Finless Porpoise

The finless porpoise is a small marine mammal that can be found swimming in the coastal waters of Asia primarily in the Yangtze, Western Pacific and Indian Oceans.

This porpoise makes up one of six species of porpoise and belongs to the group known as Cetacea, which includes all species of whaledolphin and porpoise and is divided into two suborders known as the toothed whale and baleen whale suborders based on the animals characteristics.

All species of porpoise fit into the toothed whale suborder due to their presence of teeth.

As the name suggest the finless porpoise is almost completely finless.

Instead of a large fin it has a small hump or ridge with small bumps known as  tubercles that are visible on the middle of its back.

Physical Characteristics

The finless porpoise is mostly a grayish color although it appears black at the time of birth.

After several months the dark coloring of the porpoise begins to fade and after six months it is almost completely gray.

Adult porpoises can reach an average hight of around 5 – 6 ft in length and weigh as much as 100 pounds.

They have an un-fused neck which helps them view their surroundings easily and a small curved mouth.

Diet

The diet of the finless porpoise can vary from one location to the next however they are primarily known for eating fish, prawn, squid, octopus and shrimp.

Migration

Limited information suggest that finless porpoises are not a migratory species and can be found living in coastal waters year round.

Social Structure

Most finless porpoises can be seen traveling alone or in small pods of up to 12.

The majority of pods traveling together often consists of 2 porpoises (a mother and her child).

In rare cases several dozen pods may be seen aggregating together (usually during times of feeding) and may form groups of up to 50.

Breeding

Breeding typically occurs during the spring/summer months of the year.

The gestation period (the period from conception to birth) lasts about 10 – 11 months.

After birth the child can be seen clinging onto the mothers back as she swims.

Females feed there young by producing milk from their mammary glands.

Depending on the mother and child feeding can continue anywhere from 6 months to over a year.

It is believed that sexual maturity is reached between 4 – 6 years of age and that the average lifespan ranges from 20 – 30 years.

As stated before the mother is generally the care giver and will swim with her child until the child is fully matured.

Threats

Unlike other species of Cetacea the finless porpoise has never really been hunted by humans.

While there are a few cases of them being hunted in the early 1900’s for the most part they have remained a protected and rarely hunted species.

Since these porpoises are primarily coastal their main threats include being entangled in fishing nets, collisions with boats, noise and water pollution and the construction of damns, harbors and other man-made structures.

Due to their coastal environment, the increased threats they face and their shrinking population, the finless porpoise is currently considered vulnerable or endangered depending on where they are found.