The genus S. attenuata (pantropical spotted dolphin), S. longirostris (spinner dolphin), S. coeruleoalaba (striped dolphin), S. frontalis (Atlantic spotted dolphin), and S. clymene (Clymene dolphin).(do et al., 2015). They are more commonly known as the spotted, striped, and spinner dolphins. dolphins are a part of the family Delphinidae which consists of dolphins, killer, whales, pilot whales, and their relatives. Dolphins are part of the suborder Odontoceti better known as the toothed whales. They are also part of the bigger order Cetacea which is comprised of all marine mammals.consists of 5 species of dolphins:
The genus (Editors of Encyclopaedia Britannica, 2021)can be found in tropical, subtropical, and temperate waters (do et al., 2015, Moreno et al., 2005). They can be seen surfacing, and have been found as far down as 5,000m. All the species can be found in groups-known as pods-of sizes of 1 individual to hundreds of individuals. They can grow up to lengths of 195 cm-235 cm (76in-92in), and will weigh on average 72 kg-80kg (158lbs-176lbs). They will typically have varying beak lengths as well. These species are typically carnivorous and will feed on a variety of small organisms from the pelagic and benthopelagic waters, such as lanternfish, squid, shrimp, and fishes.
These 5 species of dolphins are found in the Pacific, Atlantic, and Indian oceans. None are found in the polar regions of the oceans. Of the 5 species of dolphins in genus S. clymene and S. frontalis are endemic to the Atlantic ocean, Gulf of Mexico, and Caribbean (do et al.,2015, Moreno et al., 2005). The other 3 species: S. Attenuata, S. longirostris, and S. coreruleoalba are found throughout all 3 of the mentioned oceans. They are commonly found in warmer regions of the oceans. (Bohrer do Amaral, et al., 2015; Moreno, et al., 2005), 2 of the species:
These species live in tropical, subtropical, and temperate waters; mostly in the deeper open ocean waters, but some species will move to shallower waters closer to shore. They typically will be found in the water column in a range from 20m-200m in shallower waters, and 700m-5,000m in the deeper waters. They are found in waters with temperatures that range typically 18°C-22°C (64°F-72°F), but can be anywhere from 10°C-22°C (50°F-72°F). (Editors of Encyclopaedia Britannica, 2021)
These dolphins are part of the greater superorder "Cetartiodactyla" which split into the two major orders: "Artiodactyla" which consists of the ruminants, peccaries, pigs, hippos, llamas, and camels; and "Cetacea" which consists of porpoises, whales, and dolphins. It is estimated that order "Cetacea" diverged from the Artiodactylates in the early Eocene period, about 60 Mya (Theordor, 2016). After their divergence from "Artiodactyla" the Cetaceans split into two main suborders the "Odontocetes"-the toothed whales and "Mysticetes"-the baleen whales around 33.8 Mya in the mid to late Eocene period (Marx and Fordyce, 2015). Furthermore, within suborder "Odontocetes" all dolphins are grouped under family "Delphinidae" which was estimated to first have appeared during the early Miocene period, about 23-16 Mya (Encyclopedia Britannica, 2021).
In 1866, John Gray used the name "Steno". " " has now since been defined as its own genus in the family "Delphinidae". The genus " " groups together the 5 species of dolphins- "S. attenuata", "S. clymene", "S. coeruleoalba", "S. frontalis", and "S. longirostris". The species "S. attenuata" is split into two subspecies: "S. a. attenuata" and "S. attenuata graffmani", and the species "S. longirostris" is split into three subspecies: "S. l. longirostris", "S. longirostris centroamericana", and "S. longirostris orientalis". In the late 1800s other names were used to define this group, but are no longer used today and some of the names are still used to define a few specific species within this genus. (Editors of Encyclopaedia Britannica, 2021; Hassanin, et al., 2012; Marx and Fordyce, 2015; Ralls and Mesnick, 2019; Theodor, 2004)" to define several species of dolphins as a subgenus of the genus "
Dolphins are social animals. They can live in pods as small as a few individuals and as large as hundreds of individuals. They can be found living solitary lifestyle, but are most often found in pods. These social groups usually consist of a larger number of females than the number of males; typically with a ratio around 60% females to 40% males(Perrin et. al.,1976). In these pods there will be foraging individuals that hint for prey, and other individuals that care for the young. It takes several years for species of (Malinowski, 2015; Perrin, et al., 1976; Silva-Jr, et al., 2005)dolphins to reach sexual maturity. In females sexual maturity is reached between 7-10 years of age, and for males it is reached between 7-12 years of age. Once they are reproductively mature they are polygamous, meaning they will have multiple different mates over the course of they're lifetime. As individuals get older they're reproduction rate decreases.
When dolphins want to mate they will engage in playful activities with each other such as chasing each other, and will begin making lots of noises such as whistles, clicks, and burst-pulse signals(Silva Jr. et. al.,2005). The males will begin to gently tap their fins to the females fins and belly, and then rub, nudge, and gently bite the female. To impregnate the female the male will move below the female with his belly up, so that the two are belly to belly; the act of reproducing is quick, and will only last a few seconds to a few minutes. There are two primary seasons for mating and calving(birth)- the spring and the fall. However these reproductive peaks can vary from year to year, and high reproductive peaks can occur during the summer as well. Reproduction occurs in 3 stages: calving, lactation, and a period of inactivity or estrus(Perrin et al.,1976). (Malinowski, 2015; Perrin, et al., 1976; Silva-Jr, et al., 2005)
A female will be in the gestation(pregnancy) period for 11 months-1 year, and then will give birth to live young in the spring or fall. After giving birth females will lactate for typically 9 months, but calves can wean from lactation anywhere from 6 months to 19 months. It takes calves about 1-3 years to reach the juvenile stage and full growth. While calves are nursing they tend to stay close to their mothers. Females can be pregnant and lactating at the same time, and will give birth to only 1 calf per pregnancy. (Malinowski, 2015; Perrin, et al., 1976; Silva-Jr, et al., 2005)
S. clymene has a lifespan of around 25 years, S. attenuata has a span of 40 years(National Geographic 2022), S. coerulalba has a lifespan of up to 58 years(NOAA Fisheries, 2022), S. frontalis has a span of greater than 50 years(NOAA Fisheries, 2022), and S. longirostris has a span of 20-25 years(NOAA Fisheries, 2022). In captivity these species of dolphins have roughly the same lifespan but can live a few years longer. ("Atlantic Spotted Dolphin", 2022; Barlow and Boveng, 1991; "Clymene Dolphin", 2022; Guarino, et al., 2021; "Pantropical Spotted Dolphin", 2022; Perrin, et al., 1987; "Spinner Dolphin", 2022; "Striped Dolphin", 2022)dolphins have a lifespan of anywhere from 20 years to upwards of more then 50 years in the wild. The species
S. coeruleoalba tend to be less social and interact with other organisms less frequently than the other 4 species of dolphins. During the day they will stay near the surface and come up to the surface to breathe, and at night they dive down to feed. They will swim in zig zag or back and forth patterns moving between shallow and deeper waters, as well as engage in periods of rest. During these rest periods the pods will swim close to one another in a slow back and forth swaying as one group movement. The act of rest is typically engaged in multiple times a day for around 3-5 hours at a time(NOAA Fisheries, 2022). These dolphins are very playful, and both calves and adults will engage in playtime with each other. play consists of jumping out of the water and flipping or spinning, as well as "roto-tailing"-jumping high above the water and rotating their tail. S. coeruleoalba most often "roto-tail" compared to its sister species. The dolphins will also use spinning to communicate with each other, or to remove ectoparasites from their bodies(NOAA Fisheries, 2022). Play also consists of blowing bubbles or shooting water from the blowholes, mock chasing schools of fishes, and playing with pieces of seaweed. A dolphin will pick up a piece of seaweed and place it on its flipper, and then toss it back and forth between their flippers, beak or tails. Most often a single dolphin will play with the seaweed but sometimes two or three dolphins will all pass a singular piece of seaweed back and forth between each other. More commonly a single piece of seaweed will be shared between individuals who each in turn play with the seaweed. Also they will frequently swim up to boats and swim in the bow waves or surf the wake of these boats (Jefferson, 2003; NOAA Fisheries, 2022). ("Atlantic Spotted Dolphin", 2022; Caldwell and Caldwell, 1965; "Clymene Dolphin", 2022; Jefferson and Curry, 2003; "Pantropical Spotted Dolphin", 2022; Silva-Jr, et al., 2005; "Spinner Dolphin", 2022)dolphins will live in pods of individuals consisting of both males and females, and within these pods the individuals are organized by sex, age, and breeding status. They are an extremely social species, and will interact with other Cetaceans (whales and dolphins), as well as other marine animals, and sometimes interact with humans.
These species of dolphins will communicate using a wide range of auditory cues and sounds, as well as using some visual cues, and frequent use of echolocation. Their main source of communication is auditory sounds and acoustic signaling. These acoustic signals will be in patterns that will rise and fall in a synchronous manner. They frequently make a variety of sounds including whistles, clicks, click trains (repetitions of multiple clicks), squeaks, squeals, squawks, barks, chirps, and more. They use acoustic signaling for mating, hunting and prey spotting, as well as predator avoidance. Dolphins also use echolocation for perception of their environment. Echolocation is used to scan the environment, find prey, avoid predators, find other dolphins, and detect objects from a distance. They perform echolocation by sending out a series of clicks and the created sound waves travel until bouncing off an object and then come back to the dolphin. They use the sound waves to determine how far away an object is. This helps them locate where predators, prey, other dolphins, boats, and other objects may be. (Caldwell and Caldwell, 1965; Jefferson and Curry, 2003; Silva-Jr, et al., 2005)
These dolphins will feed mostly at night on prey from the mesopelagic (200m-1000m) waters that vertically migrate to the surface at night. The pods of dolphins will engage in cooperative hunting for their prey. They are able to catch their prey by surrounding them, and then taking turns swimming at and grabbing the surrounded prey. Their diet consists of a wide variety of small fishes, mollusks, crustaceans, cephalopods, and other small invertebrates. Typical prey for the dolphins are octopuses, and squids, shrimp, lantern fish, conger eels, flounder, jacks, and needlefish. These dolphins will have preference for some prey over others, but tend to feed on any potential prey they might come across. ("Atlantic Spotted Dolphin", 2022; "Clymene Dolphin", 2022; Jefferson and Curry, 2003; Malinowski, 2015; "Pantropical Spotted Dolphin", 2022; "Spinner Dolphin", 2022; "Striped Dolphin", 2022)
Phyllobothrium, Halocercus, Monorygma, Nasitrema, Pharurus, and various parasitic worms. Some sea birds will follow the dolphins and will eat the fish and small organisms that have been brought up to the surface and uneaten by the dolphins. They will also form commensal relationships with some species of fish and will play with them and mock chase rather than preying upon them. dolphins fill a variety of marine ecological niches. (Bohrer do Amaral, et al., 2015; Jefferson and Curry, 2003; Perrin, et al., 1987)dolphins among most other cetaceans (whales, dolphins, porpoises) fulfill the predatory ecological niches and are considered secondary, and tertiary consumers in aquatic trophic levels. Each species fulfills different ecological niches based on the water temperature and depth they spend the most time in, and as well as based on factors affecting the distribution and abundance of their prey (Amaral et. al., 2015). These dolphins will engage in habitat partitioning because of differences in environmental and ecological requirements and spatial separation between the coexisting sympatric species(Amaral et. al., 2015). These dolphins will also be host to a variety of ectoparasites such as barnacles, whale lice, and flukes; as well as host to various internal parasites such as
There are no known adverse effects ofdolphins on humans.
Abigail Ross (author), Colorado State University, Audrey Bowman (editor), Colorado State University.
the body of water between Africa, Europe, the southern ocean (above 60 degrees south latitude), and the western hemisphere. It is the second largest ocean in the world after the Pacific Ocean.
body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.
uses sound to communicate
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
an animal that mainly eats meat
uses smells or other chemicals to communicate
to jointly display, usually with sounds, at the same time as two or more other individuals of the same or different species
helpers provide assistance in raising young that are not their own
ranking system or pecking order among members of a long-term social group, where dominance status affects access to resources or mates
The process by which an animal locates itself with respect to other animals and objects by emitting sound waves and sensing the pattern of the reflected sound waves.
humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
parental care is carried out by females
A substance that provides both nutrients and energy to a living thing.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
eats mollusks, members of Phylum Mollusca
having the capacity to move from one place to another.
specialized for swimming
the area in which the animal is naturally found, the region in which it is endemic.
generally wanders from place to place, usually within a well-defined range.
An aquatic biome consisting of the open ocean, far from land, does not include sea bottom (benthic zone).
an animal that mainly eats fish
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
mainly lives in oceans, seas, or other bodies of salt water.
breeding is confined to a particular season
reproduction that includes combining the genetic contribution of two individuals, a male and a female
associates with others of its species; forms social groups.
uses touch to communicate
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
movements of a hard surface that are produced by animals as signals to others
uses sight to communicate
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
young are relatively well-developed when born
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