The life cycle of dolphins is similar to that of land mammals.
Some species of dolphin 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 bare offspring regardless of the time of year and may mate for pleasure.
Prior to mating, the male dolphin might court the female dolphin by swimming with her or they may pet each other with their fins.
The mating process itself isn’t very long and typically occurs during the spring months.
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 but speculate that these actions are intended to indicate the male dolphin’s fitness or to 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.
During birth, the adult females of the pod may surround the pregnant dolphin 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 is able to swim and breathe on its own 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 retain the ability to produce milk after their period of fertility even if they have not produced offspring.
The mother nurses the calf for 6 months to 2 years depending on the species and their psychological dependency on their mother.
Additionally, calves are also able to eat crustaceans and fish beginning around the age of six months.
After the calf is weaned, it remains with its mother for an additional three to eight years until it reaches puberty.
During this time the mother protects and cares for her calf and may be assisted by other female members of the pod.
It takes between five and ten years for a calf to reach puberty and mate among most dolphin species.
Dolphins travel in pods of up to 40 dolphins and are known to 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.
Occasionally several pods, sometimes consisting of different species of dolphins, will group together into a school or herd that can consist of up to several hundred members.
Living in pods allows dolphins to form a community in which they are better able to hunt prey, defend themselves, and care for their young.
Dolphins are carnivores and are known to eat fish or cephalopods, including squid, octopus, and cuttlefish.
Some species of dolphins have a more varied diet, feeding on crabs, shrimps, and lobsters as well as on 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.
In order to attaining 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 are also able to attain higher than average speeds by riding the bow wave of a fast-moving boat or ship.
Dolphins also possess keen skills of echolocation 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 known to be extremely intelligent and trained dolphins are able to imitate human behavior during play.
The average life expectancy of a dolphin is 30 years, however their lifespan can vary from 20 – 50 years depending on the species and their situation.
Death can occur as a result of old age; diseases or parasites; bacterial, fungal, and viral infections; heart disease; respiratory disorders; skin diseases; stomach ulcers; tumors; or urogenital disorders.
When it comes to the life cycle of dolphins in captivity there are huge differences in terms of health (both social and physical), mortality rates and lifespan.
In fact dolphins that live in captivity may have a lifespan that is 1/2 – 1/3 that of dolphins that live in the wild.
This can occur for several reasons.
First, dolphins are very social and require healthy relationships in order to thrive and survive.
Dolphins that are held in captivity for too long and those that are born into captivity often lack these important relationships which can deeply 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 very long distances with some dolphins swimming as much as 100 miles in a day.
They may also dive 100’s of meters below the waters surface to hunt for food or during other types of activities.
In contrast dolphins held in captivity have very little space to move around in and are often in very shallow waters.
While we cannot be 100 percent sure the different properties of the ocean and the water that dolphins are held in when in captivity may also play a huge role in their health and survival rates.
As stated earlier the morality rates of those born into captivity is 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 own mothers.
Debates regarding captivity
The growing debate over whether or not dolphins should be held in captivity is likely to continue for many years.
There are certain cases where captivity can serve as a place for dolphins to recover and recuperate after a serious injury where they likely wouldn’t survive in the wild or under circumstances where they need to be protected from harmful factors in their natural environment, however this type of captivity is likely best used as a last resort and as a temporary fix rather than a permanent solution.
Once the dolphin or group of dolphins have 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.