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- What is the difference between dolphins, fish and sharks?
Dolphins are mammals. This means that they breathe air, give birth to live young and nurse those young. Fish however, lay eggs and breathe underwater through their gills. Sharks are a bit different. They are fish, but some give birth to live young. However, all sharks also breathe through their gills. Sharks' skeletons are made out of cartilage, not bones.
- What predators and threats do the dolphins you study face?
In the Bahamas, spotted dolphins have to be on the look out for three species of sharks. The hammerhead shark, the tiger shark and the bull shark. Their best defense against these sharks is avoidance. Contrary to popular belief, dolphins do not seek out shark interactions. If they should be threatened by sharks, however, they can defend themselves with their strong rostrums and powerful flukes. Also, sharks in this area tend to travel alone, while dolphins travel in groups-anywhere from 3-30 dolphins. The more dolphins, the more eyes, ears and echolocation to keep an "eye" out for sharks! Aside from sharks, spotted dolphins in the Bahamas have to be concerned about fast boats. Boats that are driven erratically and fast than the dolphins can swim (up to 25 mph), put the dolphins at risk for painful and sometimes fatal propeller wounds. Improperly used and discarded fishing hooks and lines can also cause grave injuries to the dolphins. An important reason to remember to keep our oceans clean!
- How many calves do they have at a time? In a lifetime?
Although there have been reports of dolphins giving birth to twins, they most often give birth to one calf at a time. When two dolphins are born together, one usually doesn't survive. They can stay with mom until she gets pregnant again, between 3-5 years. Gestation period is11-13 months.
- Do dolphins mate for life?
No, dolphins are very promiscuous. Males and females do not stay together; a calf will stay with its mother. Males are not involved in the care of calves.
- What are cetaceans?
Cetaceans is a collective term for whales, dolphins and porpoises. The name is derived from the scientific (Latin) name of these animals: Cetacea.
- What is a dolphin fish?
Dolphins are marine mammals, but there is also a fish species that's often called "dolphin" or "dolphin fish". Its scientific name is Coryphaena hippurus. To avoid confusion with the mammal species its Spanish name "dorado" or its Hawaiian name "mahi mahi" is often used. Because of the confusion between the mammal and the fish species dolphins have in the past erroneously been called porpoises, especially in some US regions, where the fish species is common. In older books you can encounter the name "bottlenose porpoise" for the bottlenose dolphin, for instance. Dolphins and porpoises are however members of different whale families. You can find more information about the dolphin fish, including its common name in other languages, in the FishBase database, online at http://www.fishbase.org/
- What is the smallest dolphin species?
There is not really one smallest species. The smallest species include: True dolphins (Delphinidae): * Tucuxi (Sotalia fluviatilis) - 1.3 to 1.8 m * Hector's dolphin (Cephalorhynchus hectori) - 1.2 to 1.5 m * Black dolphin (Cephalorhynchus eutropia) - 1.2 to 1.7 m * Commerson's dolphin (Cephalorhynchus commersonii) - 1.3 to 1.7 m River dolphins (Platanistidae): * Franciscana (Pontoporia blainvillei) - 1.3 to 1.7 m Porpoises (Phocoenidae): * Vaquita (Phocoena sinus) - 1.2 to 1.5 m * Finless porpoise (Neophocaena phocaenoides) - 1.2 to 1.9 m
- What is the largest dolphin?
The killer whale (Orcinus orca). Male killer whales can grow up to 9.6 m (31.5 ft). Spotted dolphins get to be about the size of a grown human-between 4-6 feet, up to 250 pounds. When they are born, they are much smaller-usually between 2-2.5 feet. Bottlenose dolphins grow to be between 6-8 feet.
- How many species of dolphins are there?
The taxonomy of whales and dolphins is still subject to change. But in the most common view, the family of dolphins (Delphinidae) consists of 32 different species. Closely related families (the white whales (Monodontidae) and river dolphins (Platanistidae) have 2 resp. 5 species).
- Do dolphins drink water?
Most dolphins live in the ocean and the ocean water is too salty for them to drink. If they would drink sea water, they would actually use more water trying to get rid of the salt than they drank in the first place. Most of their water they get from their food (fish and squid). Also, when they metabolize (burn) their fat, water is released in the process. Their kidneys are also adapted to retaining as much water as possible. Although they live in water, they have live as desert animals, since they have no direct source of drinkable water.
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