The rough-toothed dolphin (Steno bredanensis ) is a species of dolphin that can be found in deep warm and tropical waters around the world.
The species was first described by Georges Cuvier in 1823. The genus name Steno, of which this species is the only member, comes from the Greek for 'narrow', referring to the animal's beak — which is a diagnostic characteristic of the species. The specific name honours van Breda, who studied Cuvier's writings. There are no recognised subspecies.
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DiurnalDiurnal animals are active during the daytime, with a period of sleeping or other inactivity at night. The timing of activity by an animal depends ...
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NocturnalNocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal",...
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CarnivoreA carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of a...
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MolluscivoreA molluscivore is a carnivorous animal that specializes in feeding on molluscs such as gastropods, bivalves, brachiopods, and cephalopods. Known mo...
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PiscivoresA piscivore is a carnivorous animal that eats primarily fish. Piscivorous is equivalent to the Greek-derived word ichthyophagous. Fish were the die...
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AquaticAn aquatic animal is an animal, either vertebrate or invertebrate, which lives in water for most or all of its life. It may breathe air or extract ...
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PrecocialPrecocial species are those in which the young are relatively mature and mobile from the moment of birth or hatching. Precocial species are normall...
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NatatorialNatatorial animals are those adapted for swimming. Some fish use their pectoral fins as the primary means of locomotion, sometimes termed labriform...
Among animals, viviparity is the development of the embryo inside the body of the parent. The term 'viviparity' and its adjective form 'viviparous'...
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starts withThe Rough-toothed dolphin’s curious name and difference to other dolphin species refers to its very prehistoric reptile look, having wrinkles and ridges on their teeth. The four sections of the teeth in their upper and lower jaw have between 19 and 28 teeth. Their narrow beak is noticeable, and they have a small head. They are small dolphins, and they do not have a crease in their melon like other dolphins.
Rough-toothed dolphins are found in all of the world’s three major oceans: the Pacific, Atlantic and Indian. In the US there are two recognized populations: in Hawaii and the northern Gulf of Mexico. They inhabit warm temperate and tropical waters, usually over 25 degrees Celsius, and typically occur in deep, offshore waters.
Rough-toothed dolphins are diurnal creatures, most commonly found in groups of 10 to 30, though pods of as many as 160 individuals have been seen, containing eight smaller groups. Sometimes they are seen with Pilot whales, Spotted dolphins, Bottlenose dolphins, and Spinner dolphins. These animals are great divers, staying submerged for up to 15 min. They are fast swimmers, often swimming just below the surface of the water, their dorsal fins being clearly visible. This species enjoys "surfing" or bow-riding, though not as often as other tropical dolphins. Their most commonly observed behaviors are travelling, physical social contact with pod members, resting, feeding, object play, milling and sexual activity. They communicate with each other with echolocation clicks, burst pulse signals, whistles, and synchronous swimming patterns.
Rough-toothed dolphins are carnivores (piscivores and molluscivores) and their diet includes silverside, saury, needlefish, squid and mahimahi, their preference being for the latter.
Little is known about the mating systems of these dolphins in the wild, including whether there is a certain season for mating. The gestation period is about 100 days. A single calf is born, tail first, every 1-4 years. Calves drink their mother’s milk and gain weight fast. Their mother introduces them to fish when they are about 2 months old. Females are sexually mature at 9 to 10 years old, when they measure 212 to 217 cm. Males are sexually mature at 5 to 10 years old when they are about 216 cm long.
The main threat to this species is likely to be as bycatch in fishing nets. It is also hunted for its meat in several countries including Japan, Indonesia, Sri Lanka, Papua New Guinea and the Solomon Islands. Habitat destruction as a result of human disturbances is another threat to this species.
The species is widespread and abundant, and it's current population estimates around 150,000. According to the IUCN Red List resource, an estimated 145,900 Rough-toothed dolphins live in the eastern tropical Pacific, and around 2,746 occur in the northern Gulf of Mexico, with an estimated 1,238 on the continental shelf. The regional population around Hawaii has been estimated by the US NMFS at 19,904 individuals. Overall, Rough-toothed dolphins are classified as Least Concern (LC) on the IUCN Red List.
Rough-toothed dolphins help control adult populations of mahimahi, as it's their preferred food.
Social animals are those animals that interact highly with other animals, usually of their own species (conspecifics), to the point of having a rec...