The life cycle of dolphins is similar to that of land mammals.
Some dolphin species appear to be only fertile for a short period every few years and typically produce offspring every 1 1/2 – 3 years.
Other species are known to bear offspring regardless of the time of year and may mate for pleasure.
Before mating, the male dolphin might court the female dolphin by swimming with her or petting each other with their fins.
The mating process isn’t very long and typically occurs during spring.
After mating, male dolphins are known to swim in elaborate patterns and make calls through their blowholes.
Researchers do not know the reason behind this behavior.
Still, they speculate that these actions indicate the male dolphin’s fitness or inform other male dolphins that he has mated with a particular female dolphin.
The gestation period of a dolphin lasts between 10 and 17 months.
The pod’s adult females may surround the pregnant dolphin during birth to protect the mother and calf.
The infant dolphin is usually delivered tail first to ensure that it has enough time to get to the surface to breathe; either the mother or another female in the pod will push the calf to the surface of the water as soon as it is birthed.
Within a few minutes of its birth, the calf can swim and breathe independently and begins to follow its mother closely.
Baby dolphins are called calves and may appear paler in color than adult dolphins.
Like all mammals, dolphins produce milk for their offspring.
Dolphin milk is rich in calcium, phosphorus, fats, and protein.
Female dolphins can produce milk after their fertility, even if they have not produced offspring.
The mother nurses the calf for six months to 2 years, depending on the species and their psychological dependency on their mother.
Additionally, calves can also eat crustaceans and fish, beginning around the age of six months.
After the calf is weaned, it remains with its mother for three to eight years until it reaches puberty.
During this time, the mother protects and cares for her calf and may assist other female members of the pod.
It takes five to ten years for a calf to reach puberty and mate among most dolphin species.
Dolphins travel in pods of up to 40 dolphins and form groups within these pods.
Groups might include a nuclear unit consisting of one male and one female dolphin, a group of young males without mates, and a nursery group containing adult females and calves.
Several pods, sometimes consisting of different species of dolphins, will group into a school or herd of up to several hundred members.
Living in pods allows dolphins to form a community where they can better hunt prey, defend themselves, and care for their young.
Dolphins are carnivores known to eat fish or cephalopods, including squid, octopus, and cuttlefish.
Some dolphins have a more varied diet, feeding on crabs, shrimps, lobsters, fish, and cephalopods.
Dolphins usually swim at a rate of 5 to 15 miles per hour but have been known to achieve bursts of speed of 25 miles per hour.
To attain higher speeds of travel, dolphins have been known to engage in what researchers call “running,” an activity in which they repeatedly dive under the water and then leap above it.
They can also attain higher-than-average speeds by riding the bow wave of a fast-moving boat or ship.
Dolphins also possess keen echolocation skills and, by emitting a series of clicking sounds through their blowholes, can determine the size, shape, direction of movement, and distance of an object or animal.
This allows them to hunt prey over long distances.
Dolphins are extremely intelligent, and trained dolphins can imitate human behavior during play.
The average life expectancy of a dolphin is 30 years. However, their lifespan can vary from 20 to 50 years, depending on the species and situation.
Death can occur due to old age; diseases or parasites; bacterial, fungal, and viral infections; heart disease; respiratory disorders; skin diseases, stomach ulcers, tumors, or urogenital disorders.
Captivity
Regarding dolphins’ life cycle in captivity, there are considerable differences in health (both social and physical), mortality rates, and lifespan.
Dolphins that live in captivity may have a lifespan of 1/2 – 1/3 of dolphins that live in the wild.
This can occur for several reasons.
First, dolphins are very social and require healthy relationships to thrive and survive.
Dolphins in captivity for too long or born into captivity lack these critical relationships, which can profoundly affect their mood and ability to lead a healthy existence.
Second, dolphins require lots of space and freedom to express themselves and live.
Dolphins that live in the wild can swim long distances, with some dolphins swimming as much as 100 miles daily.
They may also dive 100 meters below the water’s surface to hunt for food or during other activities.
In contrast, dolphins in captivity have very little space to move around in and often in very shallow waters.
While we cannot be 100 percent sure, the ocean’s different properties and the water in which dolphins are held in captivity may also play a huge role in their health and survival rates.
As stated earlier, the mortality rates of those born into captivity are often much higher than those in the wild as dolphins are born into an unnatural environment and, in numerous cases, nursed by humans rather than their mothers.
Debates Regarding Captivity
The debate over whether dolphins should be held captive will continue for many years.
In some instances, captivity can serve as a place for dolphins to recover and recuperate after a severe injury where they wouldn’t survive in the wild or under circumstances where they need to be protected from harmful environmental factors.
However, this captivity is likely best used as a last resort and temporary fix rather than a permanent solution.
Once the dolphin or group of dolphins has recovered, it may be best to let them return to their natural environment.
The longer these marine mammals stay in captivity, the better their odds of dying may be.