Brief Overview: Dolphins are part of the Delphinidae family and river dolphins are part of the Platanistidae family. The name “dolphin” comes from the Ancient Greek word “delphis” that means “fish with a womb”. Dolphins are believed to be one of the most intelligent creatures in the world compared to other animals. There are two types of dolphin, freshwater dolphins, and ocean dolphins.
Species and Appearance: There are currently 36 different species of ocean dolphins and five species of river dolphins. The orca, or killer, whale is actually not a whale at all. It is in fact, a type of dolphin. The most common species is the bottlenose dolphin and is the most well-known. They can grow up to 12 feet long and swim up to 22 miles per hour. The dolphin has been known to jump up to 16 feet high from the water and always lands on its side or back. A dolphin has a thick layer of fat beneath its skin called blubber which can be found in every water-based mammal like whales and seals. This blubber helps the dolphin stay warm when swimming in colder waters. Dolphins vary in colour and sometimes a mix colour of black, gray, and white and have smooth rubbery skin. Like fish they have fins on their sides and a fin on top of their backs.
Habitats and Locations: Dolphins have no specific location and their habitat is always within the water. Dolphins travel all throughout the world across every ocean and past every continent. While a majority live in saltwater, there are some that can only live in freshwater.
Survival and Behavior: Female dolphins have been known to be called “cows”, while the males would be called “bulls”. Baby dolphins are known as “calves”. Dolphins are highly social animals, preferring to live in groups known as “schools”, or “pods” with their average size between 12 – 20. However, it is to be noted that sometimes various pods do get together to form super pods which can range from 100 – 1000. As mentioned before, dolphins are very social animals and are especially playful with each other and humans which makes them one of the most popular animals. They can be seen jumping out of water to perform tricks, ride waves, play fight, and would even, occasionally, interact humans swimming. Dolphins have been known to have excellent eyesight and hearing, but they are famous for using a special sonar called, “echolocation”. This is a technique that bounces sound and vibrations through the water off objects and allows them to find the location of food, predators, or other dolphins. When hunting they communicate with each other through clicking and whistling sounds. Being intelligent as they are, the dolphins have even developed a technique is called “sheep-herding” which allows them to hunt more effectively. A group of dolphins circle a large group of fish to prevent them from escaping while other dolphins take turns eating them. They can also dig a crater in the sandy grounds underwater to pull out hidden fish using their sonar pulses. Dolphins sleep at night only for a couple hours at a time before hunting for food and can swim down to 838 feet for up to 15 minutes before needing to resurface.
Diet and Predators: Dolphins are carnivores and eat a variety of fish. The type of fish they eat mostly depends on the fish they hunt like herring, cod, mackerel, and sometimes the squid can range as well. Their natural predators are actually few in variety but large in diversity with the main source of danger coming from sharks. However, killer whales have been known to attack other dolphins for food as well.
Breeding and Lifespan: Dolphin’s mating season can happen at any time of the year, but for some species it happens specifically in the spring and autumn seasons. Dolphins are known to have more than one mate at a time. Depending on the type of dolphin, the pregnancy can last under a year while others can go over a year between 14-18 months. Female dolphins will distance themselves from their group and go near the surface of the water to give birth. Dolphins give birth to only one calf at a time every year and this cycle ranges from one to six years. With dolphins being mammals, they nurse their babies with milk for two 11 months to two years. When a calf is born the mother will take it to the surface so the animal can breathe its first breath. The mother will teach their calf everything they know. The calves would normally stay with their mothers for around three to eight years before they go off on their own. A dolphin can live up to 20 years in captivity. Ironically, in the wild each dolphin has their own limited lifespan but are higher than in captivity with females outliving the males. A killer whale can live up to 90 years, while a dolphin can reach up to 55-60 years old.