The harbour porpoise is a small sea animal. 
The harbour porpoise is a small sea animal. 
These animals have dark grey backs. Their bellies are white. 
They eat many small fish. This helps them grow. They can eat hundreds of fish in one night.
They make short clicking sounds. They use these sounds to find things. This helps them see in the water.
Some porpoises live in the sea. Others swim up rivers. They are amazing animals to watch.
The harbour porpoise is a small sea animal. 
These animals have dark grey backs. Their sides are a lighter grey. Their bellies are white. 
Porpoises use clicks to find food. This is called echolocation. They send out short sounds. The sounds bounce off things. This helps them see in the dark water. They eat many small fish. They might eat 550 fish in one night! 
Most porpoises like to be alone. They usually swim in groups of five or less. They can live for about 8 to 13 years in the wild.
Fishing nets can be a danger. Porpoises can get stuck in them. This is called bycatch. People use loud tools called pingers to help. These tools keep porpoises away from nets.
The harbour porpoise is a small sea animal that lives in cool waters. 

These animals have a very specific way of finding food. They use a tool called echolocation. They make short clicking sounds that last only a few milliseconds. These clicks bounce off things in the water. This helps the porpoise know where fish are hiding. They eat many small fish like herring, cod, and sardines. A porpoise near Denmark might eat 200 fish during the day. At night, they might eat as many as 550 fish! 
People have studied these animals for a very long time. The name "porpoise" comes from old French words. Those words actually come from Latin words for "pig" and "fish." This is because they were thought to look like sea pigs. The scientific name is Phocoena phocoena. This name comes from a Greek word that means "big seal." Aristotle once described them this way a long time ago. 
Harbour porpoises have many interesting physical facts. A baby is about 60 centimetres long at birth. Most adults weigh between 50 and 70 kilograms. Females are often heavier than the males. Their backs and fins are a dark grey colour. Their sides are a lighter, speckled grey. Their bellies are usually white with grey stripes. 
In the wild, these animals usually live for 8 to 13 years. Most porpoises like to be alone or in small groups. They rarely swim in groups larger than five animals. They must be careful of predators like killer whales and sharks. They also face a hard job with fishing nets. Sometimes they get caught in nets by accident. This is called bycatch. People use loud tools called pingers to keep them safe.
The harbour porpoise, known scientifically as Phocoena phocoena, is a small cetacean that lives in cool coastal waters. 

Physically, the harbour porpoise is quite robust. At birth, they are about 60 centimetres long. Most adults weigh between 50 and 70 kilograms. Interestingly, females are often heavier than males. Their bodies are dark grey on the back, fins, and tail. The sides are a lighter, speckled grey. Their undersides are mostly white with grey stripes along the throat. Some individuals even appear anomalously white in places like the North Atlantic or the Bay of Fundy. 
To navigate and hunt, these animals use a mechanism called echolocation. They produce vocalizations consisting of short clicks. Each click lasts between 0.5 and 5 milliseconds. These clicks occur in bursts that can last up to two seconds. The frequency of these sounds is between 1000 and 2200 hertz. By listening to how these sounds bounce off objects, the porpoise can locate prey. This is essential for their survival in murky coastal waters.
Harbour porpoises are categorized into several distinct populations or subspecies. In the North Atlantic and West Africa, they are classified as P. p. phocoena. The populations in the Black Sea and Sea of Azov are P. p. relicta. There is also an unnamed population in the northwestern Pacific. In the northeastern Pacific, they are known as P. p. vomerina. Recent studies suggest the North Atlantic population is even more complex, with at least three genetically distinct subspecies. 
The history of the porpoise name is quite fascinating. The English word comes from Old French and Medieval Latin. The Latin roots combine "porcus" (pig) and "fish." This suggests they were once seen as "sea swine." Their scientific name, Phocoena phocoena, comes from the Greek word "phōkaina," meaning "big seal." This description was famously made by the philosopher Aristotle. In Norway, they are called "nise," a word related to sneezing. This refers to the sound they make when surfacing to breathe.
These animals have a very active feeding lifestyle. They primarily eat small schooling fish like herring, cod, and sardines. They may also eat squid or crustaceans. A study near Denmark showed they are very efficient hunters. They can catch 200 fish per hour during the day. At night, that number can rise to 550 fish per hour. They catch about 90% of the fish they target. To maintain their energy, young porpoises must eat about 7% to 8% of their body weight every day.
Despite their abundance, harbour porpoises face many natural and human threats. They are preyed upon by white sharks, killer whales, and grey seals. In some areas, bottlenose dolphins even attack them. The most significant human threat is bycatch. This happens when porpoises get caught in static fishing gear, like gill nets. These nets are anchored to the sea floor and can be 400 metres long. To help, researchers use "pingers," which are acoustic devices that scare porpoises away from the nets.
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