The dusky dolphin can be seen swimming primarily in the coastal waters of the southern hemisphere in locations such as Africa, New Zealand, South America and a few other islands, although they may also be found at times swimming in offshore waters as well.
These dolphins prefer cool to cold waters and while they can be known for traveling great distances they do not show any distinct migration patterns.
They are well-known for their highly acrobatic behaviors, performing a combination of leaps, flips, rolls and turns and can learn how to perform these tricks by watching more experienced dolphins at play.
The largest of the dusky dolphins can grow to a length of up to 6 ft. long and weigh over 200 pounds.
In terms of color these dolphins have a dark grey to black back and a white stomach and throat area.
The front of the dorsal fin is a dark grey color but lightens towards the back.
They have a long narrow skull with a dark-colored beak and lower jaw.
The dusky dolphin belongs to the toothed whale family because it possess teeth which is uses to grab onto its prey and prevent it from escaping.
Some of their most common foods include red cod, lantern fish, anchovies, horse mackerel and hoki.
When hunting for food they can often be observed using strategic group oriented hunting techniques to isolate and capture their prey.
These dolphins typically hunt in large groups and hunting can take place either in the day or at night depending on the group doing the hunting and their location.
The size of the pod, the food they are searching for and the depth of the water can also play a large role in determining their hunting methods.
Some of these hunting methods include chasing or circling their prey, forcing them to the surface of the water and herding them into a small tight ball where they can then be cornered by the coastline or the hull of a ship.
One group of dolphins may enclose a group of fish and herd them into a tight ball while another group of dolphins force the fish to the surface.
Once they have the fish where they want them they will then take turns going through the herd and picking off the defenseless fish.
Although most hunting takes place near the surface these dolphins may also hunt their prey at deeper depths.
The deeper they hunt however the smaller their hunting groups tend to be as most groups gather closer to the surface of the water.
During these times the dolphins will dive into deep waters in grouped layers to isolate and pick off individual prey.
In addition to hunting in groups the dusky dolphin also possesses echolocation which allows them to search for food, navigate the ocean and detect potential predators in complete darkness.
By sending out echo’s and listening to the sound that returns to them these marine mammals can determine the direction, angle, speed, density and characteristics of the objects around them.
Echolocation is essential because it uses sound (not eyesight) to identify objects in the dolphins surrounding area and provides the dolphin with the ability to observe things it cannot see with its own eyes.
At night and in dark areas echolocation becomes a vital tool for their survival.
Dusky dolphins often live in large pods which can easily exceed 100 dolphins and in some cases may number into the thousands.
The largest groups often occur when hunting for food and are generally smaller when traveling, resting or performing other social activities.
Although they may travel great distances these dolphins do not follow any particular migration patterns or routes.
They are highly active and can be seen playing together and performing various areal acrobatics.
It is believed that these dolphins are not born with this talent, but learn these skills by observing more experienced dolphins perform.
Dusky dolphins are believed to begin mating between the ages of 6 – 8.
The average gestation period (the period from conception to birth) lasts from 12 – 13 months for female dolphins and pregnancy occurs once every 2 1/2 – 3 years.
After birth mothers may nurse their children for up to 12 months by feeding them milk from their mammary glands.
During this nursing period mothers and their young often gather in shallow waters where they can rest and take care of their babies and provide them with better protection from threats.
Dusky dolphins are not a monogamous species and male groups of up to 10 can be seen taking turns mating with a single female during reproductive periods.
In addition to breeding dusky dolphins may also mate for social purposes, not just to reproduce but to bond and for pleasure.
Unfortunately not much is known about the overall abundance of this species so there are no official estimates in terms of population size.
Their food supply is also sometimes threatened by sharks who attempt to steal the food they’ve hunted after their food has been scared and gathered into a tight ball near the surface of the water.
Human threats include being accidentally caught and killed in fishing nets and possible collisions with boats, although this is much less common.
To minimize human interference that could harm the dusky dolphin these dolphins are considered a protected species making commercial hunting activities illegal; and anyone caught illegally hunting these marine mammals may be faced with steep fines and other legal action.