Yangtze finless porpoise facts for kids
Quick facts for kids Yangtze finless porpoise |
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| At the Chinese Academy of Sciences | |
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| Genus: |
Neophocaena
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| Species: |
asiaeorientalis
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| Yangtze finless porpoise distribution | |
The Yangtze finless porpoise (Neophocaena asiaeorientalis) is a special type of toothed whale. It belongs to the porpoise family. This amazing animal lives only in the Yangtze River in China. It is China's only freshwater cetacean (a group that includes whales, dolphins, and porpoises). Another freshwater dolphin, the baiji, used to live there too, but it might be extinct now.
The Yangtze finless porpoise is an endangered animal. Experts believe only about 1,000 of them are left. These small whales face many dangers. Things like illegal fishing, pollution, lots of boat traffic, and dam building hurt them. Because their numbers are dropping fast, the Chinese government and conservation groups are working hard to save them.
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What is a Yangtze Finless Porpoise?
The Yangtze finless porpoise is a freshwater cetacean. This means it is a whale, dolphin, or porpoise that lives in fresh water. Finless porpoises first lived in the salty waters of the Indo-Pacific Ocean. But some of them moved into the freshwater Yangtze River.
Scientists have studied these porpoises. They found that the East Asian finless porpoise and the Yangtze finless porpoise have been separate for thousands of years. They used to be thought of as the same species. But now, genetic studies show that the Yangtze finless porpoise is its own unique species.
What are its Names?
In Mandarin Chinese, people call it jiangtun. This name means "river piglet."
How Do They Look?
A finless porpoise can grow up to about 7.4 feet (2.27 meters) long. It can weigh up to 158 pounds (71.8 kilograms). Most are a bit smaller than this. An average adult is usually 5 to 6 feet (1.5 to 1.8 meters) long. They weigh around 100 pounds (45 kilograms). Female porpoises are usually smaller than males.
Their flippers are curved with pointed ends. They are quite large, about 20% of their total body length. The porpoise's body is thick in the middle. It gets thinner towards the tail. They are generally more slender than most other porpoises. These cetaceans also have unique foreheads. Their forehead is very steep, and they do not have a beak. They also have a neck that can move freely. This is because their neck bones are not fused together. They have 15 to 22 pairs of teeth on their upper and lower jaws.
What is a Dorsal Ridge?
As their name suggests, these porpoises have flat backs. They do not have a dorsal fin. Instead, they have a dorsal ridge or "groove." This ridge is covered in small, round bumps called tubercles.
Recent studies show that these tubercles help the porpoise. They act as a sensory organ. They can also help the porpoise move through the water. The number of tubercle rows and the size of the dorsal ridge can be different. It depends on the porpoise's species and where it lives. The Yangtze finless porpoise usually has a higher, narrower ridge. It has only 1 to 10 rows of tubercles.
What Color Are They?
Their body color changes depending on where they live and how old they are. Newborn Yangtze finless porpoises are usually dark gray or black. This color gets lighter to a pale gray within a few months. After a Yangtze finless porpoise dies, its body usually turns black.
Where Do They Live?
The Yangtze finless porpoise lives in the main part of the Yangtze River. They also live in the lakes connected to it. They only live in fresh water. This makes them different from other finless porpoises.
They often live in shallow bay areas, swamps, and estuaries all year. They do not migrate. But where they are found can change with the seasons. In winter, most are found in the middle and lower parts of the Yangtze River. They prefer warm, tropical temperatures.
What Do They Eat?
The diet of the Yangtze finless porpoise can change. It depends on the season and what prey is most common. This suggests they are opportunistic feeders. This means they eat whatever food is easiest to find. Some common fish they eat include Coilia brachygnathus and Pseudobrama simoni.
How Do They Behave?
The Yangtze finless porpoise is usually shy. It does not often come to the water's surface when people are nearby. They are usually most active when they are eating. They spend most of their time near river banks. They also like to be where two waterways meet.
Yangtze finless porpoises travel in small groups. These groups usually have about three to six porpoises. But groups of 20 have been seen. Studies show they often make one long dive. Then they follow it with two shorter dives. Longer dives are more common during the day. In the Yangtze River, these porpoises are known to leap from the water. They also perform "tail stands." At night, they tend to sleep and are less active.
Mothers have sometimes been seen carrying their babies on their backs. This is a unique behavior. Another special thing about these porpoises is how they communicate. Most dolphins use whistles. But these porpoises use echolocation and ultrasonic pulses. This means they send out sounds and listen for the echoes. This helps them find food and navigate.
What is Their Status?
The Yangtze river dolphin is now functionally extinct. The Yangtze finless porpoise population is also dropping very fast. Because of this, the Chinese government has given it the highest protection status. It is called a National First Grade Key Protected Wild Animal. This means it is illegal to harm a porpoise.
However, their numbers are still falling faster. This is due to less food, pollution, and ship movement. There is a high chance (86.06%) they could become extinct in the next 100 years. Underwater noise pollution is another reason their numbers are dropping. If the noise in the water is too loud, it threatens their survival. Global conservation groups like the World Wildlife Fund and IUCN are working with the Chinese government to save them.
What Are the Threats?
Fishing Dangers
Sometimes, porpoises get caught by accident in fishing nets. This is called Bycatch. It is a reason for their decline. Illegal fishing and dangerous nets, like gillnets, are common in the Yangtze River. The areas where porpoises live often overlap with where gillnets are used. This makes porpoises very likely to get tangled and drown.
River Development
More boat traffic, pollution, and damage to the river's habitat have caused their numbers to drop. More boats mean porpoises can be hit by propellers. Boat noise can also make it hard for porpoises to talk to each other. It also messes with their biosonar. This makes it harder for them to find food and move around. Deaths from boat collisions have increased a lot recently.
Widespread sand mining in the river and lake beds destroys important homes for porpoises. It also removes their food sources. This problem is very serious in the Dongting and Poyang Lakes.
Many people live along the river. Thousands of factories are also there. They release huge amounts of sewage and waste into the river. In April 2004, five porpoises died in Dongting Lake. This happened in just one week. It was likely due to pesticides. It might have also been from long-term exposure to mercury and chromium.
Dams also greatly affect the river and lake environment. They block porpoises from moving between the river and its lakes or smaller rivers. They also affect fish that porpoises eat. The Three Gorges Dam has changed the conditions downstream in the Yangtze River. Building the Poyang Lake Dam could severely harm the remaining porpoise population.
How Are They Being Saved?
In 2014, only 505 porpoises were left in the main part of the Yangtze River. Their numbers were dropping very fast. From 2006 to 2012, the porpoise population decreased by more than half. A 2012 survey showed the decline rate was 13.7% per year. But by 2017, the number in the Yangtze had increased to 1,012! Thanks to protection efforts, porpoises have been seen again in places like Nantong. They were rare there before.
The big growth of Chinese industry since 1990 has caused many problems. It led to more shipping and pollution. This damaged the environment. To protect the species, China's Ministry of Agriculture made it illegal to harm a porpoise.
The Tian-e-Zhou Oxbow Nature Reserve has worked for years to protect the porpoises. This reserve is supported by the Chinese government, World Wildlife Fund, and others. They increased their porpoise population from five to forty in 25 years. By 2017, there were 80 porpoises there. The Chinese Academy of Science's Wuhan Institute of Hydrobiology is also working to help. They have placed five porpoises in another safe area called the He-wang-miao oxbow.
Five protected natural reserves have been set up. These are in areas where many porpoises live or die. In these areas, harmful fishing gear is banned. Scientists are also studying porpoise biology. This helps them with captive breeding. The Baiji Dolphinarium was set up in 1992. It allows scientists to study how porpoises behave and reproduce.
The first Yangtze finless porpoise born in captivity was on July 5, 2005. This happened at the Baiji Dolphinarium in Wuhan.
