Did you know that dolphins are marine mammals?
Because dolphins are mammals, they are warm-blooded, breathe air, give birth to their offspring, and nurse their young with milk.
Unlike fish that have gills and can breathe underwater, dolphins require air to breathe and must come to the water’s surface when they need oxygen.
These fantastic marine animals belong to the cetacean family, including two marine mammals known as whales and porpoises.
When you combine all three types of marine mammals, there are over 85 different cetaceans species.
When it comes to the dolphin species, there are currently around 40 species of dolphin that live in the ocean today.
Dolphins are smart and playful animals.
They are also one of the most acrobatic species known to inhibit the sea.
Dolphins can dive up to 1000 feet underwater, jump over 25 feet high, and swim faster than 30 miles per hour.
Depending on dolphin species and their location, their diets can vary significantly.
Some of the foods dolphins eat include herring, cod, squid, plankton, crustaceans, fish, and even other marine mammals such as whales!
Most species restrict their diet to small fish, squid, and crustaceans, but a couple of species, such as the killer whale and false killer whale, have been known to attack large prey and marine mammals.
The killer whale and false killer whales are part of the dolphin species, not the whale species.
Physical Characteristics
In terms of size, dolphins vary greatly, from Maui’s dolphin, which measures around 4 feet and weighs about 90 – 110 pounds, to the killer whale, which can grow to 30 or more and weigh as much as 22 000 pounds.
Most dolphin species have slim, streamlined bodies created to give them great speed and agility, and a few species have rounder and more stocky bodies.
To swim and pick up speed, dolphins use their tail for propulsion and their fins for stabilization which helps them turn, roll and navigate through the water.
Unlike some whale species with two blowholes, dolphins are born with a single blowhole.
Also, unlike some whale species, most dolphins make short migration trips or stick to a single area all year long rather than extensive journeys to new destinations.
Habitat and Migration
When dolphins migrate, they usually follow their food source, which is vital for survival.
Dolphins typically prefer tropical climates.
However, some species, such as killer whales, may live in colder climates.
Most species belong to one of two ecosystems.
Coastal dolphins prefer to stay near the coast in shallow waters, where most dolphins appear.
Offshore dolphins are typically larger than coastal dolphins and prefer to live further out in the ocean.
Because coastal dolphins live in and around the coastline, they are often limited in their range of travel.
Hence, they stay in or near the safer coastal waters, where they are less likely to be threatened by larger marine mammals and other threats found in the ocean.
On the downside, these dolphins are also more likely to suffer from water pollution and fishing hazards, such as being caught in fishing nets and struck by large boats.
Offshore dolphins are more prominent and do not live near the coastline.
Instead, they are more likely to migrate during seasonal changes and when their food supply migrates.
Social Structure
Dolphins are intelligent and social creatures, often traveling in groups of 2 – 30.
In some cases, such as during feeding periods or social activities, dolphin groups may be much larger, containing several hundred dolphins at a time.
Besides gathering together for social events, dolphins also form large pods or groups to protect themselves against predators.
Dolphins communicate with one another by creating a series of clicking and whistling sounds.
They also use various body language signs, such as leaping out of the water, slapping their fins against it, and bumping into one another.
These sounds and signs allow dolphins to communicate affection, alert other dolphins of nearby danger, and inform others of food they have found, among other things.
Interestingly each dolphin has a slightly different frequency when it communicates.
It allows other dolphins to distinguish which one in the groups is communicating.
These sounds can also help a dolphin find other dolphins that belong to its pod or help a mother keep track of her children.
In addition to communicating with one another through sound, dolphins use echolocation to help them track prey and navigate the ocean, which is especially useful when visibility is low at night or during deep dives.
Pregnancy Cycle
When it comes to giving birth, the average gestation period for a female dolphin is 11 – 17 months, depending on the species.
Female dolphins typically produce offspring every 2 – 6 years and raise their young for several years after birth.
Female dolphins usually mature between the ages of 5 – 13, while males usually mature between 6 – 14.
However, some dolphin species may mature at later ages.
Unlike certain whale species with feeding and mating seasons, dolphins can bear offspring all year long.
However, dolphins are more likely to mate during the warmer months.
During mating, adult male dolphins can become aggressive and competitive, sometimes fighting with other males or herding off the female to limit their chances of becoming impregnated by other males.
Some male dolphins will even create factions fighting and fending off other factions trying to mate with their females.
10 Awesome dolphin facts for kids
- The largest known dolphin is the killer whale (yes, the killer whale is a dolphin), which can grow to lengths of over 30 ft. long.
- All species of dolphins can use echolocation to hunt for food and navigate the ocean in completely dark environments.
- Sound travels four times faster in water than on land, and dolphins have an excellent sense of hearing, allowing them to maintain awareness of their environment and react quickly when necessary.
- Although dolphins have teeth, not all species use their teeth when hunting for food, and some dolphins swallow their prey whole.
- Depending on the species, some dolphins can be found traveling in the world’s major oceans, from the tropical environments near the equator to the polar regions around the northern and southern polar hemispheres.
- Some dolphins are known to hold their breath for over 15 minutes when searching for food.
- The fastest dolphins can reach over 30 miles per hour for short bursts when frightened or trying to capture prey.
- The personalities of dolphins can vary just as much as humans. Although dolphins are known for being extremely social and acrobatic, several species are more reserved and prefer to remain distant and undetected.
- Dolphins are so intelligent that some species have been used in the military to find underwater mines and look for passengers lost at sea.
- Some dolphins have unfused necks allowing them to turn their head a full 90 degrees to maintain constant awareness of their environment.