The average lifespan of dolphins is 25 to 35 years. However, the lifespan of a dolphin varies depending on the species. For example, the orcas can live for more than 90 years. The lifespan of bottlenose dolphins is about 30 to 50 years. The lifespan of the dolphins living in captivity can vary depending on their health and living conditions.
How to find out the age of a dolphin?
It is not as easy to find out the dolphin’s age as you may think it is. In captivity, it is easy for the observers to guess the age of the dolphins as, in most cases, they have been observing these marine animals since they were newborn babies.
There are some characteristic features of the dolphins that can give the observer an estimate of their age.
For example, you can check the cross-section of the dolphin’s tooth to find out how old the animal is. Dolphins come with only a single set of teeth, growing a little bit each year. So just like the growth ring you can observe in the trees, you can also see similar kinds of annual layers in the cross-section of dolphins teeth.
So, if you can check the number of layers present in the cross-section of the dolphin teeth, it will be easier for you to estimate the dolphin’s age.
Even though the average lifespan of the bottlenose dolphins is about 30 years in the wild, they can live for a long time. There is evidence of individual bottlenose dolphins living in the wild more than 60 years old.
It is also observed that female dolphins tend to live a longer life in the wild than their male counterparts.
Why do captive dolphins live longer?
Advancement in medical and husbandry science has significantly helped us improve the longer lifespan of dolphins living in captivity. This knowledge has helped us so much that, right now, the lifespan of bottlenose dolphins living in captivity is far better than the ones living in the wild population.
Although to live a longer life in captivity doesn’t necessarily outweigh their freedom compared to the wild dolphins. They are free to roam in their natural habitat in the wild, which is a much better experience for the dolphins, making them much happier and content.
Compared to the dolphins living in captivity, the wild population experiences a higher mortality rate in the first two years of their life. This is when the baby dolphins are most susceptible to predator diseases and adverse effects of climate change.
For the dolphins, the ocean can be a dangerous place to live. Even though the dolphins eat a similar type of seafood to humans, they often suffer from more health risks due to toxic algae in the seawater and the tainted water supplies. Like humans, dolphins can also suffer from health problems like diabetes, which is considered one of the biggest health threats that the dolphins living in the wild face.
Like any other animals, dolphins also suffer from several diseases and parasite infestation, which can lead to their death. For example, dolphins can suffer from various bacterial, viral, and fungal infections.
They can also develop skin disease, stomach ulcers, heart problems, tumours, urogenital disorders, and respiratory troubles. The parasites that generally impact the health of dolphins living in the wild are fluke tapeworms and roundworms.
Between 1987 and 1988, more than 740 dead bottlenose dolphins washed up on the sea beaches of the United States. Experts assumed that all these deaths of bottlenose dolphins were caused by morbillivirus.
Another virus that affects dolphins is the red tide toxin, created by a tiny marine organism known as dinoflagellates. It is one of the deadly viruses that can rapidly affect several different animals living in the same area simultaneously.
- Parasite infestation
- Bacterial, viral, and fungal infections
Even though the sharks and the dolphins try to avoid each other while living in the wild, large shark species are still considered the natural predators of these marine animals. Other than that, killer whales can sometimes prey on bottlenose dolphins, but these cases are sporadic. Even though the stingrays are not the natural predators of the dolphins, there is evidence where dolphin deaths took place due to the infection trauma and poisoning caused by a stingray wound.
Sometimes dolphins can die prematurely when these animals strand themselves on a beach. An individual dolphin gets stranded on the beach most of the time due to an injury or illness.
There have even been many mass stranding of the dolphins. Such incidents, even though rare, can take place for several reasons.
- The dolphins can get stranded after they try to follow their leaders as it moves out of the water onto the shore.
- Dolphins use the earth’s magnetic field for navigation can also strand themselves after magnetic field disturbances.
- The beaches structure can also prevent the dolphins’ sonar from detecting the presence of the shore before they get stranded.
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For the dolphins, fishing nets can be significantly life-threatening. The monofilament gill nets are very dangerous to dolphins because it’s hard for them to detect the presence of these nets using their echolocation technique. Since dolphins need to come up to the surface to breathe, they can suffocate if they get tangled up by these nets.
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Every year about 300,000 dolphins and other cetacean animals face death or injury due to fishing practices.