How many people know that dolphins and porpoises are different species? Carel Loubser looks into the differences between the two – and other fascinating dolphin facts.
Mammal or fish?
Both dolphins and porpoises are indeed mammals even though they both live in the ocean. They have lungs and not gills, and need to break the water to “catch a breath”. Both species also give birth to their young and nurse them after they are born.
So where do they differ?
Even though they belong both to the same scientific suborder, Odontocetti, they do not belong to the same scientific family. Porpoises belong to the Phocoenidae family and dolphins to the Delphinidae family. Toothed whales also belong to the suborder Odontocetti and all members can detect objects around them using sound echoes, through echolocation.
Dolphins tend to be larger than porpoises. Dolphins can reach 10 feet and longer while porpoises rarely reach seven feet. Porpoises are also more compact and often look chubby in comparison to the leaner and sleeker dolphins.
Snouts, fins and teeth…
A porpoise has a blunt, rounded nose while dolphins have a beak-like, pointed snout.
The dorsal fins of a porpoise are more triangular like sharks. On the other hand, a dolphin’s dorsal fin is more curved, like a wave.
It is very easy to tell the two apart by looking at their teeth. A porpoise’s teeth are flat and rectangular. Dolphin’s teeth are cone-shaped.
Dolphins live in much larger groups than porpoises and tend to show little fear of humans. They are more outgoing and often interact with humans, swimming alongside boats.
Porpoises live in small pods of two to four animals and are very shy. They will rarely approach a boat and hardly ever interact with humans.
Dolphins can live up to 50 years while the life expectancy of a porpoise is only 15 to 20 years. It is believed that reason is that porpoises reproduce faster than dolphins and this takes a toll on their bodies.
Porpoises make sounds that humans are not able to hear, but humans are able to hear the sounds of a dolphin.
What do dolphins eat?
Dolphins are carnivores and will eat squid, crustaceans and fish.
How do dolphins breathe?
Dolphins consciously need to remind themselves that they need to breathe, as they do not do this automatically. Dolphins can never really fall asleep or lose consciousness. But being mammals their brains need to rest. To manage this they will put half of their brain to sleep and will rotate periodically between the two spheres. Doing this allows them to be conscious enough to control their breathing and periodically swim to the surface for air, while still giving their brain the rest it needs.
Gangsters of the sea…
Dolphin pods of up to 120 members have been recorded before. These pods will form a number of different types of alliances, each playing a special role. Some groups will consort with the “enemy” to distract them enough to lure the females away from the enemy pod for mating. Other groups will recruit males from other pods to help them to steal more females and to protect their females. Lastly, a group can be charged with acting as liaisons to get allies in order to form dolphin “armies” if needed.
Is Flipper really that intelligent?
Dolphins are one of the most intelligent animals on the earth. They have large brains that allow complex cognition. They are capable of self-recognition, communication and cultural transmission.
By using a complex communication system dolphins are able to teach their young to use tools and it is even believed that a cultural characteristic of holding a funeral ceremony for their dead is possible.
One final interesting fact…
Male dolphins have a retractable penis that swivels. As a side effect of this dexterity, dolphins sometimes use their penis like humans use their hands, to feel out or explore objects.
Written by Carel Loubser, Wilderness Safaris Blog Contributor
Photos by Dana Allen & Anthony Grote