Introduction to River Dolphins
With only 4 species of dolphins being able to survive in freshwater, there is plenty of interest surrounding the River Dolphins. There are several known subspecies though that are found as well. The fact that they are very similar to other dolphins but they don’t need saltwater is interesting to explore.
River Dolphins Description
The size of a River Dolphin varies significantly depending on where they live. Some of them are up to 8 feet long but most of them are quite a bit smaller than that. They are one of the rare types of dolphins that feature a variety of colors. They can be yellow, pink, black, gray, brown, or white. Many people don’t realize it is a dolphin they have seen in the river due to the colors as they assume all dolphins are blue or gray.
River Dolphins Distribution
There are quite a few known rivers out there where these dolphins call home. They tend to stay in areas though that offer them coastal access and that are brackish. The following rivers have them- Mekong, Yangtze, Indus, Amazon, and Ganges. The locations are dense and often surrounded by the poor villagers.
These aren’t clean rivers though most of the time, often filled with water that is dark and very murky. The level of pollution is quite high so it is amazing that River Dolphins are able to do well in it. Other species of dolphins continually have huge issues due to pollution. This is just one more of the many mysteries surrounding these dolphins that needs further evaluation.
River Dolphins Behavior
They are very social dolphins, and they live in groups that are called pods. There can be a handful or more than 100 River Dolphins in a single pod. They form bonds that are deep and they seem very protective of the members. They keep the young and the juveniles at the center of the pod for additional safety. The females also work together to care for the young instead of only caring for their own. The hierarchy is very complex within the pods of the River Dolphins. Some of them seem to have mainly males or mainly females in them.
River Dolphins Feeding
Eating a variety of fish is the main source of food for these dolphins. They can consume very large amounts of food on a daily basis. They hunt for food as a collective effort with many pod members using echolocation and cooperation to successfully surround the fish and to be able to dive in for a meal.
River Dolphins Reproduction
Mating times significantly vary based on where the River Dolphins live. The females mate when they are around 8 years old and for the males it is about 10 years of age. The males are very competitive and do all they can to be the selected one to mate with a female. After mating occurs, it can be from 10 to 12 months when the young calf arrives.
The young will consume milk from the mother for a period of time that ranges from 1 ½ to 2 years. They will also start to eat fish when they are about 6 months old. While the mother is giving birth, other females will surround her to comfort her and offer protection. They also help the new arrival to reach the surface for air. The bonding that occurs here is amazing to observe.
River Dolphins Conservation Status and Threats
The current status of the River Dolphin is from vulnerable to critically endangered. The fact that it is so hard to get a good count of them makes it impossible to know how many of them are in the wild. They can be very spread out and the waters are very dark. While they can live in locations with pollution, it is still believed to be a factor for their deaths. Efforts to clean up the water aren’t really possible in these poor regions where even the people around the water in surrounding villages have very poor living conditions.
Fishing nets are also a problem for these dolphins as they can easily get tangled up in them. Even if they aren’t injured, they could end up drowning. Hunting these dolphins for meat that villagers eat happens on a regular basis. Too many fishing nets in the water is also a concern as it means these dolphins find it harder and harder to get enough food for their own survival.
As a result, the Baiji River Dolphin has been considered functionally extinct since late 2006. They were last seen in the wild in 2004. There were some reports of them in 2007 but nothing that could be substantiated and confirmed. Many believe that if efforts aren’t continued to help the River Dolphins then there is going to be more of the subspecies that see the same fate.