The northern right whale dolphin is a mid-sized dolphin that can be found living in the north pacific ocean, particularly around the Continental shelf and slope.
These dolphins are known for their dark gray to black skin tone and complete lack of a dorsal fin; just like their southern right whale relatives.
Although they can be seen aggregated into large pods they tend to be shy and cautious when around boats or people.
The northern right whale dolphin belongs makes up one of over 40 species of dolphin.
Physical Characteristics and Appearance
At full size the female northern right whale dolphin averages between 6 1/2 – 8 1/2 ft. long with males known to grow up to 10 ft. long.
These marine mammals have a streamlined body that’s widest in the center and tapers down at the head and flukes.
When compared to other dolphin species the northern right whale dolphin appears to have a slimmer than normal profile.
The head curves down towards the beak which is short and pointed in nature.
Swimming involves the use of a pair of small, narrow flippers that are pointed at the end.
Unlike other dolphin species these marine mammals do not posses a dorsal fin, ridge or hump, however the overall profile of the back is curved.
In terms of color these dolphin are primarily black or dark gray with a light gray or white under body and patch on the chin.
When compared to the southern right whale dolphin these dolphins have more of a black uniformed color overall.
At birth however these dolphins have a creamy or grayish brown skin tone that turns dark after about a year.
As marine mammals the northern right whale dolphins are warm-blooded, breathe air, give birth and produce milk..
Diet and Hunting Methods
They may also consume hake, mesopolagic fish and saury.
Given the social nature of these marine mammals it is quite possible that echolocation may be used during group hunting in order to strategies and plan their hunting efforts and keep track of other members of group.
To assist with capturing their prey the northern right whale dolphin has 74 – 108 individual small, sharp teeth, however it is unknown whether their teeth are used tear their prey apart or simply grab onto it in order to swallow their prey whole.
During short bursts these marine mammals can reach speeds of up to 22 mph, which may be used for capturing prey and/or escaping threats.
Habitat and Migration
As the name suggest the northern right whale dolphin can be found swimming in the north pacific ocean.
These dolphins tend to prefer deep cool waters in and around the Continental shelf and slope between 17 – 22 degrees Celsius.
They can be seen in areas such as the Gulf of Alaska, northern Baja California and Japan among other locations.
During certain times of the year these marine mammals may migrate when water temperatures begin to change.
During the colder months (fall/autumn and winter) the northern right whale dolphin may head down south as the waters begin to cool in order to maintain a suitable temperate and migrate back north when the waters begin to warm up again (spring and summer).
Social Structure and Communication
The northern right whale dolphin can be spotted swimming in groups containing several dozen dolphins, however they may also be commonly found in pods of up to 200 dolphins.
During certain social events groups may expand considerably to contain as many as 3,000 northern right whale dolphins.
Pods aren’t just limited to the northern right whale dolphin either as these dolphins can frequently be seen intermingling with a number of different cetaceans.
When interacting with one another these dolphins have been known to breach, lob tail, belly flapping and bow-riding waves, however they have also been spotted moving slowly and inconspicuously through the water.
Observations tend to show these dolphins as cautious and shy when it comes to approaching boats or people.
Vocal communication is created by using a series of high-pitched clicks and whistles that allow these dolphins to communicate with their pod important findings or interests that they may want to share with other dolphins and pod members.
Reproduction and Breeding
Very little is known about the gestation period or lifespan of these dolphins.
It is believed that the northern right whale dolphin reaches sexual maturity between the ages of 9 – 11 and the majority of mating/reproduction tends to occur between winter and early spring.
With that said there have been observations of mating occurring during the summer months which suggests that the northern right whale dolphin may mate and reproduce all year long.
There is also data that suggests that the average gestation period is likely to be between 11 – 13 months with reproductive cycles lasting at least 2 years apart.
In other words it is likely that these marine mammals give birth once every 2 years or longer and the likelihood of having an additional child before the 2 year cycle is uncommon.
As stated earlier the northern right whale dolphin is a marine mammal and because they are marine mammals they give birth to their young (they do not lay eggs) and nurture their young by feeding them with milk shortly after birth.
When it comes to predators there is no conclusive information regarding animals that may prey on them, however given their habitat it is quite possible that the northern right whale dolphin may be hunted by killer whales and large sharks.
Aside from natural predators these marine mammals have also been caught in fishing nets and other fishing equipment which can lead to injury and/or drowning.
On the other hand there hasn’t been much information reported on poaching/hunting activities related to these marine mammals, however this cannot be counted out and may occur from time to time depending on their geographic location.
Lastly, the northern right whale dolphin may face threats from pollution and/or habitat degradation, but are much less likely to be susceptible to these conditions given their offshore nature and habitat.