In summer bottlenose dolphins do not have a particular place to go, they tend to travel and move around for food back and forth.

However, it is important to mention that dolphins travel a lot looking for food, covering sometimes more than 4,000 km in a month.

Bottlenose dolphins are one the dolphin species widely distributed around the global oceans.

They live in the temperate and tropical waters of the Pacific and Atlantic Oceans and every sea that has this kind of waters.

They are not present in the Arctic or Antarctic oceans where the water temperatures are extremely low.

There are only two species of bottlenose dolphins, the Common Bottlenose Dolphin (Tursiops truncatus) and the Indo-Pacific Bottlenose Dolphin (Tursiops aduncus).

Also, there are two recognized subspecies of Tursiops Truncatus:

The Pacific Bottlenose Dolphin (Tursiops Truncatus Gillii) which lives in the Pacific ocean.

The Black Sea Bottlenose Dolphin (Tursiops truncatus Ponticus) which lives in the Black Sea.

Bottlenose dolphins inhabit every ocean in the world, and there are populations scattered all over the sea.

Thye can be found swimming in temperate and tropical waters of all the oceans only avoiding the Arctic Ocean in the north and the Antarctic Ocean in the south, where the water temperature is freezing.

Japan, Australia, Bermuda, Madagascar, South Africa, and Thailand, are some of the countries where these dolphins live in their natural habitat.

Bottlenose dolphins are probably one of the best-known species of animals. They have a length of around 10 to 14 feet and a streamlined body with a large fin at the top. Their skin is gray and smooth without long hair like most mammals.

Some look small, and others are much larger and heavier, since their range is between 150 and 650 kilograms, with males having larger body dimensions than women, so there is sexual dimorphism.

One of the characteristics of bottlenose dolphins is their thick and notorious snout that give them their odd colloquial name.

Other features of bottlenose dolphins are the flippers and their powerful caudal fin.