Yes, dolphins can drown when they are submerged underwater if they inhale water while they are submerged or run out of oxygen because they are very different from fish and amphibians that are able to extract oxygen directly from the water.
The reasons for this is that dolphins are marine mammals and they share many of the same characteristics with other mammals such as breathing air, being warm-blooded and giving birth which makes them a distinct species from fish and amphibians that use gills to extract oxygen from the water, are mostly cold-blooded and produce eggs that hatch into offspring.
As stated earlier in order for a dolphin to breathe it must come to the surface of the water and inhale oxygen through its blowhole.
Sometimes when a dolphin surfaces and exhales water can be seen spouting from its blowhole high into the air.
When a dolphin spouts water it is actually forcing the surrounding water away from its blowhole.
Many people believe that dolphins inhale water and then spit it out of their blowhole when they surface but this isn’t the case because if a dolphin inhales water while its submerged it would enter the dolphins lungs and cause the dolphin to suffocate and drown similar to the way a human would drown if they tried to inhale while underwater.
Another interesting fact about dolphins is the fact that their air passage and food passage are not connected.
In other words dolphins breathe exclusively from their blowhole and eat exclusively from their mouth.
Unlike humans dolphins are unable to breathe from their mouth which is very important because as dolphins dive underwater to hunt for food they need to be able to consume their prey while they are submerged without the fear of accidentally inhaling water and getting it in their lungs.
In terms of how long a dolphin can dive for some dolphins are able to hold their breath for up to 20 minutes before coming up for air while other dolphins are only able to hold their breath for 5 – 7 minutes.
The length of time that a dolphin can hold its breath for varies from one species to the next.
Part of this may be due to their hunting methods (some species hunt at deeper levels and require longer dives to capture food) or their physiological abilities (some species are simply better equipped to handle longer dives).
In additional to the dolphin species whales and porpoises are also marine mammals and share many of the same physiological traits of their dolphin relatives such as breathing above the surface of the water through their blowhole.
Common traits among mammals
- Breathe air (oxygen must be obtained above the surface of the water)
- Warm-blooded (mammals tend to have fat/blubber in order to maintain their body heat and must consume adequate calories to stay warm and healthy)
- Have hair (in addition to fat/blubber some mammals have hair to help them stay warm in cold climates)
- Give birth (most mammals go through a pregnancy period and give birth to their babies; few species lay eggs)
- Produce milk (most female mammals produce milk after their child is born in order to provide the child with nutrients, fat and calories so that it can remain healthy and grow)